Danfoss FC 100 Series Soft Start Controller Installation Guide

June 1, 2024
Danfoss

Danfoss FC 100 Series Soft Start Controller

Danfoss-FC-100-Series-Soft-Start-Controller-image

Specifications

  • Software Version: 2.5x
  • Compatibility: All VLT HVAC adjustable frequency drives with software version 2.5x

Product Information

The VLT HVAC Drive FC 100 Series is designed for use with HVAC systems and offers advanced control features for efficient operation.

Safety Features

  • CE labeling for compliance with safety standards
  • Designed to operate in various air humidity conditions
  • Resistant to aggressive environments
  • Shock and vibration resistant

Control and Operation

  • PID control for precise operation
  • EMC compliant for electromagnetic compatibility
  • Galvanic isolation (PELV) for enhanced safety
  • Control with brake function for specific applications

VLT HVAC Selection

  • Efficiency optimization for energy savings
  • Low acoustic noise for quiet operation
  • Peak voltage on motor regulation
  • Special conditions support
  • Options and accessories availability for customization

Product Usage Instructions

Installation

  • Mechanical Installation: Follow the guidelines provided in the manual to securely mount the VLT HVAC Drive.
  • Electrical Installation: Connect the drive to the power supply following the specified wiring diagram.

Application Examples

Utilize different control modes such as Start/Stop, Potentiometer Reference, Automatic Motor Adaptation (AMA), and more based on your HVAC system requirements.

RS-485 Installation and Set-up

Set up the RS-485 communication protocol using the provided guidelines for network configuration and message framing.

Troubleshooting

Refer to the manual for a list of alarms, warnings, and fault messages to troubleshoot any issues that may arise during operation.

FAQs

  • Q: How can I determine the software version of my VLT HVAC Drive?
    • A: You can find the software version number in parameter 15-43 of the drive.
  • Q: What safety features does the VLT HVAC Drive offer?
    • A: The drive includes CE labeling, resistance to air humidity, shock, vibration, and control with brake function for enhanced safety.
  • Q: How do I optimize energy efficiency with the VLT HVAC Drive?
    • A: You can optimize energy efficiency by utilizing the efficiency settings and options available in the drive. Refer to the manual for detailed instructions.

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VLT® HVAC Drive Design Guide
Contents
1 How to Read this Design Guide
Copyright, Limitation of Liability and Revision Rights Approvals Symbols Abbreviations Definitions
2 Introduction to the VLT HVAC Drive
Safety CE labeling Air humidity Aggressive Environments Vibration and shock VLT HVAC Controls PID General aspects of EMC Galvanic isolation (PELV) Ground leakage current Control with brake function Mechanical brake control Extreme running conditions Safe Stop
3 VLT HVAC Selection
Specifications Efficiency Acoustic noise Peak voltage on motor Special Conditions Options and Accessories
4 How to Order
Ordering form Ordering Numbers
5 How to Install
Mechanical Installation Electrical Installation
MG.11.B5.22 – VLT® is a registered Danfoss trademark.

Contents
1-1 1-2 1-3 1-3 1-4 1-4
2-1 2-1 2-2 2-4 2-4 2-5 2-18 2-20 2-31 2-33 2-34 2-35 2-37 2-38 2-39
3-1 3-1 3-12 3-13 3-14 3-14 3-19
4-1 4-1 4-3
5-1 5-1 5-6

Contents
Final Set-Up and Test Additional Connections Installation of misc. connections Safety EMC-correct Installation AC Line Supply Interference/Harmonics Residual Current Device
6 Application Examples
Start/Stop Pulse Start/Stop Potentiometer Reference Automatic Motor Adaptation (AMA) Smart Logic Control Smart Logic Control Programming SLC Application Example BASIC Cascade Controller Pump Staging with Lead Pump Alternation System Status and Operation Fixed Variable Speed Pump Wiring Diagram Lead Pump Alternation Wiring Diagram Cascade Controller Wiring Diagram Start/Stop conditions Compressor Cascade Control
7 RS-485 Installation and Set-up
RS-485 Installation and Set-up FC Protocol Overview Network Configuration FC Protocol Message Framing Structure Examples Modbus RTU Overview Modbus RTU Message Framing Structure How to Access Parameters Examples Danfoss FC Control Profile
8 Troubleshooting
Alarms and warnings

VLT® HVAC Drive Design Guide
5-19 5-22 5-26 5-29 5-29 5-33 5-34
6-1 6-1 6-1 6-2 6-2 6-2 6-3 6-3 6-5 6-6 6-6 6-7 6-8 6-8 6-9 6-10
7-1 7-1 7-3 7-4 7-5 7-11 7-12 7-13 7-17 7-19 7-25
8-1 8-1

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VLT® HVAC Drive Design Guide
Alarm words Warning words Extended status words Fault messages
9 Index

Contents
8-4 8-5 8-6 8-7
9-1

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Contents

VLT® HVAC Drive Design Guide

MG.11.B5.22 – VLT® is a registered Danfoss trademark.

VLT® HVAC Drive Design Guide

How to Read this Design Guide

1 How to Read this Design Guide
1
VLT HVAC Drive FC 100 Series Design Guide
Software version: 2.5x

This design guide can be used for all VLT HVAC adjustable frequency drives with software version 2.5x.
The software version number can be seen from parameter 15-43.

MG.11.B5.22 – VLT® is a registered Danfoss trademark.

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How to Read this Design Guide

VLT® HVAC Drive Design Guide

1.1.1 Copyright, Limitation of Liability and Revision Rights

1

This publication contains information proprietary to Danfoss A/S. By accepting and using this manual, the user agrees that the information contained

herein will be used solely for operating equipment from Danfoss A/S or equipment from other vendors, provided that such equipment is intended for

communication with Danfoss equipment over a serial communication link. This publication is protected under the copyright laws of Denmark and most

other countries.

Danfoss A/S does not guarantee that a software program produced according to the guidelines provided in this manual will function properly in every physical, hardware or software environment.

Although Danfoss A/S has tested and reviewed the documentation within this manual, Danfoss A/S makes no warranty or representation, neither expressed nor implied, with respect to this documentation, including its quality, performance, or fitness for a particular purpose.

In no event shall Danfoss A/S be liable for direct, indirect, special, incidental or consequential damages arising from the use or the inability to use information contained in this manual, even if advised of the possibility of such damages. In particular, Danfoss A/S is not responsible for any costs, including, but not limited to, those incurred as a result of lost profits or revenue, loss of or damages to equipment, loss of computer programs, loss of data, the costs to substitute these, or any claims by third parties.

Danfoss A/S reserves the right to revise this publication at any time and to make changes to its contents without prior notice or any obligation to notify former or present users of such revisions or changes.

1.1.2 Available Literature
– Instruction Manual MG.11.Ax.yy provides the neccessary information for getting the drive up and running. – Design Guide MG.11.Bx.yy provides all the technical information about the drive and customer design and applications. – Programming Guide MG.11.Cx.yy provides information on how to program and includes complete parameter descriptions. – Mounting Instruction, Analog I/O Option MCB109, MI.38.Bx.yy – VLT® 6000 HVAC Application Booklet, MN.60.Ix.yy – Instruction Manual VLT®HVAC Drive BACnet, MG.11.Dx.yy – Instruction Manual VLT®HVAC Drive Profibus, MG.33.Cx.yy. – Instruction Manual VLT®HVAC Drive Device Net, MG.33.Dx.yy – Instruction Manual VLT® HVAC Drive LonWorks, MG.11.Ex.yy – Instruction Manual VLT® HVAC Drive High Power, MG.11.Fx.yy – Instruction Manual VLT® HVAC Drive Metasys, MG.11.Gx.yy x = Revision number yy = Language code Danfoss Drives technical literature is also available online at www.danfoss.com/BusinessAreas/DrivesSolutions/Documentations/Technical+Documentation.htm

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VLT® HVAC Drive Design Guide 1.1.3 Approvals
1.1.4 Symbols
Symbols used in this guide. NOTE! Indicates something to be noted by the reader. Indicates a general warning.
Indicates a high-voltage warning.

  • Indicates default setting

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1.1.5 Abbreviations

1

Alternating current

American wire gauge

Ampere/AMP

Automatic Motor Adaptation

Current limit

Degrees Celsius

Direct current

Drive Dependent

Electro Magnetic Compatibility

Electronic Thermal Relay

drive

Gram

Hertz

Kilohertz

Local Control Panel

Meter

Millihenry Inductance

Milliampere

Millisecond

Minute

Motion Control Tool

Nanofarad

Newton Meters

Nominal motor current

Nominal motor frequency

Nominal motor power

Nominal motor voltage

Parameter

Protective Extra Low Voltage

Printed Circuit Board

Rated Inverter Output Current

Revolutions Per Minute

Second

Torque limit

Volt

VLT® HVAC Drive Design Guide
AC AWG A AMA ILIM °C DC D-TYPE EMC ETR FC g Hz kHz LCP m mH mA ms min MCT nF Nm IM,N fM,N PM,N UM,N par. PELV PCB IINV RPM s TLIM V

1.1.6 Definitions
Drive:
IVLT,MAX The maximum output current.
IVLT,N The rated output current supplied by the adjustable frequency drive.
UVLT, MAX The maximum output voltage.
Input:

Control command You can start and stop the connected motor using the LCP and the digital inputs. Functions are divided into two groups. Functions in group 1 have higher priority than functions in group 2.

Group 1 Group 2

Reset, Coasting stop, Reset and Coasting stop, Quick stop, DC braking, Stop and the “Off” key. Start, Pulse start, Reversing, Start reversing, Jog and Freeze output

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VLT® HVAC Drive Design Guide
Motor:
fJOG The motor frequency when the jog function is activated (via digital terminals).
fM The motor frequency.
fMAX The maximum motor frequency.
fMIN The minimum motor frequency.
fM,N The rated motor frequency (nameplate data).
IM The motor current.
IM,N The rated motor current (nameplate data).
nM,N The rated motor speed (nameplate data).
PM,N The rated motor power (nameplate data).
TM,N The rated torque (motor).
UM The instantaneous motor voltage.
UM,N The rated motor voltage (nameplate data).

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Break-away torque
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VLT® HVAC Drive Design Guide

VLT The efficiency of the adjustable frequency drive is defined as the ratio between the power output and the power input.
Start-disable command A stop command belonging to the group 1 control commands – see this group.
Stop command See Control commands.
References:
Analog Reference A signal transmitted to the analog inputs 53 or 54 can be voltage or current.
Bus Reference A signal transmitted to the serial communication port (FC port).
Preset Reference A defined preset reference to be set from -100% to +100% of the reference range. Selection of eight preset references via the digital terminals.
Pulse Reference A pulse frequency signal transmitted to the digital inputs (terminal 29 or 33).
RefMAX Determines the relationship between the reference input at 100% full scale value (typically 10 V, 20 mA) and the resulting reference. The maximum reference value set in par. 3-03.
RefMIN Determines the relationship between the reference input at 0% value (typically 0 V, 0 mA, 4 mA) and the resulting reference. The minimum reference value set in par. 3-02.

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Miscellaneous:

Analog Inputs

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The analog inputs are used for controlling various functions of the adjustable frequency drive.

There are two types of analog inputs:

Current input, 0-20 mA and 4-20 mA

Voltage input, 0-10 V DC.

Analog Outputs The analog outputs can supply a signal of 0-20 mA, 4-20 mA, or a digital signal.

Automatic Motor Adaptation, AMA AMA algorithm determines the electrical parameters for the connected motor at standstill.

Brake Resistor The brake resistor is a module capable of absorbing the braking energy generated in regenerative braking. This regenerative braking energy increases the intermediate circuit voltage, while a brake chopper ensures that the energy is transmitted to the brake resistor.

CT Characteristics Constant torque characteristics used for screw and scroll refrigeration compressors.

Digital Inputs The digital inputs can be used for controlling various functions of the adjustable frequency drive.

Digital Outputs The drive features two solid state outputs that can supply a 24 V DC (max. 40 mA) signal.

DSP Digital Signal Processor.

Relay Outputs: The adjustable frequency drive features two programmable relay outputs.

ETR Electronic Thermal Relay is a thermal load calculation based on present load and time. Its purpose is to estimate the motor temperature.

GLCP: Graphical Local Control Panel (LCP102)

Initializing If initializing is carried out (par. 14-22), the programmable parameters of the adjustable frequency drive return to their default settings.

Intermittent Duty Cycle An intermittent duty rating refers to a sequence of duty cycles. Each cycle consists of an on-load and an off-load period. The operation can be either a periodic or non-periodic duty.

LCP The Local Control Panel (LCP) makes up a complete interface for control and programming of the adjustable frequency drive. The control panel is detachable and can be installed up to 9.8 ft (3 meters) from the adjustable frequency drive, i.e. in a front panel by means of the installation kit option. The local control panel is available in two versions:

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VLT® HVAC Drive Design Guide

– Numerical LCP101 (NLCP) – Graphical LCP102 (GLCP)
1
lsb Least significant bit.
MCM Short for Mille Circular Mil, an American measuring unit for cable cross- section. 1 MCM 0.00079 in.2 (0.5067 mm2).
msb Most significant bit.
NLCP Numerical Local Control Panel LCP101
Online/Offline Parameters Changes to online parameters are activated immediately after the data value is changed. Changes to offline parameters are not activated until you enter [OK] on the LCP.
PID Controller The PID controller maintains the desired speed, pressure, temperature, etc. by adjusting the output frequency to match the varying load.
RCD Residual Current Device.
Set-up You can save parameter settings in four set-ups. Change between the four parameter set-ups and edit one while another set-up is active.
SFAVM Switching pattern called Stator Flux oriented Asynchronous V ector M odulation (par. 14-00).
Slip Compensation The adjustable frequency drive compensates for the motor slip by giving the frequency a supplement that follows the measured motor load, thus keeping the motor speed almost constant.
Smart Logic Control (SLC) The SLC is a sequence of user-defined actions executed when the associated user-defined events are evaluated as true by the SLC.

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Thermistor: A temperature-dependent resistor placed where the temperature is to be monitored (adjustable frequency drive or motor).
1
Trip A state entered in fault situations, such as when the adjustable frequency drive is subject to an overtemperature, or when the adjustable frequency drive is protecting the motor, process or mechanism. Restart is prevented until the cause of the fault has rectified and the trip state is cancelled by activating reset, or, in some cases, by programming an automatic reset. Trip may not be used as a personal safety measure.
Trip-Locked A state entered in fault situations when the adjustable frequency drive is protecting itself and requiring physical intervention, such as when the adjustable frequency drive is subject to a short circuit on the output. A locked trip can only be cancelled by cutting off line power, removing the cause of the fault and reconnecting the adjustable frequency drive. Restart is prevented until the trip state is cancelled by activating reset or, in some cases, by being programmed to reset automatically. The trip-lock function may not be used as a personal safety measure.
VT Characteristics Variable torque characteristics used for pumps and fans.
VVCplus Compared with standard voltage/frequency ratio control, voltage vector control (VVCplus) improves the dynamics and the stability, both when the speed reference is changed and in relation to the load torque.
60° AVM Switching pattern called 60°Asynchronous Vector Modulation (See par. 14-00).

1.1.7 Power Factor
The power factor is the relation between I1 and IRMS. The power factor for 3-phase control:

Power factor =

3 × U × I1 × COS 3 × U × IRMS

=

I1

× cos1 IRMS

=

I1 IRMS

since

cos1 = 1

The power factor indicates to which extent the adjustable frequency drive imposes a load on the line supply. The lower the power factor, the higher the IRMS for the same kW performance.

IRMS =

I

2 1

I

2 5

I

2 7

. .

I

2 n

In addition, a high power factor indicates that the different harmonic currents are low. The adjustable frequency drive’s built-in DC coils produce a high power factor, which minimizes the imposed load on the line power supply.

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VLT® HVAC Drive Design Guide

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Introduction to the VLT HVAC Drive

2 Introduction to the VLT HVAC Drive

2.1 Safety

2.1.1 Safety note

2

The voltage of the adjustable frequency drive is dangerous whenever connected to line power. Incorrect installation of the motor, adjustable frequency drive or serial communication bus may cause damage to the equipment, serious personal injury or death. Consequently, the instructions in this manual, as well as national and local rules and safety regulations, must be followed.

Safety Regulations 1. The adjustable frequency drive must be disconnected from line power if repair work is to be carried out. Make sure that the line supply has been disconnected and that the necessary time has passed before removing motor and line plugs. 2. The [STOP/RESET] key on the control panel of the adjustable frequency drive does not disconnect the equipment from line power and is thus not to be used as a safety switch. 3. Correct protective grounding of the equipment must be established, the user must be protected against supply voltage, and the motor must be protected against overload in accordance with applicable national and local regulations. 4. The ground leakage currents are higher than 3.5 mA. 5. Protection against motor overload is set by par. 1-90 Motor Thermal Protection. If this function is desired, set par. 1-90 to data value [ETR trip] (default value) or data value [ETR warning]. Note: The function is initialized at 1.16 x rated motor current and rated motor frequency. For the North American market: The ETR functions provide class 20 motor overload protection in accordance with NEC. 6. Do not remove the plugs for the motor and line supply while the adjustable frequency drive is connected to line power. Make sure that the line supply has been disconnected and that the necessary time has passed before removing motor and line plugs. 7. Please note that the adjustable frequency drive has more voltage inputs than L1, L2 and L3 when load sharing (linking of DC intermediate circuit) and external 24 V DC have been installed. Make sure that all voltage inputs have been disconnected and that the necessary time has passed before commencing repair work.
Installation at High Altitudes
At altitudes higher than 6,600 feet [2 km], please contact Danfoss Drives regarding PELV.

Warning against Unintended Start 1. The motor can be brought to a stop by means of digital commands, bus commands, references or a local stop while the adjustable frequency drive is connected to line power. If personal safety considerations make it necessary to ensure that no unintended start occurs, these stop functions are not sufficient. 2. While parameters are being changed, the motor may start. Consequently, the stop key [STOP/RESET] must always be activated, after which data can be modified. 3. A motor that has been stopped may start if faults occur in the electronics of the adjustable frequency drive, or if a temporary overload or a fault in the supply line or the motor connection ceases.
Warning: Touching the electrical parts may be fatal – even after the equipment has been disconnected from line power.
Also, make sure that other voltage inputs have been disconnected, such as external 24 V DC, load sharing (linkage of DC intermediate circuit), as well as the motor connection for kinetic backup. Refer to VLT® HVAC Drive Instruction Manual MG.11.Ax.yy for further safety guidelines.

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VLT® HVAC Drive Design Guide

2.1.2 Caution

2

Caution
The adjustable frequency drive DC link capacitors remain charged after power has been disconnected. To avoid the risk of electrical shock, disconnect the adjustable frequency drive from the line power before performing maintenance procedures. Wait at least as long as follows before servicing the adjustable frequency drive:

Voltage 200-240 V 380-480 V
525-600 V

Minimum Waiting Time

4 min.

15 min.

20 min.

30 min.

1.5-5 hp [1.1-3.7 kW] 7.5-60 hp [5.5-45 kW]

150-300 hp [110-200 1.5-10 hp [1.1-7.5 kW] 15-125 hp [11-90 kW] kW]

1.5-10 hp [1.1-7.5 kW]

150-350 hp [110-250 450-750 hp [315-560

kW]

kW]

Be aware that there may be high voltage on the DC link even when the LEDs are turned off.

40 min.
350-600 hp [250-450 kW]

2.1.3 Disposal Instructions

Equipment containing electrical components may not be disposed of together with domestic waste. It must be collected separately as electrical and electronic waste according to local and currently valid legislation.

2.2 CE labeling
2.2.1 CE Conformity and Labeling
What is CE Conformity and Labeling? The purpose of CE labeling is to avoid technical trade obstacles within the EFTA and the EU. The EU has introduced the CE label as a simple way of showing whether a product complies with the relevant EU directives. The CE label says nothing about the specifications or quality of the product. Adjustable frequency drives are regulated by three EU directives: The machinery directive (98/37/EEC) All machines with critical moving parts are covered by the Machinery Directive of January 1, 1995. Since an adjustable frequency drive is largely electrical, it does not fall under the Machinery Directive. However, if an adjustable frequency drive is supplied for use in a machine, we provide information on its safety aspects in the manufacturer’s declaration. The low-voltage directive (73/23/EEC) Adjustable frequency drives must be CE-labeled in accordance with the Low-voltage Directive of January 1, 1997. The directive applies to all electrical equipment and appliances used in the 50-1000 V AC and the 75-1500 V DC voltage ranges. Danfoss uses CE labels in accordance with the directive and will issue a declaration of conformity upon request.

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2 Introduction to the VLT HVAC Drive

The EMC directive (89/336/EEC)

EMC is short for electromagnetic compatibility. The presence of electromagnetic compatibility means that the mutual interference between different

components/appliances does not affect the way the appliances work.

The EMC directive came into effect January 1, 1996. Danfoss uses CE labels in accordance with the directive and will issue a declaration of conformity

upon request. To carry out EMC-correct installation, see the instructions in this Design Guide. In addition, we specify the standards with which our products

comply. We offer the filters presented in the specifications and provide other types of assistance to ensure the optimum EMC result.

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The adjustable frequency drive is most often used by professionals of the trade as a complex component forming part of a larger appliance, system or installation. It must be noted that the responsibility for the final EMC properties of the appliance, system or installation rests with the installer.

2.2.2 What Is Covered
The EU “Guidelines on the Application of Council Directive 89/336/EEC” outline three typical situations of using an adjustable frequency drive. See below for EMC coverage and CE labeling.
1. The adjustable frequency drive is sold directly to the end-consumer. For example, it may be sold to a DIY market. The end-consumer is a layman. He installs the adjustable frequency drive himself for use with a hobby machine, a kitchen appliance, etc. For such applications, the adjustable frequency drive must be CE-labeled in accordance with the EMC directive.
2. The adjustable frequency drive is sold for installation in a plant. The plant is built up by professionals of the trade. It could be a production plant or a heating/ventilation plant designed and installed by professionals of the trade. Neither the adjustable frequency drive nor the finished plant must be CE-labeled under the EMC directive. However, the unit must comply with the basic EMC requirements of the directive. This is ensured by using components, appliances and systems that are CE-labeled under the EMC directive.
3. The adjustable frequency drive is sold as part of a complete system. The system is being marketed as complete and could, for example, be an air- conditioning system. The complete system must be CE-labeled in accordance with the EMC directive. The manufacturer can ensure CElabeling under the EMC directive either by using CE-labeled components or by testing the EMC of the system. If he chooses to use only CElabeled components, he does not have to test the entire system.
2.2.3 Danfoss VLT Adjustable Frequency Drive and CE Labeling
CE labeling is a positive feature when used for its original purpose, i.e. to facilitate trade within the EU and EFTA.
However, CE labeling may cover many different specifications. Thus, you must check what a given CE label specifically covers.
The covered specifications can be very different and a CE label may therefore give the installer a false sense of security when using an adjustable frequency drive as a component in a system or an appliance.
Danfoss CE labels the adjustable frequency drives in accordance with the low- voltage directive. This means that if the adjustable frequency drive is installed correctly, we guarantee compliance with the low-voltage directive. Danfoss issues a declaration of conformity that confirms our CE labeling in accordance with the low-voltage directive.
The CE label also applies to the EMC directive provided that the instructions for EMC-correct installation and filtering are followed. On this basis, a declaration of conformity in accordance with the EMC directive is issued.
The Design Guide offers detailed instructions for installation to ensure EMC- correct installation. Furthermore, Danfoss specifies which our different products comply with.
Danfoss gladly provides other types of assistance that can help you obtain the best EMC result.

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VLT® HVAC Drive Design Guide

2.2.4 Compliance with EMC Directive 89/336/EEC

As mentioned, the adjustable frequency drive is mostly used by professionals of the trade as a complex component forming part of a larger appliance,

system or installation. It must be noted that the responsibility for the final EMC properties of the appliance, system or installation rests with the installer.

To assist the installer, Danfoss has prepared EMC installation guidelines for the Power Drive system. The standards and test levels stated for power drive

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systems are complied with, provided that the EMC-correct instructions for installation are followed; see the section EMC Immunity.

2.3 Air humidity
2.3.1 Air Humidity
The adjustable frequency drive has been designed to meet the IEC/EN 60068-2-3 standard, EN 50178 pkt. 9.4.2.2 at 122°F [50°C].

2.4 Aggressive Environments
An adjustable frequency drive contains a large number of mechanical and electronic components. All are vulnerable to environmental effects to some extent.
The adjustable frequency drive should not be installed in environments with airborne liquids, particles or gases capable of affecting and damaging the electronic components. Failure to take the necessary protective measures increases the risk of stoppages, thus reducing the life of the adjustable frequency drive.
Liquids can be carried through the air and condense in the adjustable frequency drive and may cause corrosion of components and metal parts. Steam, oil and salt water may cause corrosion of components and metal parts. In such environments, use equipment with enclosure rating IP 55. As an extra protection, coated printet circuit boards can be ordered as an option.
Airborne particles such as dust may cause mechanical, electrical or thermal failure in the adjustable frequency drive. A typical indicator of excessive levels of airborne particles is the presence of dust particles around the adjustable frequency drive fan. In very dusty environments, use equipment with enclosure rating IP 55 or a cabinet for IP 00/IP 20/TYPE 1 equipment.
In environments with high temperatures and humidity, corrosive gases such as sulfur, nitrogen and chlorine compounds will cause chemical processes on the adjustable frequency drive components.
Such chemical reactions will rapidly affect and damage the electronic components. In such environments, mount the equipment in a cabinet with fresh air ventilation, keeping aggressive gases away from the adjustable frequency drive. An extra protection in such areas is a coating of the printed circuit boards, which can be ordered as an option.
NOTE! Mounting adjustable frequency drives in aggressive environments increases the risk of stoppages and considerably reduces the life of the drive.
Before installing the adjustable frequency drive, check the ambient air for liquids, particles and gases. This is done by observing existing installations in this environment. A typical indicator of harmful airborne liquids is the presence of water or oil on metal parts, or the corrosion of metal parts.
Excessive dust particle levels are often found on installation cabinets and existing electrical installations. One indicator of aggressive airborne gases is the blackening of copper rails and cable ends on existing installations.

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2 Introduction to the VLT HVAC Drive

2.5 Vibration and shock

The adjustable frequency drive has been tested according to the procedure based on the shown standards:

The adjustable frequency drive complies with requirements that exist for units mounted on the walls and floors of production premises, as well as in

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panels bolted to walls or floors.

IEC/EN 60068-2-6: IEC/EN 60068-2-64:

Vibration (sinusoidal) – 1970 Vibration, broad-band random

2.6 Advantages
2.6.1 Why use an adjustable frequency drive for controlling fans and pumps?
An adjustable frequency drive takes advantage of the fact that centrifugal fans and pumps follow the laws of proportionality for such fans and pumps. For further information, see The Laws of Proportionality text.

2.6.2 The clear advantage – energy savings
The very clear advantage of using an adjustable frequency drive for controlling the speed of fans or pumps lies in the electricity savings. Compared to alternative control systems and technologies, an adjustable frequency drive is the optimum energy control system for controlling fan and pump systems.

2.6.3 Example of energy savings
As can be seen from the figure (the laws of proportionality), the flow is controlled by changing the rpm. By reducing the rated speed by only 20%, the flow is also reduced by 20%. This is because the flow is directly proportional to the rpm. The consumption of electricity, however, is reduced by 50%. If the system in question only needs to be able to supply a flow corresponding to 100% a few days each year, while the average is below 80% of the rated flow for the remainder of the year, the amount of energy saved is even greater than 50%.

The laws of proportionality The figure below describes the dependence of flow, pressure and power consumption on rpm.

Q = Flow Q1 = Rated flow Q2 = Reduced flow

P = Power P1 = Rated power P2 = Reduced power

H = Pressure H1 = Rated pressure H2 = Reduced pressure

n = Speed regulation n1 = Rated speed n2 = Reduced speed

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VLT® HVAC Drive Design Guide

Flow :

Q1 Q2

=

n1 n2

( ) Pressure :

H1 H2

=

n1 2 n2

( ) Power :

P1 P2

=

n1 3 n2

2.6.4 Example with varying flow over 1 year
The example below is calculated on the basis of pump characteristics obtained from a pump datasheet. The result obtained shows energy savings in excess of 50% at the given flow distribution over a year. The pay back period depends on the price per kwh and the price of the adjustable frequency drive. In this example, it is less than a year when compared with valves and constant speed.

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Pump characteristics

2 Introduction to the VLT HVAC Drive
Energy savings Pshaft=Pshaft output
2
Flow distribution over 1 year

m3/h
350 300 250 200 150 100

Distribution

%

Hours

5

438

15

1314

20

1752

20

1752

20

1752

20

1752

100

8760

Valve regulation

Power

Consumption

A1 – B1

kWh

42.5

18,615

38.5

50,589

35.0

61,320

31.5

55,188

28.0

49,056

23.0

40,296

275,064

Adjustable frequency drive control

Power

Consumption

A1 – C1

kWh

42.5

18,615

29.0

38,106

18.5

32,412

11.5

20,148

6.5

11,388

3.5

6,132

26,801

2.6.5 Better control
If an adjustable frequency drive is used for controlling the flow or pressure of a system, improved control is obtained. An adjustable frequency drive can vary the speed of the fan or pump, thereby obtaining variable control of flow and pressure. Furthermore, an adjustable frequency drive can quickly adapt the speed of the fan or pump to new flow or pressure conditions in the system. Simple control of process (flow, level or pressure) utilizing the built-in PID control.
2.6.6 Cos compensation
Generally speaking, an adjustable frequency drive with a cos of 1 provides power factor correction for the cos of the motor, which means that there is no need to make allowance for the cos of the motor when sizing the power factor correction unit.

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2 Introduction to the VLT HVAC Drive

VLT® HVAC Drive Design Guide

2.6.7 Star/delta starter or soft-starter not required

When larger motors are started, it is necessary in many countries to use equipment that limits the start-up current. In more traditional systems, a star/

2

delta starter or soft-starter is widely used. Such motor starters are not required if an adjustable frequency drive is used.

As illustrated in the figure below, an adjustable frequency drive does not consume more than rated current.

1 = VLT HVAC Drive 2 = Star/delta starter
3 = Soft-starter 4 = Start directly on line power

2.6.8 The cost of using an adjustable frequency drive is not significantly high.
The example on the following page shows that a lot of extra equipment is not required when an adjustable frequency drive is used. It is possible to calculate the cost of installing the two different systems. In the example, the two systems can be established at roughly the same price.

2.6.9 Without an adjustable frequency drive

The figure shows a fan system made in the traditional way.

D.D.C. V.A.V.

=

Direct Digital Control

=

Variable Air Volume

Sensor P

=

Pressure

E.M.S. Sensor T

= Energy Management system = Temperature

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2 Introduction to the VLT HVAC Drive
2

2.6.10 With an adjustable frequency drive
The figure shows a fan system controlled by adjustable frequency drives.

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2 Introduction to the VLT HVAC Drive

VLT® HVAC Drive Design Guide

2.6.11 Application examples
The next few pages give typical examples of applications within HVAC. If you would like to receive further information about a given application, please ask your Danfoss supplier for an information sheet that gives a full description of the application.
2 Variable Air Volume Ask for The Drive to…Improving Variable Air Volume Ventilation Systems MN.60.A1.02
Constant Air Volume Ask for The Drive to…Improving Constant Air Volume Ventilation Systems MN.60.B1.02
Cooling Tower Fan Ask for The Drive to…Improving Fan Control on Cooling Towers MN.60.C1.02
Condenser pumps Ask for The Drive to…Improving Condenser Water Pumping Systems MN.60.F1.02
Primary pumps Ask for The Drive to…Improve Your Primary Pumping in Primary/Secondary Pumping Systems MN.60.D1.02
Secondary pumps Ask for The Drive to…Improve Your Secondary Pumping in Primary/Secondary Pumping Systems MN.60.E1.02

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2 Introduction to the VLT HVAC Drive

2.6.12 Variable Air Volume

VAV or Variable Air Volume systems, are used to control both the ventilation and temperature to satisfy the requirements of a building. Central VAV

systems are considered to be the most energy efficient method to air condition buildings. By designing central systems instead of distributed systems,

greater efficiency can be obtained.

This greater efficiency is a result of utilizing larger fans and larger chillers, which have much higher efficiency rates than small motors and distributed air-

2

cooled chillers. Savings are also a result of decreased maintenance requirements.

2.6.13 The VLT solution
While dampers and IGVs work to maintain a constant pressure in the ductwork, an adjustable frequency drive solution saves much more energy and reduces the complexity of the installation. Instead of creating an artificial pressure drop or causing a decrease in fan efficiency, the adjustable frequency drive decreases the speed of the fan to provide the flow and pressure required by the system. Centrifugal devices such as fans behave according to the centrifugal laws. This means the fans decrease the pressure and flow they produce as their speed is reduced. Their power consumption is thereby significantly reduced. The return fan is frequently controlled to maintain a fixed difference in airflow between the supply and return. The advanced PID controller of the VLT HVAC Drive can be used to eliminate the need for additional controllers.

Cooling coil

Heating coil

Filter

D1

D2

D3

Pressure signal
Supply fan
3

VAV boxes T

Pressure Flow transmitter

Return fan
3

Flow

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VLT® HVAC Drive Design Guide

2.6.14 Constant Air Volume

CAV, or Constant Air Volume systems, are central ventilation systems usually used to supply large common zones with the minimum amounts of fresh

tempered air. They preceded VAV systems and therefore are found in older, multi-zoned commercial buildings as well. These systems preheat certain

amounts of fresh air utilizing Air Handling Units (AHUs) with a heating coil, and many are also used to air condition buildings and have a cooling coil. Fan

2

coil units are frequently used to assist in the heating and cooling requirements in the individual zones.

2.6.15 The VLT solution
With an adjustable frequency drive, significant energy savings can be obtained while maintaining decent control of the building. Temperature sensors or CO2 sensors can be used as feedback signals to adjustable frequency drives. Whether controlling temperature, air quality, or both, a CAV system can be controlled to operate based on actual building conditions. As the number of people in the controlled area decreases, the need for fresh air decreases. The CO2 sensor detects lower levels and decreases the speed of the supply fans. The return fan modulates to maintain a static pressure setpoint or fixed difference between the supply and return air flows.

With temperature control (especially used in air conditioning systems), as the outside temperature varies and the number of people in the controlled zone changes, different cooling requirements arise. As the temperature decreases below the setpoint, the supply fan can decrease its speed. The return fan modulates to maintain a static pressure setpoint. By decreasing the air flow, energy used to heat or cool the fresh air is also reduced, adding further savings. Several features of the Danfoss HVAC dedicated adjustable frequency drive, the VLT® HVAC Drive can be utilized to improve the performance of your CAV system. One concern of controlling a ventilation system is poor air quality. The programmable minimum frequency can be set to maintain a minimum amount of supply air, regardless of the feedback or reference signal. The adjustable frequency drive also includes a 3-zone, 3-setpoint PID controller which allows monitoring of both temperature and air quality. Even if the temperature requirement is satisfied, the drive will maintain enough supply air to satisfy the air quality sensor. The controller is capable of monitoring and comparing two feedback signals to control the return fan by maintaining a fixed differential air flow between the supply and return ducts as well.

Cooling coil

Heating coil

Filter

D1

D2

D3

Temperature signal Supply fan
Pressure signal Return fan

Temperature transmitter
Pressure transmitter

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2 Introduction to the VLT HVAC Drive

2.6.16 Cooling Tower Fan

Cooling tower fans are used to cool condenser water in water-cooled chiller systems. Water-cooled chillers provide the most efficient means of creating

chilled water. They are as much as 20% more efficient than air-cooled chillers. Depending on climate, cooling towers are often the most energy efficient

method of cooling the condenser water from chillers.

They cool the condenser water by evaporation.

2

The condenser water is sprayed into the cooling tower, onto the cooling tower’s “fill” to increase its surface area. The tower fan blows air through the

fill and sprays water to aid in the evaporation. Evaporation removes energy from the water, thus dropping its temperature. The cooled water collects in

the cooling towers basin, where it is pumped back into the chiller’s condenser, and the cycle is then repeated.

2.6.17 The VLT solution
With an adjustable frequency drive, the cooling towers fans can be set to the speed required to maintain the condenser water temperature. The adjustable frequency drives can also be used to turn the fan on and off as needed.
Several features of the Danfoss HVAC dedicated drive, the VLT HVAC Drive can be utilized to improve the performance of your cooling tower fan application. As the cooling tower fans drop below a certain speed, the effect the fan has on cooling the water becomes insignificant. Also, when utilizing a gear-box to frequency control the tower fan, a minimum speed of 40-50% may be required. The customer programmable minimum frequency setting is available to maintain this minimum frequency even as the feedback or speed reference calls for lower speeds.
Another standard feature is the “sleep” mode, which allows the user to program the adjustable frequency drive to stop the fan until a higher speed is required. Additionally, some cooling tower fans have undesireable frequencies that may cause vibrations. These frequencies can easily be avoided by programming the bypass frequency ranges in the adjustable frequency drive.

Water Inlet

BASIN

Temperature Sensor

Water Outlet

Conderser Water pump

CHILLER

Supply

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VLT® HVAC Drive Design Guide

2.6.18 Condenser pumps
Condenser water pumps are primarily used to circulate water through the condenser section of water cooled chillers and their associated cooling tower. The condenser water absorbs the heat from the chiller’s condenser section and releases it into the atmosphere in the cooling tower. These systems are used to provide the most efficient means of creating chilled water, and they are as much as 20% more efficient than air cooled chillers.
2
2.6.19 The VLT solution
Adjustable frequency drives can be added to condenser water pumps instead of balancing the pumps with a throttling valve or trimming the pump impeller.
Using an adjustable frequency drive instead of a throttling valve simply saves the energy that would have been absorbed by the valve. This can amount to savings of 15-20% or more. Trimming the pump impeller is irreversible, thus if the conditions change and higher flow is required the impeller must be replaced.

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2 Introduction to the VLT HVAC Drive

2.6.20 Primary pumps

Primary pumps in a primary/secondary pumping system can be used to maintain a constant flow through devices that encounter operation or control

difficulties when exposed to variable flow. The primary/secondary pumping technique decouples the “primary” production loop from the “secondary”

distribution loop. This allows devices such as chillers to obtain constant design flow and operate properly while allowing the rest of the system to vary in

flow.

2

As the evaporator flow rate decreases in a chiller, the chilled water begins to become overly chilled. As this happens, the chiller attempts to decrease its cooling capacity. If the flow rate drops far enough, or too quickly, the chiller cannot shed its load sufficiently and the chiller’s low evaporator temperature safety trips the chiller, requiring a manual reset. This situation is common in large installations, especially when two or more chillers are installed in parallel and primary/secondary pumping is not utilized.

2.6.21 The VLT solution
Depending on the size of the system and the size of the primary loop, the energy consumption of the primary loop can become substantial. An adjustable frequency drive can be added to the primary system to replace the throttling valve and/or trimming of the impellers, leading to reduced operating expenses. Two control methods are common:
The first method uses a flow meter. Because the desired flow rate is known and constant, a flow meter installed at the discharge of each chiller can be used to control the pump directly. Using the built-in PID controller, the adjustable frequency drive will always maintain the appropriate flow rate, even compensating for the changing resistance in the primary piping loop as chillers and their pumps are staged on and off.
The other method is local speed determination. The operator simply decreases the output frequency until the design flow rate is achieved.

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VLT® HVAC Drive Design Guide

Using a adjustable frequency drive to decrease the pump speed is very similar to trimming the pump impeller, except it doesn’t require any labor and

the pump efficiency remains higher. The balancing contractor simply decreases the speed of the pump until the proper flow rate is achieved and leaves

the speed fixed. The pump will operate at this speed any time the chiller is staged on. Because the primary loop doesn’t have control valves or other

devices that can cause the system curve to change, and because the variance due to staging pumps and chillers on and off is usually small, this fixed

speed will remain appropriate. In the event the flow rate needs to be increased later in the systems life, the adjustable frequency drive can simply increase

2

the pump speed instead of requiring a new pump impeller.

Flowmeter
F

Flowmeter
F

CHILLER CHILLER

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2 Introduction to the VLT HVAC Drive

2.6.22 Secondary pumps

Secondary pumps in a primary/secondary chilled water pumping system are used to distribute the chilled water to the loads from the primary production

loop. The primary/secondary pumping system is used to hydraulically decouple one piping loop from another. In this case, the primary pump is used to

maintain a constant flow through the chillers while allowing the secondary pumps to vary in flow, increase control and save energy.

If the primary/secondary design concept is not used and a variable volume system is designed, the chiller cannot shed its load properly when the flow

2

rate drops far enough or too quickly. The chiller’s low evaporator temperature safety then trips the chiller, requiring a manual reset. This situation is

common in large installations, especially when two or more chillers are installed in parallel.

2.6.23 The VLT solution
While the primary-secondary system with two-way valves improves energy savings and eases system control problems, the true energy savings and control potential is realized by adding adjustable frequency drives. With the proper sensor location, the addition of adjustable frequency drives allows the pumps to vary their speed to follow the system curve instead of the pump curve. This results in the elimination of wasted energy and eliminates most of the over- pressurization to which two-way valves can be subjected. As the monitored loads are reached, the two-way valves close down. This increases the differential pressure measured across the load and two-way valve. As this differential pressure starts to rise, the pump is slowed to maintain the control head also called setpoint value. This setpoint value is calculated by adding the pressure drop of the load and the two-way valve under design conditions.

NOTE! Please note that when running multiple pumps in parallel, they must run at the same speed to maximize energy savings, either with individual dedicated drives or one drive running multiple pumps in parallel.

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VLT® HVAC Drive Design Guide

2.7 VLT HVAC Controls

2.7.1 Control Principle

2

An adjustable frequency drive rectifies AC voltage from line into DC voltage, after which DC voltage is converted into an AC current with a variable

amplitude and frequency.

The motor is supplied with variable voltage / current and frequency, which enables infinitely variable speed control of three-phased, standard AC motors.

2.7.2 Control Structure
Control structure in open-loop and closed-loop configurations:

In the configuration shown in the illustration above, par. 1-00 is set to Open-loop [0]. The resulting reference from the reference handling system is received and fed through the ramp limitation and speed limitation before being sent to the motor control. The output of the motor control is then limited by the maximum frequency limit.
Select Closed-loop [3] in par. 1-00 to use the PID controller for closed-loop control of, e.g., flow, level or pressure in the controlled application. The PID parameters are located in par. group 20-**.
2.7.3 Local (Hand On) and Remote (Auto On) Control
The adjustable frequency drive can be operated manually via the local control panel (LCP) or remotely via analog and digital inputs and serial bus. If allowed in par. 0-40, 0-41, 0-42, and 0-43, it is possible to start and stop the adjustable frequency drive via the LCP using the [Hand ON] and [Off] keys. Alarms can be reset via the [RESET] key. After pressing the [Hand On] key, the adjustable frequency drive goes into hand mode and follows (as default) the local reference set by using the LCP arrow keys.

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2 Introduction to the VLT HVAC Drive

After pressing the [Auto On] key, the adjustable frequency drive goes into auto mode and follows (as default) the remote reference. In this mode, it is possible to control the adjustable frequency drive via the digital inputs and various serial interfaces (RS-485, USB, or an optional serial communication bus). See more about starting, stopping, changing ramps and parameter set-ups, etc. in par. group 5-1 (digital inputs) or par. group 8-5 (serial communication).

130BP046.10

2

Active Reference and Configuration Mode
The active reference can be either the local reference or the remote reference.
In par. 3-13 Reference Site, the local reference can be permanently selected by selecting Local [2]. To permanently select the remote reference, select Remote [1]. By selecting Linked to Hand/Auto [0] (default), the reference site will depend on which mode is active. (Hand Mode or Auto Mode).

Hand Off Auto LCP Keys Hand Hand -> Off Auto Auto -> Off All keys All keys

Reference Site Par. 3-13
Linked to Hand/Auto Linked to Hand/Auto Linked to Hand/Auto Linked to Hand/Auto Local Remote

Active Reference
Local Local Remote Remote Local Remote

The table shows under which conditions either the local reference or the remote reference is active. One of them is always active, but both cannot be active at the same time.

Par. 1-00 Configuration Mode determines what kind of application control principle (i.e., open-loop or closed-loop) is used when the remote reference is active (see table above for the conditions).

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2 Introduction to the VLT HVAC Drive
Reference Handling – Local Reference
2

VLT® HVAC Drive Design Guide

2.8 PID
2.8.1 Closed-loop (PID) Controller
The drive’s closed-loop controller allows the drive to become an integral part of the controlled system. The drive receives a feedback signal from a sensor in the system. It then compares this feedback to a setpoint reference value and determines the error, if any, between these two signals. It then adjusts the speed of the motor to correct this error.
For example, consider a ventilation system where the speed of the supply fan is to be controlled so that the static pressure in the duct is constant. The desired static pressure value is supplied to the drive as the setpoint reference. A static pressure sensor measures the actual static pressure in the duct and supplies this to the drive as a feedback signal. If the feedback signal is greater than the setpoint reference, the drive will slow down to reduce the pressure. In a similar way, if the duct pressure is lower than the setpoint reference, the drive will automatically speed up to increase the pressure provided by the fan.

NOTE! While the default values for the drive’s closed-loop controller will often provide satisfactory performance, the control of the system can often be optimized by adjusting some of the closed-loop controller’s parameters.
The figure is a block diagram of the drive’s closed-loop controller. The details of the reference handling block and feedback handling block are described in their respective sections below.

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2 Introduction to the VLT HVAC Drive

The following parameters are relevant for a simple PID control application:

Parameter

Description of function

Feedback 1 Source

par. 20-00

Select the source for Feedback 1. This is most commonly an analog input, but other sources are

also available. Use the scaling of this input to provide the appropriate values for this signal. By default, Analog Input 54 is the default source for Feedback 1.

2

Reference/Feedback Unit

par 20-12

Select the unit for the setpoint referenceand feedback for the drive’s closed- loop controller. Note:

Because a conversion can be applied to the feedback signal before it is used by the closed-loop

controller, the reference/feedback unit (par. 20-12) may not be the same as the feedback source

unit (par. 20-02, 20-05 and 20-08).

PID Normal/Inverse Control par. 20-81

Select Normal [0] if the motor’s speed should decrease when the feedback is greater than the

setpoint reference. Select Inverse [1] if the motor’s speed should increase when the feedback

is greater than the setpoint reference.

PID Proportional Gain

par. 20-93

This parameter adjusts the output of the drive’s closed-loop control based on the error between

the feedback and the setpoint reference. Quick controller response is obtained when this value

is large. However, if a value that is too large is used, the drive’s output frequency may become

unstable.

PID Integral Time

par. 20-94

Over time, the integrator adds (integrates) the error between the feedback and the setpoint

reference. This is required to ensure that the error approaches zero. Quick controller response

is obtained when this value is small. However, if a value that is too small is used, the drive’s

output frequency may become unstable. A setting of 10,000 s disables the integrator.

This table summarizes the parameters that are needed to set up the drive’s closed-loop controller when a single feedback signal with no conversion is compared to a single setpoint. This is the most common type of closed-loop controller.

2.8.2 Closed-loop Control Relevant Parameters
The drive’s closed-loop controller is capable of handling more complex applications, such as situations where a conversion function is applied to the feedback signal or situations where multiple feedback signals and/or setpoint references are used. The table below summarizes the additional parameters that may be useful in such applications.

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VLT® HVAC Drive Design Guide

Parameter Feedback 2 Source Feedback 3 Source

2

Feedback 1 Conversion

Feedback 2 Conversion

Feedback 3 Conversion

Feedback 1 Source Unit Feedback 2 Source Unit Feedback 3 Source Unit Feedback Function

Setpoint 1 Setpoint 2 Setpoint 3 Refrigerant

par. 20-03 par. 20-06
par. 20-01 par. 20-04 par. 20-07
par. 20-02 par. 20-05 par. 20-08 par. 20-20
par. 20-21 par. 20-22 par. 20-23 par. 20-30

Description of function Select the source, if any, for Feedback 2 or 3. This is most commonly a drive analog input, but other sources are also available. Par. 20-20 determines how multiple feedback signals will be processed by the drive’s closed-loop controller. By default, these are set to No function [0]. These are used to convert the feedback signal from one type to another, for example from pressure to flow or from pressure to temperature (for compressor applications). If Pressure to temperature [2] is selected, the refrigerant must be specified in par. Group 20-3, Feedback Adv. Conv. By default, these are set to Linear [0]. Select the unit for a feedback source prior to any conversions. This is used for display purposes only. This parameter is only available when using Pressure to Temperature feedback conversion. When multiple feedbacks or setpoints are used, this determines how they will be processed by the drive’s closed-loop controller. These setpoints can be used to provide a setpoint reference to the drive’s closed-loop controller. Par. 20-20 determines how multiple setpoint references will be processed. Any other references that are activated in par. group 3-1 will add to these values. If any feedback conversion (par. 20-01, 20-04 or 20-07) is set to Pressure to Temperature [2], the refrigerant type must be selected here. If the refrigerant used is not listed here, select User defined [7] and specify the characteristics of the refrigerant in par. 20-31, 20-32 and 20-33.

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2 Introduction to the VLT HVAC Drive

Parameter Custom Refrigerant A1 Custom Refrigerant A2 Custom Refrigerant A3 PID Start Speed [RPM] PID Start Speed [Hz] On Reference Bandwidth PID Anti Windup
PID Differentiation Time
PID Diff. Gain Limit
Low-pass Filter Time: Analog Input 53 Analog Input 54 Digital (pulse) input 29 Digital (pulse) input 33

Description of function

par. 20-31

When par. 20-30 is set to User defined [7], these parameters are used to define the

par. 20-32

value of coefficients A1, A2 and A3 in the conversion equation:

par. 20-33

Temperature

=

A2 (ln(pressure + 1) – A1)

– A3

par. 20-82

The parameter that is visible will depend on the setting of par. 0-02, Motor Speed Unit.

2

par. 20-83

In some applications, and after a start command, it is important to quickly ramp the

motor up to a pre-determined speed before activating the drive’s closed-loop controller.

This parameter defines that starting speed.

par. 20-84

This determines how close the feedback must be to the setpoint reference for the drive

to indicate that the feedback is equal to the setpoint.

par. 20-91

On [1] effectively disables the closed-loop controller’s integral function when it is not

possible to adjust the output frequency of the drive to correct the error. This allows the

controller to respond more quickly once it can again control the system. Off [0] disables

this function, making the integral function stay active continuously.

par. 20-95

This controls the output of the drive’s closed-loop controller based on the rate of change

of feedback. While this can provide fast controller response, such response is seldom

needed in HVAC systems. The default value for this parameter is Off, or 0.00 s.

par. 20-96

Because the differentiator responds to the rate of change of the feedback, a rapid

change can cause a large, undesired change in the output of the controller. This is used

to limit the maximum effect of the differentiator. This is not active when par. 20-95 is

set to Off.

par. 6-16

This is used to filter out high frequency noise from the feedback signal. The value en-

par. 6-26

tered here is the time constant for the low-pass filter. The cut-off frequency in Hz can

par. 5-54

be calculated as follows:

par. 5-59

Fcut-off

=

1 2T low-pass

Variations in the feedback signal whose frequency is below Fcut-off will be used by the

drive’s closed-loop controller, while variations at a higher frequency are considered to

be noise and will be attenuated. Large values of Low-pass Filter Time will provide more

filtering, but may cause the controller to not respond to actual variations in the feedback

signal.

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2 Introduction to the VLT HVAC Drive 2.8.3 Example of Closed-loop PID Control
The following is an example of a closed-loop control for a ventilation system:
2

VLT® HVAC Drive Design Guide

In a ventilation system, the temperature is to be maintained at a constant value. The desired temperature is set between 23° and 95° F [-5° and +35° C] using a 0-10 volt potentiometer. Because this is a cooling application, if the temperature is above the setpoint value, the speed of the fan must be increased to provide more cooling air flow. The temperature sensor has a range of 14° to 104° F [-10° to +40° C] and uses a two-wire transmitter to provide a 4-20 mA signal. The output frequency range of the drive is 10 to 50 Hz.
1. Start/Stop via switch connected between terminals 12 (+24 V) and 18. 2. Temperature reference via a potentiometer (23°- 95° F [-5° to +35°
C], 0 10 V) connected to terminals 50 (+10 V), 53 (input) and 55 (common). 3. Temperature feedback via transmitter (14°-104° F [-10° – +40° C], 4-20 mA) connected to terminal 54. Switch S202 behind the local control panel set to ON (current input).

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2 Introduction to the VLT HVAC Drive

2.8.4 Programming Order

Function

Par. no.

Setting

  1. Make sure the motor runs properly. Do the following:

Set the drive to control the motor based on drive out- 0-02

Hz [1]

put frequency. Set the motor parameters using nameplate data.

1-2*

As specified by motor nameplate

2

Run Automatic Motor Adaptation.

1-29

Enable complete AMA [1] and then run the AMA

function.

  1. Make sure that the motor is running in the right direction.

Pressing [Hand On] starts the motor at 5 Hz in for-

If motor rotation direction is incorrect, two motor

ward direction, and the display shows: “Motor is run-

phase cables should be interchanged.

ning. Check if motor rotation direction is correct.

  1. Make sure the adjustable frequency drive limits are set to safe values.

Make sure that the ramp settings are within the ca- 3-41

60 sec.

pabilities of the drive and the allowed application 3-42

60 sec.

operating specifications.

Depends on motor/load size!

Also active in hand mode.

Prohibit the motor from reversing (if necessary)

4-10

Clockwise [0]

Set acceptable limits for the motor speed.

4-12

10 Hz

4-14

50 Hz

4-19

50 Hz

Switch from open-loop to closed-loop.

1-00

Closed-loop [3]

  1. Configure the feedback to the PID controller.

Set up Analog Input 54 as a feedback input.

20-00

Analog input 54 [2] (default)

Select the appropriate reference/feedback unit.

20-12

°C [60]

  1. Configure the setpoint reference for the PID controller.

Set acceptable limits for the setpoint reference.

3-02

23°F [-5°C]

3-03

95°F [35°C]

Set up Analog Input 53 as Reference 1 Source.

3-15

Analog input 53 [1] (default)

  1. Scale the analog inputs used for setpoint reference and feedback.

Scale Analog Input 53 for the temperature range of 6-10

0 V

the potentiometer (23°-95°F [-5°-+35°C], 0-10 V). 6-11

10 V (default)

6-14

23°F [-5°C]

6-15

95°F [35°C]

Scale Analog Input 54 for the temperature range of 6-22

4 mA

the temperature sensor (-14° – +104°F [-10° –

6-23

20 mA (default)

+40°C], 4-20 mA)

6-24

14°F [-10°C]

6-25

104°F [40°C]

  1. Tune the PID controller parameters.

Select inverse control, because the motor’s speed 20-81

Inverse [1]

should increase when the feedback is greater than

the setpoint reference.

Adjust the drive’s closed-loop controller, if needed. 20-93

See Optimization of the PID Controller below.

20-94

  1. Finished!

Save the parameter settings to the LCP for safekeep- 0-50

All to LCP [1]

ing.

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2 Introduction to the VLT HVAC Drive

VLT® HVAC Drive Design Guide

2.8.5 Tuning the Drive Closed-loop Controller

Once the drive’s closed-loop controller has been set up, the performance of the controller should be tested. In many cases, its performance may be

acceptable using the default values of PID Proportional Gain (par. 20-93) and PID Integral Time (par. 20-94). However, in some cases it may be helpful

to optimize these parameter values to provide faster system response while still controlling speed overshoot. In many situations, this can be done by

2

following the procedure below:

1. Start the motor.
2. Set par. 20-93 (PID Proportional Gain) to 0.3 and increase it until the feedback signal begins to oscillate. If necessary, start and stop the drive, or make step changes in the setpoint reference to attempt to cause oscillation. Next, reduce the PID Proportional Gain until the feedback signal stabilizes. Then reduce the proportional gain by 40-60%.
3. Set par. 20-94 (PID Integral Time) to 20 sec. and reduce it until the feedback signal begins to oscillate. If necessary, start and stop the drive, or make step changes in the setpoint reference to attempt to cause oscillation. Next, increase the PID Integral Time until the feedback signal stabilizes. Then increase the Integral Time by 15-50%.
4. Par. 20-95 (PID Differentiation Time) should only be used for very fast- acting systems. The typical value is 25% of the PID Integral Time (par. 20-94). The differentiator should only be used when the setting of the proportional gain and the integral time has been fully optimized. Make sure that oscillations of the feedback signal are sufficiently dampened by the low- pass filter for the feedback signal (par 6 16, 6 26, 5 54 or 5 59, as required).

2.8.6 Ziegler Nichols Tuning Method
In general, the above procedure is sufficient for HVAC applications. However, other, more sophisticated procedures can also be used. The Ziegler Nichols tuning method is a technique that was developed in the 1940s and is still commonly used today. It generally provides acceptable control performance using a simple experiment and parameter calculation.

NOTE! This method must not be used on applications that could be damaged by oscillations created by marginally stable control settings.

Figure 2.1: Marginally stable system
1. Select proportional control only. That is, PID Integral Time (par. 20-94) is set to Off (10,000 s), and the PID Differentiation Time (par. 20-95) is also set to Off (0 s in this case).
2. Increase the value of the PID Proportional Gain (par 20-93) until the point of instability is reached, as indicated by sustained oscillations of the feedback signal. The PID Proportional Gain that causes sustained oscillations is called the critical gain, Ku.
3. Measure the period of oscillation, Pu. NOTE: Pu should be measured when the amplitude of oscillation is relatively small. The output must not saturate (i.e., the maximum or minimum feedback signal must not be reached during the test).
4. Use the table below to calculate the necessary PID control parameters.

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VLT® HVAC Drive Design Guide

2 Introduction to the VLT HVAC Drive

Type of Control PI-control PID tight control PID some overshoot

Proportional Gain 0.45 Ku 0.6 Ku 0.33 * Ku

Integral Time 0.833 Pu 0.5 Pu 0.5 * Pu

Differentiation Time 0.125 Pu 0.33 Pu

Ziegler Nichols tuning for regulator, based on a stability boundary

2

Experience has shown that the control setting according to the Ziegler Nichols rule provides a good closed-loop response for many systems. If necessary,

the operator can perform the final tuning of the control iteratively in order to modify the response of the control loop.

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2 Introduction to the VLT HVAC Drive 2.8.7 Reference Handling
A block diagram of how the drive produces the remote reference is shown below.
2

VLT® HVAC Drive Design Guide

The Remote Reference is comprised of: · Preset references. · External references (analog inputs, pulse frequency inputs, digital potentiometer inputs and serial communication bus references).
· The preset relative reference. · Feedback controlled setpoint. Up to 8 preset references can be programmed in the drive. The active preset reference can be selected using digital inputs or the serial communications bus. The reference can also be supplied externally, most commonly from an analog input. This external source is selected by one of the 3 reference source parameters (par. 3-15, 3-16 and 3-17). Digipot is a digital potentiometer. This is also commonly called a speed up/slow control, or a floating point control. To set it up, one digital input is programmed to increase the reference, while another digital input is programmed to decrease the reference. A

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VLT® HVAC Drive Design Guide

2 Introduction to the VLT HVAC Drive

third digital input can be used to reset the digipot reference. All reference resources and the bus reference are added to produce the total external reference. The external reference, the preset reference or the sum of the two can be selected to be the active reference. Finally, this reference can be scaled by using the preset relative reference (par. 3-14).

The scaled reference is calculated as follows:

( ) Reference = X + X ×

Y 100

2

Where X is the external reference, the preset reference or the sum of these, and Y is the preset relative reference (par. 3-14) in [%].

NOTE! If Y, the preset relative reference (par. 3-14), is set to 0%, the reference will not be affected by the scaling

2.8.8 Feedback Handling
A block diagram of how the drive processes the feedback signal is shown below.

Feedback handling can be configured to work with applications requiring advanced control, such as multiple setpoints and multiple feedbacks. Three types of control are common.
Single Zone, Single Setpoint Single Zone, Single Setpoint is a basic configuration. Setpoint 1 is added to any other reference (if any, see Reference Handling), and the feedback signal is selected using par. 20-20.
Multi-zone, Single Setpoint Multi-zone, Single Setpoint uses two or three feedback sensors, but only one setpoint. The feedbacks can be added, subtracted (only feedback 1 and 2) or averaged. In addition, the maximum or minimum value may be used. Setpoint 1 is used exclusively in this configuration.

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2 Introduction to the VLT HVAC Drive

VLT® HVAC Drive Design Guide

Multi-zone, Multi-setpoint applies an individual setpoint reference to each feedback. The drive’s closed-loop controller chooses one pair to control the drive based on the user’s selection in par. 20-20. If Multi-setpoint Max [14] is selected, the setpoint/feedback pair with the smallest difference controls the drive’s speed. (Note that a negative value is always smaller than a positive value).

2

If Multi-setpoint Min [13] is selected, the setpoint/feedback pair with the largest difference controls the speed of the drive. Multi-setpoint Maximum [14]

attempts to keep all zones at or below their respective setpoints, while Multi-setpoint Min [13] attempts to keep all zones at or above their respective

setpoints.

Example: The setpoint of a two-zone, two-setpoint application, Zone 1, is 64° F [18° C], while the feedback is 66° F [19° C]. Zone 2 setpoint is 71° F [22° C] and the feedback is 68° F [20° C]. If Multi-setpoint Max [14] is selected, the setpoint and feedback of Zone 1 are sent to the PID controller, since this has the smaller difference (feedback is higher than setpoint, resulting in a negative difference). If Multi-setpoint Max [13] is selected, the setpoint and feedback of Zone 2 are sent to the PID controller, since this has the larger difference (feedback is lower than setpoint, resulting in a positive difference).

2.8.9 Feedback Conversion
In some applications, it may be useful to convert the feedback signal. One example of this is using a pressure signal to provide flow feedback. Since the square root of pressure is proportional to flow, the square root of the pressure signal yields a value proportional to the flow. This is shown below.

Another application that may benefit from feedback conversion is compressor control. In such applications, the output of a pressure sensor may be

converted to the refrigerant temperature using the equation:

Temperature

=

A2 (ln(pressure + 1) – A1)

– A3

where A1, A2 and A3 are refrigerant-specific constants.

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2 Introduction to the VLT HVAC Drive

2.9 General aspects of EMC

2.9.1 General Aspects of EMC Emissions

Electrical interference is usually conducted at frequencies in the range of 150 kHz to 30 MHz. Airborne interference from the drive system in the range

2

of 30 MHz to 1 GHz is generated from the inverter, motor cable and motor.

As shown in the illustration below, capacitive currents in the motor cable coupled with a high dV/dt from the motor voltage generate leakage currents.

The use of a shielded motor cable increases the leakage current (see illustration below), because shielded cables have higher capacitance to ground than

non-shielded cables. If the leakage current is not filtered, it will cause greater interference on the line power supply in the radio frequency range below

approximately 5 MHz. Because the leakage current (I1) is carried back to the unit through the shield (I 3), there will in principle only be a small electro-

magnetic field (I4) from the shielded motor cable according to the below figure.

The shield reduces the radiated interference, but increases the low-frequency interference in the line power supply. The motor cable shield must be connected to the adjustable frequency drive enclosure as well as on the motor enclosure. This is best done by using integrated shield clamps so as to avoid twisted shield ends (pigtails). These increase the shield impedance at higher frequencies, which reduces the shield effect and increases the leakage current (I4). If a shielded cable is used for the serial communication bus, relay, control cable, signal interface and brake, the shield must be mounted on the enclosure at both ends. In some situations, however, it will be necessary to break the shield to avoid current loops.

If the shield is to be placed on a mounting plate for the adjustable frequency drive, the mounting plate must be made of metal, because the shield currents have to be conveyed back to the unit. Moreover, ensure good electrical contact from the mounting plate through the mounting screws to the adjustable frequency driver chassis.
NOTE! When non-shielded cables are used, some emission requirements are not complied with, although the immunity requirements are observed.
In order to reduce the interference level from the entire system (unit + installation), make motor and brake cables as short as possible. Avoid placing cables with a sensitive signal level alongside motor and brake cables. Radio interference higher than 50 MHz (airborne) is especially generated by the control electronics.

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2 Introduction to the VLT HVAC Drive 2.9.2 EMC Test Results (Emission, Immunity)

VLT® HVAC Drive Design Guide

The following test results were obtained using a system with an adjustable frequency drive (with options, if rele-

vant), a shielded control cable, a control box with potentiometer, as well as a motor and motor-shielded cable.

2

RFI filter type

Conducted emission

Radiated emission

Industrial environment

Housing, Industrial envi- Housing, trades, and

trades, and

ronment

light industries

light industries

Set-up

EN 55011 EN 55011 EN 55011 EN 55011 Class EN 55011 Class B

Class A2

Class A1

Class B

A1

H1

1.4-60 hp [1.1-45 kW] 200-240 V

492 ft [150 m]

492 ft [150 m] 1)

164 ft [50 m]

Yes

No

1.5-125 hp [1.1-90 kW]

492 ft [150

380-480 V

492 ft [150 m]

m]

164 ft [50 m]

Yes

No

H2

1.5-5 hp [1.1-3.7 kW]

16 ft [5 m]

No

No

No

No

200-240 V

7.5-60 hp [5.5-45 kW]

200-240 V

82 ft [25 m]

No

No

No

No

1.5-10 hp [1.1-7.5 kW] 16 ft [5 m]

No

No

No

No

380-480 V

15-125 hp [11-90 kW]

380-480 V

82 ft [25 m]

No

No

No

No

150-600 hp [110-450 kW] 380-480

164 ft [50 m]

No

No

No

No

100-670 hp [75-500 kW] 525-600 V

492 ft [150 m]

No

No

No

No

H3

1.4-60 hp [1.1-45 kW]

200-240 V

75 m

50 m 1)

10 m

Yes

No

1.5-125 hp [1.1-90 kW] 380-480 V

75 m

164 ft [50 m]

10 m

Yes

No

H4

150-600 hp [110-450 kW] 380-480

492 ft [150 m]

45 m

No

Yes

No

100-450 hp [75-315 kW] 525-600 V

492 ft [150 m] 98 ft [30 m]

No

No

No

Hx

1.5-10 hp [1.1-7.5 kW]

525-600 V

Table 2.1: EMC Test Results (Emission, Immunity)

  1. 15 hp [11 kW] 200 V, H1 and H2 performance is delivered in enclosure type B1. 15 hp [11 kW] 200 V, H3 performance is delivered in enclosure type B2.

2.9.3 Required Compliance Levels

Standard / environment
IEC 61000-6-3 (generic) IEC 61000-6-4 EN 61800-3 (restricted) EN 61800-3 (unrestricted)

Housing, trades, and light industries

Conducted

Radiated

Class B

Class B

Class A1 Class B

Class A1 Class B

Industrial environment

Conducted

Radiated

Class A1 Class A1 Class A2

Class A1 Class A1 Class A2

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2 Introduction to the VLT HVAC Drive

EN 55011:

Threshold values and measuring methods for radio interference from industrial, scientific and

medical (ISM) high-frequency equipment.

Class A1:

Equipment used in a public supply network. Restricted distribution.

Class A2:

Equipment used in a public supply network.

Class B1:

Equipment used in areas with a public supply network (residential, commerce, and light industries).

Unrestricted distribution.

2

2.9.4 EMC Immunity
In order to document immunity against interference from electrical phenomena, the following immunity tests have been performed on a system consisting of an adjustable frequency drive (with options, if relevant), a shielded control cable and a control box with potentiometer, motor cable and motor.
The tests were performed in accordance with the following basic standards:
· EN 61000-4-2 (IEC 61000-4-2): Electrostatic discharges (ESD): Simulation of electrostatic discharges from human beings. · EN 61000-4-3 (IEC 61000-4-3): Incoming electromagnetic field radiation, amplitude modulated Simulation of the effects of radar and radio
communication equipment, as well as mobile communications. · EN 61000-4-4 (IEC 61000-4-4): Electrical interference: Simulation of interference brought about by switching with a contactor, relays or
similar devices. · EN 61000-4-5 (IEC 61000-4-5): Surge transients: Simulation of transients brought about by lightning that strikes near installations (e.g.). · EN 61000-4-6 (IEC 61000-4-6): RF Common mode: Simulation of the effect from radio-transmitting equipment connected to cables. See following EMC immunity form.

VLT HVAC; 200-240 V, 380-480 V Basic standard
Acceptance criterion Line
Motor Brake Load sharing Control wires Standard bus Relay wires Application and serial communication options LCP cable External 24 V DC
Enclosure
AD: Air Discharge CD: Contact Discharge CM: Common mode DM: Differential mode

  1. Injection on cable shield
    Table 2.2: Immunity

Burst IEC 61000-4-4
B
4 kV CM
4 kV CM 4 kV CM 4 kV CM 2 kV CM 2 kV CM 2 kV CM 2 kV CM
2 kV CM
2 kV CM

Surge IEC 61000-4-5
B 2 kV/2 DM 4 kV/12 CM
4 kV/2 1) 4 kV/2 1) 4 kV/2 1)
2 kV/2 1) 2 kV/2 1) 2 kV/2 1)
2 kV/2 1)
2 kV/2 1) 0.5 kV/2 DM 1 kV/12 CM

ESD IEC 61000-4-2
B

— — — — — —



8 kV AD 6 kV CD

Radiated electromagnetic field IEC 61000-4-3
A

— — — — — —



10 V/m

RF common mode voltage IEC 61000-4-6
A
10 VRMS
10 VRMS 10 VRMS 10 VRMS 10 VRMS 10 VRMS 10 VRMS
10 VRMS
10 VRMS
10 VRMS

2.10 Galvanic isolation (PELV)
PELV offers protection by way of extra low voltage. Protection against electric shock is ensured when the electrical supply is of the PELV type and the installation is made as described in local/national regulations on PELV supplies.

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2 Introduction to the VLT HVAC Drive

VLT® HVAC Drive Design Guide

All control terminals and relay terminals 01-03/04-06 comply with PELV (Protective Extra Low Voltage – does not apply to 525-600 V units and at grounded Delta leg above 300 V).
Galvanic (ensured) isolation is obtained by fulfilling requirements for higher isolation and by providing the relevant creepage/clearance distances. These requirements are described in the EN 61800-5-1 standard.
2 The components that make up the electrical isolation, as described below, also comply with the requirements for higher isolation and the relevant test as described in EN 61800-5-1. The PELV galvanic isolation can be shown in six locations (see illustration):
In order to maintain PELV, all connections made to the control terminals must be PELV. For example, the thermistor must be reinforced/double insulated.
1. Power supply (SMPS) incl. signal isolation of UDC, indicating the intermediate current voltage. 2. Gate drive that runs the IGBTs (trigger transformers/opto-couplers). 3. Current transducers. 4. Opto-coupler, brake module. 5. Internal soft-charge, RFI and temperature measurement circuits. 6. Custom relays.

Figure 2.2: Galvanic isolation
The functional galvanic isolation (a and b in drawing) is for the 24 V backup option and for the RS-485 standard bus interface.
At altitudes higher than 6,600 feet [2 km], please contact Danfoss Drives regarding PELV.
2.11 Ground leakage current
Warning: Touching the electrical parts may be fatal – even after the equipment has been disconnected from line power. Make sure that other voltage inputs have been disconnected, such as load-sharing (linkage of DC intermediate circuit), as well as the motor connection for kinetic back-up. Before touching any electrical parts, wait at least: Please consult the section Safety>Caution. Shorter time than stated in the table is allowed only if indicated on the nameplate for the specific unit.

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2 Introduction to the VLT HVAC Drive

Leakage Current

The ground leakage current from the adjustable frequency drive exceeds 3.5 mA. To ensure that the ground cable has a good me-

chanical connection to the ground connection (terminal 95), the cable cross- section must be at least 0.016 in.2 [10 mm2] or have 2

rated ground wires terminated separately.

Residual Current Device

This product can cause DC current in the protective conductor. Where a residual current device (RCD) is used for extra protection, only

2

an RCD of Type B (time delayed) shall be used on the supply side of this product. See also RCD Application Note MN.90.Gx.yy.

Protective grounding of the adjustable frequency drive and the use of RCDs must always follow national and local regulations.

2.12 Control with brake function
2.12.1 Selection of Brake Resistor
In certain applications, such as in tunnels or underground railway station ventilation systems, it is desirable to bring the motor to a stop more rapidly than can be achieved through controlling via ramp-down or free-wheeling. In such applications, dynamic braking with a braking resistor may be utilized. Using a braking resistor ensures that the energy is absorbed in the resistor and not in the adjustable frequency drive.
If the amount of kinetic energy transferred to the resistor in each braking period is not known, the average power can be calculated on the basis of the cycle time and braking time, also known as the intermitted duty cycle. The resistor intermittent duty cycle is an indication of the duty cycle at which the resistor is active. The figure below shows a typical braking cycle.
The intermittent duty cycle for the resistor is calculated as follows:
Duty Cycle = tb / T
T = cycle time in seconds tb is the braking time in seconds (as part of the total cycle time)

Danfoss offers brake resistors with duty cycle of 5%, 10% and 40% suitable for use with the VLT® FC102 HVAC drive series. If a 10% duty cycle resistor is applied, it is capable of absorbing braking energy up to 10% of the cycle time, with the remaining 90% being used to dissipate heat from the resistor.
For further selection advice, please contact Danfoss.

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2 Introduction to the VLT HVAC Drive

VLT® HVAC Drive Design Guide

NOTE! If a short circuit in the brake transistor occurs, power dissipation in the brake resistor is only prevented by using a line switch or contactor to disconnect the AC line for the adjustable frequency drive. (The contactor can be controlled by the adjustable frequency drive).
2
2.12.2 Brake Resistor Calculation

The brake resistance is calculated as shown:

Rbr

=

U d2c Ppeak

where

Ppeak = Pmotor x Mbr x motor x VLT[W]

As can be seen, the brake resistance depends on the intermediate circuit voltage (UDC). The brake function of the adjustable frequency drive is settled in 3 areas of the line power supply:

Size 3 x 200-240 V 3 x 380-480 V 3 x 525-600 V

Brake active 390 V (UDC) 778 V 943 V

Warning before cut out Cut out (trip)

405 V

410 V

810 V

820 V

965 V

975 V

NOTE! Make sure that the brake resistor can cope with a voltage of 410 V, 820 V or 975 V – unless Danfoss brake resistors are used.

Danfoss recommends the brake resistance Rrec, i.e., one that guarantees that the adjustable frequency drive is able to brake at the highest braking torque (Mbr(%)) of 110%. The formula can be written as:

Rrec

=

U

2 dc

x

100

Pmotor x Mbr (%) x VLT x motor

motor is typically at 0.90

VLT is typically at 0.98

For 200 V, 480 V and 600 V adjustable frequency drives, Rrec at 160% braking torque is written as:

200V

:

Rrec

=

107780 Pmotor

480V

: Rrec =

375300 Pmotor

600V

: Rrec =

630137 Pmotor

  1. For adjustable frequency drives 10 hp [7.5 kW) shaft output

  2. For adjustable frequency drives > 10 hp [7.5 kW] shaft output

480V

: Rrec =

428914 Pmotor

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VLT® HVAC Drive Design Guide

2 Introduction to the VLT HVAC Drive

NOTE! The resistor brake circuit resistance selected should not be higher than that recommended by Danfoss. If a brake resistor with a higher ohmic value is selected, the braking torque may not be achieved because there is a risk that the adjustable frequency drive cuts out for safety reasons.

NOTE!

2

If a short circuit in the brake transistor occurs, power dissipation in the brake resistor is only prevented by using a line switch or

contactor to disconnect the AC line for the adjustable frequency drive. (The contactor can be controlled by the adjustable frequency

drive).

NOTE! Do not touch the brake resistor, as it can get very hot during/after braking.

2.12.3 Control with Brake Function
The brake is to limit the voltage in the intermediate circuit when the motor acts as a generator. This occurs, for example, when the load drives the motor and the power accumulates on the DC link. The brake is built up as a chopper circuit with the connection of an external brake resistor.
Placing the brake resistor externally offers the following advantages: – The brake resistor can be selected on the basis of the application in question. – The braking energy can be dissipated outside the control panel, i.e., where the energy can be utilized. – The electronics of the adjustable frequency drive will not overheat if the brake resistor is overloaded.
The brake is protected against short-circuiting of the brake resistor, and the brake transistor is monitored to ensure that short-circuiting of the transistor is detected. A relay/digital output can be used for protecting the brake resistor against overloading in connection with a fault in the adjustable frequency drive. In addition, the brake makes it possible to read out the momentary power and the mean power for the last 120 seconds. The brake can also monitor the power energizing and ensure that it does not exceed a limit set in par. 2-12. In par. 2-13, select the function to carry out when the power transmitted to the brake resistor exceeds the limit set in par. 2-12.
NOTE! Monitoring the braking energy is not a safety function; a thermal switch is required for that purpose. The brake resistor circuit is not protected against ground leakage.
Overvoltage control (OVC) (exclusive brake resistor) can be selected as an alternative brake function in par. 2-17. This function is active for all units. The function ensures that a trip can be avoided if the DC link voltage increases. This is done by increasing the output frequency to limit the voltage from the DC link. It is a very useful function if, for example, the ramp-down time is too short because tripping the adjustable frequency drive is avoided. In this situation, the ramp-down time is extended.
2.13 Mechanical brake control
2.13.1 Brake Resistor Cabling
EMC (twisted cables/shielding) To reduce the electrical noise from the wires between the brake resistor and the adjustable frequency drive, the wires must be twisted.

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2 Introduction to the VLT HVAC Drive

VLT® HVAC Drive Design Guide

For enhanced EMC performance, a metal shield can be used.

2.14 Extreme running conditions

Short Circuit (Motor Phase ­ Phase)

2

The adjustable frequency drive is protected against short circuits by means of current measurement in each of the three motor phases or in the DC link.

A short circuit between two output phases will cause an overcurrent in the inverter. The inverter will be turned off individually when the short circuit

current exceeds the permitted value (Alarm 16 Trip Lock).

To protect the drive against a short circuit at the load sharing and brake outputs, please see the design guidelines.

Switching on the Output Switching on the output between the motor and the adjustable frequency drive is fully permitted. You cannot damage the adjustable frequency drive in any way by switching on the output. However, fault messages may appear.

Motor-generated Overvoltage The voltage in the intermediate circuit is increased when the motor acts as a generator. This occurs in the following cases:

1. The load drives the motor (at constant output frequency from the adjustable frequency drive), i.e., the load generates energy.
2. During deceleration (“ramp-down”), if the moment of inertia is high the friction is low and the ramp-down time is too short for the energy to be dissipated as a loss in the adjustable frequency drive, the motor and the installation.
3. Incorrect slip compensation setting may cause higher DC link voltage. The control unit may attempt to correct the ramp if possible (par. 2-17 Overvoltage Control. The inverter turns off to protect the transistors and the intermediate circuit capacitors when a certain voltage level is reached. See par. 2-10 and par. 2-17 to select the method used for controlling the intermediate circuit voltage level.

Line Drop-out During a line drop-out, the adjustable frequency drive keeps running until the intermediate circuit voltage drops below the minimum stop level, which is typically 15% below the adjustable frequency drive’s lowest rated supply voltage.

The line voltage before the drop-out and the motor load determine how long it takes for the inverter to coast.

Static Overload in VVCplus mode When the adjustable frequency drive is overloaded (the torque limit in par. 4-16/4-17 is reached), the control reduces the output frequency to reduce the load. If the overload is excessive, a current may occur that makes the adjustable frequency drive cut out after approximately 5-10 s.

Operation within the torque limit is limited in time (0-60 s) in par. 14-25.

2.14.1 Motor Thermal Protection
The motor temperature is calculated on the basis of motor current, output frequency, and time or thermistor. See par. 1-90 in the Programming Guide.

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2 Introduction to the VLT HVAC Drive
2

2.15 Safe Stop
2.15.1 Safe Stop
The adjustable frequency drive can perform the safety function Safe Torque Off (As defined by draft CD IEC 61800-5-2) or Stop Category 0 (as defined in EN 60204-1). It is designed and deemed suitable for the requirements of Safety Category 3 in EN 954-1. This function is called safe stop. Prior to integrating and using safe stop in an installation, a thorough risk analysis must be carried out on the installation in order to determine whether the safe stop functionality and safety category are appropriate and sufficient. In order to install and use the safe stop function in accordance with the requirements of Safety Category 3 in EN 954-1, the related information and instructions in the relevant Design Guide must be followed! The information and instructions contained in the Instruction Manual are not sufficient for a correct and safe use of the safe stop functionality!

MG.11.B5.22 – VLT® is a registered Danfoss trademark.

2-39

2 Introduction to the VLT HVAC Drive
2

VLT® HVAC Drive Design Guide

Figure 2.3: Diagram showing all electrical terminals. (Terminal 37 present for units with safe stop function only.)
2.15.2 Safe Stop Installation
To carry out an installation of a Category 0 Stop (EN60204) in conformity with Safety Category 3 (EN954-1), follow these instructions: 1. The bridge (jumper) between Terminal 37 and 24 V DC must be removed. Cutting or breaking the jumper is not sufficient. Remove it entirely to avoid short-circuiting. See jumper on illustration. 2. Connect terminal 37 to 24 V DC by a short circuit- protected cable. The 24 V DC voltage supply must be interruptible by an EN954-1 category 3 circuit interrupt device. If the interrupt device and the adjustable frequency drive are placed in the same installation panel, you can use an unshielded cable instead of a shielded one.

2-40

MG.11.B5.22 – VLT® is a registered Danfoss trademark.

VLT® HVAC Drive Design Guide

2 Introduction to the VLT HVAC Drive
2

Figure 2.4: Bridge jumper between terminal 37 and 24 VDC
The illustration below shows a Stopping Category 0 (EN 60204-1) with safety Category 3 (EN 954-1). The circuit interruption is caused by an opening door contact. The illustration also shows how to connect a non-safety-related hardware coast.

Figure 2.5: Illustration of the essential aspects of an installation to achieve a Stopping Category 0 (EN 60204-1) with safety Category 3 (EN 954-1).

MG.11.B5.22 – VLT® is a registered Danfoss trademark.

2-41

2 Introduction to the VLT HVAC Drive
2

VLT® HVAC Drive Design Guide

2-42

MG.11.B5.22 – VLT® is a registered Danfoss trademark.

VLT® HVAC Drive Design Guide
3 VLT HVAC Selection

VLT HVAC Selection

3.1 Specifications
3.1.1 Line Supply 3 x 200-240 V AC

Normal overload 110% for 1 minute IP 20

A2

A2

A2

A3

A3

3

IP 21

A2

A2

A2

A3

A3

IP 55

A5

A5

A5

A5

A5

IP 66

A5

A5

A5

A5

A5

Line supply 200-240 V AC

Adjustable frequency drive

P1K1 P1K5 P2K2 P3K0 P3K7

Typical Shaft Output [kW]

1.1 1.5 2.2

3

3.7

Typical Shaft Output [HP] at 208 V

1.5 2.0 2.9 4.0 4.9

Output current

Continuous (3 x 200-240 V) [A]

6.6 7.5 10.6 12.5 16.7

Intermittent (3 x 200-240 V) [A]

7.3 8.3 11.7 13.8 18.4

Continuous kVA (208 V AC) [kVA]

2.38 2.70 3.82 4.50 6.00

Max. cable size:

(line, motor, brake) [mm2 /AWG] 2)

4/10

Max. input current

Continuous (3 x 200-240 V) [A]

5.9 6.8 9.5 11.3 15.0

Intermittent (3 x 200-240 V) [A]

6.5 7.5 10.5 12.4 16.5

Max. pre-fuses1) [A]

20

20

20

32

32

Environment

Estimated power loss at rated max. load [W] 4)

63

82 116 155 185

Weight enclosure IP 20 [kg]

4.9 4.9 4.9 6.6 6.6

Weight enclosure IP 21 [kg]

5.5 5.5 5.5 7.5 7.5

Weight enclosure IP 55 [kg] 13.5 13.5 13.5 13.5 13.5

Weight enclosure IP 66 [kg]

13.5 13.5 13.5 13.5 13.5

Efficiency 3)

0.96 0.96 0.96 0.96 0.96

MG.11.B5.22 – VLT® is a registered Danfoss trademark.

3-1

3 VLT HVAC Selection

VLT® HVAC Drive Design Guide

Normal overload 110% for 1 minute

IP 21

B1

B1

B1

B2

IP 55

B1

B1

B1

B2

IP 66

B1

B1

B1

B2

Line supply 200-240 V AC

Adjustable frequency drive

P5K5 P7K5 P11K

P15K

Typical Shaft Output [kW]

5.5

7.5

11

15

Typical Shaft Output [HP] at 208 V

7.5

10

15

20

Output current

3

Continuous (3 x 200-240 V) [A]

24.2 30.8

46.2

59.4

Intermittent (3 x 200-240 V) [A]

26.6 33.9

50.8

65.3

Continuous kVA (208 V AC) [kVA]

8.7

11.1

16.6

21.4

Max. cable size:

(line, motor, brake) [mm2 /AWG] 2)

10/7

35/2

Max. input current

Continuous (3 x 200-240 V) [A]

22.0 28.0

42.0

54.0

Intermittent (3 x 200-240 V) [A]

24.2 30.8

46.2

59.4

Max. pre-fuses1) [A]

63

63

63

80

Environment

Estimated power loss at rated max. load [W] 4)

269

310

447

602

Weight enclosure IP 20 [kg]

Weight enclosure IP 21 [kg]

23

23

23

27

Weight enclosure IP 55 [kg]

23

23

23

27

Weight enclosure IP 66 [kg]

23

23

23

27

Efficiency 3)

0.96 0.96

0.96

0.96

3-2

MG.11.B5.22 – VLT® is a registered Danfoss trademark.

VLT® HVAC Drive Design Guide

3 VLT HVAC Selection

Normal overload 110% for 1 minute IP 20 IP 21

C1

C1

C1

C2

C2

IP 55

C1

C1

C1

C2

C2

IP 66

C1

C1

C1

C2

C2

Line supply 200-240 V AC

Adjustable frequency drive

P18K P22K P30K P37K P45K

Typical Shaft Output [kW]

18.5 22

30

37

45

Typical Shaft Output [HP] at 208 V Output current

25

30

40

50

60

3

Continuous (3 x 200-240 V) [A]

74.8 88.0 115 143

170

Intermittent (3 x 200-240 V) [A]

82.3 96.8 127 157

187

Continuous kVA (208 V AC) [kVA]

26.9 31.7 41.4 51.5 61.2

Max. cable size:

(line, motor, brake) [mm2 /AWG] 2)

50/1/0

95/4/0 120/250 MCM

Max. input current

Continuous (3 x 200-240 V) [A]

68.0 80.0 104.0 130.0 154.0

Intermittent (3 x 200-240 V) [A]

74.8 88.0 114.0 143.0 169.0

Max. pre-fuses1) [A]

125 125 160 200

250

Environment

Estimated power loss at rated max. load [W] 4)

737 845 1140 1353 1636

Weight enclosure IP 20 [kg]

Weight enclosure IP 21 [kg]

45

45

65

65

65

Weight enclosure IP 55 [kg]

45

45

65

65

65

Weight enclosure IP 66 [kg]

45

45

65

65

65

Efficiency 3)

0.96 0.97 0.97 0.97 0.97

MG.11.B5.22 – VLT® is a registered Danfoss trademark.

3-3

3 VLT HVAC Selection

3.1.2 Line Supply 3 x 380-480 V AC

Normal overload 110% for 1 minute

Adjustable frequency drive

Typical Shaft Output [kW]

Typical Shaft Output [HP] at 460 V

IP 20

IP 21

IP 55

3

IP 66

Output current

Continuous

(3 x 380-440 V) [A]

Intermittent

(3 x 380-440 V) [A]

Continuous

(3 x 440-480 V) [A]

Intermittent

(3 x 440-480 V) [A]

Continuous kVA

(400 V AC) [kVA]

Continuous kVA

(460 V AC) [kVA]

Max. cable size:

(line, motor, brake)

[[mm2/

AWG] 2)

Max. input current

Continuous

(3 x 380-440 V) [A]

Intermittent

(3 x 380-440 V) [A]

Continuous

(3 x 440-480 V) [A]

Intermittent

(3 x 440-480 V) [A]

Max. pre-fuses1)[A]

Environment

Estimated power loss

at rated max. load [W] 4)

Weight enclosure IP 20 [kg]

Weight enclosure IP 21 [kg]

Weight enclosure IP 55 [kg]

Weight enclosure IP 66 [kg]

Efficiency 3)

VLT® HVAC Drive Design Guide

P1K1 1.1 1.5 A2
A5 A5

P1K5 1.5 2.0 A2
A5 A5

P2K2 2.2 2.9 A2
A5 A5

P3K0 3 4.0 A2
A5 A5

P4K0 4 5.3 A2
A5 A5

P5K5 5.5 7.5 A3
A5 A5

P7K5 7.5 10 A3
A5 A5

3

4.1

5.6

7.2

10

13

16

3.3

4.5

6.2

7.9

11

14.3 17.6

2.7

3.4

4.8

6.3

8.2

11

14.5

3.0

3.7

5.3

6.9

9.0 12.1 15.4

2.1

2.8

3.9

5.0

6.9

9.0 11.0

2.4

2.7

3.8

5.0

6.5

8.8 11.6

4/ 10

2.7

3.7

5.0

6.5

9.0

11.7 14.4

3.0

4.1

5.5

7.2

9.9

12.9 15.8

2.7

3.1

4.3

5.7

7.4

9.9

13.0

3.0

3.4

4.7

6.3

8.1

10.9 14.3

10

10

20

20

20

32

32

58

62

88

116

124

187 255

4.8

4.9

4.9

4.9

4.9

6.6

6.6

13.5 13.5 13.5 13.5 13.5 14.2 14.2 13.5 13.5 13.5 13.5 13.5 14.2 14.2 0.96 0.97 0.97 0.97 0.97 0.97 0.97

3-4

MG.11.B5.22 – VLT® is a registered Danfoss trademark.

VLT® HVAC Drive Design Guide

3 VLT HVAC Selection

Normal overload 110% for 1 minute Adjustable frequency drive Typical Shaft Output [kW] Typical Shaft Output [HP] at 460 V IP 20 IP 21

P11K 11 15

P15K 15 20

P18K 18.5 25

P22K 22 30

P30K 30 40

P37K 37 50

P45K 45 60

P55K 55 75

P75K 75 100

P90K 90 125

B1 B1 B1 B2 B2

C1 C1 C1 C2

C2

IP 55 IP 66 Output current
Continuous (3 x 380-440 V) [A] Intermittent (3 x 380-440 V) [A] Continuous (3 x 440-480 V) [A] Intermittent (3 x 440-480 V) [A] Continuous kVA (400 V AC) [kVA] Continuous kVA (460 V AC) [kVA] Max. cable size: (line, motor, brake) [[mm2/ AWG] 2) Max. input current

B1 B1 B1 B2 B2 C1 C1 C1 C2

B1 B1 B1 B2 B2 C1 C1 C1 C2

3

24 32 37.5 44 61 73 90 106 147 177

26.4 35.2 41.3 48.4 67.1 80.3 99 117 162 195

21 27 34 40 52 65 80 105 130 160

23.1 29.7 37.4 44 61.6 71.5 88 116 143 176

16.6 22.2 26 30.5 42.3 50.6 62.4 73.4 102 123

16.7 21.5 27.1 31.9 41.4 51.8 63.7 83.7 104 128

10/7

35/2

50/1/0

104 128

Continuous (3 x 380-440 V) [A]

22 29 34 40 55 66 82 96 133 161

Intermittent (3 x 380-440 V) [A]

24.2 31.9 37.4 44 60.5 72.6 90.2 106 146 177

Continuous (3 x 440-480 V) [A]

19 25 31 36 47 59 73 95 118 145

Intermittent (3 x 440-480 V) [A]

20.9 27.5 34.1 39.6 51.7 64.9 80.3 105 130 160

Max. pre-fuses1)[A]

63 63 63 63 80 100 125 160 250 250

Environment

Estimated power loss at rated max. load [W] 4)

278 392 465 525 739 698 843 1083 1384 1474

Weight enclosure IP 20 [kg]

Weight enclosure IP 21 [kg] 23 23 23 27 27 45 45 45 65

65

Weight enclosure IP 55 [kg] 23 23 23 27 27 45 45 45 65

65

Weight enclosure IP 66 [kg] 23 23 23 27 27 45 45 45

Efficiency 3)

0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.99

MG.11.B5.22 – VLT® is a registered Danfoss trademark.

3-5

3 VLT HVAC Selection
3

Normal overload 110% for 1 minute

3-6

Adjustable frequency drive

P110

P132

P160

P200

P250

P315

P355

P400

P450

Typical Shaft Output [kW]

110

132

160

200

250

315

355

400

450

Typical Shaft Output [HP] at 460V

150

200

250

300

350

450

500

550

600

IP 00

D3

D3

D4

D4

D4

E2

E2

E2

E2

IP 21

D1

D1

D2

D2

D2

E1

E1

E1

E1

IP 54

D1

D1

D2

D2

D2

E1

E1

E1

E1

Output current

Continuous (3 x 400 V) [A]

212

260

315

395

480

600

658

745

800

Intermittent (3 x 400 V) [A]

233

286

347

435

528

660

724

820

880

Continuous (3 x 460-500 V) [A]

190

240

302

361

443

540

590

678

730

Intermittent (3 x 460-500 V) [A]

209

264

332

397

487

594

649

746

803

Continuous kVA (400 V AC) [kVA]

147

180

218

274

333

416

456

516

554

Continuous kVA (460 V AC) [kVA]

151

191

241

288

353

430

470

540

582

Max. cable size:

(line power, motor, brake) [mm2/ AWG] 2)

2×70 2×2/0

2×185 2×350 mcm

4×240 4×500 mcm

Max. input current

Continuous (3 x 400 V) [A]

204

251

304

381

463

590

647

733

787

Continuous (3 x 460/500V) [A]

183

231

291

348

427

531

580

667

718

Max. pre-fuses1)[A]

300

350

400

500

600

700

900

900

900

MG.11.B5.22 – VLT® is a registered Danfoss trademark.

Environment

Estimated power loss at rated max. load [W] 4)

3234

3782

4213

5119

5893

7630

7701

8879

9428

Weight enclosure IP 00 [kg]

81.9

90.5

111.8

122.9

137.7

221.4

234.1

236.4

277.3

Weight enclosure IP 21 [kg]

95.5

104.1

125.4

136.3

151.3

263.2

270.0

272.3

313.2

Weight enclosure IP 54 [kg]

95.5

104.1

125.4

136.3

151.3

263.2

270.0

272.3

313.2

Efficiency 3)

0.98

0.98

0.98

0.98

0.98

0.98

0.98

0.98

0.98

  1. For type of fuse, see section Fuses.

  2. American Wire Gauge

  3. Measured using 16.4 ft. [5 m] shielded motor cables at rated load and rated frequency.

  4. The typical power loss is at normal load conditions and expected to be within +/- 15% (tolerance relates to variety in voltage and cable conditions).

Values are based on a typical motor efficiency (eff2/eff3 border line). Lower efficiency motors will also add to the power loss in the adjustable frequency drive and vice versa.

If the switching frequency is raised from nominal, the power losses may rise significantly.

LCP and typical control card power consumption values are included. Further options and customer load may add up to 30 W to the losses. (though typically only 4W extra for a fully loaded control card, or options

for slot A or slot B, each).

Although measurements are made with state of the art equipment, some measurement inaccuracy must be allowed for (+/- 5%).

VLT® HVAC Drive Design Guide

VLT® HVAC Drive Design Guide

3 VLT HVAC Selection

3.1.3 Line Supply 3 x 525-600 V AC

Normal overload 110% for 1 minute

Size:

P1K1 P1K5 P2K2 P3K0 P3K7 P4K0 P5K5 P7K5

Typical Shaft Output [kW]

1.1

1.5

2.2

3

3.7

4

5.5

7.5

Output current

Continuous (3 x 525-550 V) [A] Intermittent (3 x 525-550 V) [A]

2.6

2.9

4.1

5.2

6.4

9.5

11.5

3

2.9

3.2

4.5

5.7

7.0

10.5 12.7

Continuous (3 x 525-600 V) [A]

2.4

2.7

3.9

4.9

6.1

9.0

11.0

Intermittent (3 x 525-600 V) [A]

2.6

3.0

4.3

5.4

6.7

9.9

12.1

Continuous kVA (525 V AC) [kVA]

2.5

2.8

3.9

5.0

6.1

9.0

11.0

Continuous kVA (575 V AC) [kVA]

2.4

2.7

3.9

4.9

6.1

9.0

11.0

Max. cable size

24 – 10 AWG

(line, motor, brake)

– 0.00031-0.0062 in. [0.2-4

[AWG] 2) [mm2]

mm]2

Max. input current

Continuous (3 x 525-600 V) [A]

2.4

2.7

4.1

5.2

5.8

8.6

10.4

Intermittent (3 x 525-600 V) [A]

2.7

3.0

4.5

5.7

6.4

9.5

11.5

Max. pre-fuses1) [A]

10

10

20

20

20

32

32

Environment

Estimated power loss at rated max. load [W] 4)

50

65

92

122

145

195

261

Enclosure IP 20

Weight, enclosure IP 20 [kg]

6.5

6.5

6.5

6.5

6.5

6.6

6.6

Efficiency 4)

0.97 0.97 0.97 0.97 – 0.97 0.97 0.97

MG.11.B5.22 – VLT® is a registered Danfoss trademark.

3-7

3 VLT HVAC Selection
3

Normal overload 110% for 1 minute

3-8

Adjustable frequency drive

P110

P132

P160

P200

P250

P315

P355

P400

P500

P560

Typical Shaft Output [kW]

110

132

160

200

250

315

355

400

500

560

Typical Shaft Output [HP] at 575 V

150

200

250

300

350

400

450

500

600

650

IP 00

D3

D3

D4

D4

D4

D4

E2

E2

E2

E2

IP 21

D1

D1

D2

D2

D2

D2

E1

E1

E1

E1

IP 54

D1

D1

D2

D2

D2

D2

E1

E1

E1

E1

Output current

Continuous (3 x 550 V) [A]

162

201

253

303

360

418

470

523

596

630

Intermittent (3 x 550 V) [A]

178

221

278

333

396

460

517

575

656

693

Continuous (3 x 575-690V) [A]

155

192

242

290

344

400

450

500

570

630

Intermittent (3 x 575-690 V) [A]

171

211

266

319

378

440

495

550

627

693

Continuous kVA (550 V AC) [kVA]

154

191

241

289

343

398

448

498

568

600

Continuous kVA (575 V AC) [kVA]

154

191

241

289

343

398

448

498

568

627

Continuous kVA (690 V AC) [kVA]

185

229

289

347

411

478

538

598

681

753

Max. cable size:

(line power, motor, brake) [mm2/ AWG] 2)

2×70 2×2/0

2×185 2×350 mcm

4×240 4×500 mcm

Max. input current

Continuous (3 x 550 V) [A]

158

198

245

299

355

408

453

504

574

607

Continuous (3 x 575 V) [A]

151

189

234

286

339

390

434

482

549

607

MG.11.B5.22 – VLT® is a registered Danfoss trademark.

Continuous (3 x 690 V) [A]

155

197

240

296

352

400

434

482

549

607

Max. pre-fuses1)[A]

225

250

350

400

500

600

700

700

900

900

Environment

Estimated power loss at rated max. load [W] 4)

3114

3612

4293

5156

5821

6149

6449

7249

8727

9673

Weight enclosure IP 00 [kg]

81.9

90.5

111.8

122.9

137.7

151.3

221

221

236

277

Weight enclosure IP 21 [kg]

95.5

104.1

125.4

136.3

151.3

164.9

263

263

272

313

Weight enclosure IP 54 [kg]

95.5

104.1

125.4

136.3

151.3

164.9

263

263

272

313

Efficiency 3)

0.98

0.98

0.98

0.98

0.98

0.98

0.98

0.98

0.98

0.98

  1. For type of fuse, see section Fuses.

  2. American Wire Gauge

  3. Measured using 16.4 ft. [5 m] shielded motor cables at rated load and rated frequency.

  4. The typical power loss is at normal load conditions and expected to be within +/- 15% (tolerance relates to variety in voltage and cable conditions).

Values are based on a typical motor efficiency (eff2/eff3 border line). Lower efficiency motors will also add to the power loss in the adjustable frequency drive and vice versa.

If the switching frequency is raised from nominal, the power losses may rise significantly.

LCP and typical control card power consumption values are included. Further options and customer load may add up to 30 W to the losses. (though typically only 4W extra for a fully loaded control card, or options

for slot A or slot B, each).

Although measurements are made with state of the art equipment, some measurement inaccuracy must be allowed for (+/- 5%).

VLT® HVAC Drive Design Guide

VLT® HVAC Drive Design Guide

3 VLT HVAC Selection

Line power supply (L1, L2, L3): Supply voltage Supply voltage Supply frequency Max. imbalance temporary between line phases True Power Factor () Displacement Power Factor (cos) near unity Switching on input supply L1, L2, L3 (power-ups) enclosure type A Switching on input supply L1, L2, L3 (power-ups) enclosure type B, C Switching on input supply L1, L2, L3 (power-ups) enclosure type D, E Environment according to EN60664-1

380-480 V ±10%

525-600 V ±10%

50/60 Hz

3.0% of rated supply voltage

0.9 nominal at rated load

(> 0.98)

maximum twice/min.

maximum once/min.

3

maximum once/2 min.

overvoltage category III / pollution degree 2

The unit is suitable for use on a circuit capable of delivering not more than 100.000 RMS symmetrical Amperes, 480/600 V maximum.

Motor output (U, V, W): Output voltage Output frequency Switching on output Ramp times Torque characteristics: Starting torque (Constant torque) Starting torque Overload torque (Constant torque)

0 – 100% of supply voltage 0 – 1000 Hz Unlimited
1 – 3600 sec.
maximum 110% for 1 min. maximum 120% up to 0.5 sec.
maximum 110% for 1 min.*

*Percentage relates to the nominal torque for the VLT HVAC Drive.

Cable lengths and cross-sections: Max. motor cable length, shielded/armored Max. motor cable length, unshielded/unarmored Max. cross-section to motor, line power, load sharing and brake * Maximum cross-section to control terminals, rigid wire Maximum cross-section to control terminals, flexible cable Maximum cross-section to control terminals, cable with enclosed core Minimum cross-section to control terminals

VLT HVAC Drive: 492 ft [150 m] VLT HVAC Drive: 984 ft [300 m] 0.0023 in.2 [1.5 mm2]/16 AWG (2 x 0.0012 in.2 [2 x 0.75 mm2]) 0.0016 in.2 [1 mm2]/18 AWG
0.00078 in.2 [0.5 mm2]/20 AWG 0.00039 in.2 [0.25 mm2]

  • See Line Supply tables for more information!

Digital inputs: Programmable digital inputs Terminal number Logic Voltage level Voltage level, logic’0′ PNP Voltage level, logic’1′ PNP Voltage level, logic ‘0’ NPN Voltage level, logic ‘1’ NPN Maximum voltage on input Input resistance, Ri

4 (6) 18, 19, 27 1), 29, 32, 33,
PNP or NPN 0 – 24 V DC
< 5 V DC > 10 V DC > 19 V DC < 14 V DC
28 V DC approx. 4 k

All digital inputs are galvanically isolated from the supply voltage (PELV) and other high-voltage terminals. 1) Terminals 27 and 29 can also be programmed as output.

Analog inputs: Number of analog inputs Terminal number Modes Mode select Voltage mode

2 53, 54 Voltage or current Switch S201 and switch S202 Switch S201/switch S202 = OFF (U)

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VLT® HVAC Drive Design Guide

Voltage level

Input resistance, Ri

Max. voltage

Current mode

Current level

Input resistance, Ri

Max. current

Resolution for analog inputs

3

Accuracy of analog inputs

Bandwidth

The analog inputs are galvanically isolated from the supply voltage (PELV) and other high-voltage terminals.

: 0 to + 10 V (scaleable) approx. 10 k ± 20 V
Switch S201/switch S202 = ON (I) 0/4 to 20 mA (scalable) approx. 200 30 mA 10 bit (+ sign)
Max. error 0.5% of full scale : 200 Hz

Pulse inputs: Programmable pulse inputs Terminal number pulse Max. frequency at terminal, 29, 33 Max. frequency at terminal, 29, 33 Min. frequency at terminal 29, 33 Voltage level Maximum voltage on input Input resistance, Ri Pulse input accuracy (0.1-1 kHz) Analog output: Number of programmable analog outputs Terminal number Current range at analog output Max. load to common at analog output Accuracy on analog output Resolution on analog output

2 29, 33 110 kHz (push-pull driven) 5 kHz (open collector)
4 Hz see section on Digital input
28 V DC approx. 4 k Max. error: 0.1% of full scale
1 42 0/4 – 20 mA 500 Max. error: 0.8% of full scale 8 bit

The analog output is galvanically isolated from the supply voltage (PELV) and other high-voltage terminals.

Control card, RS-485 serial communication: Terminal number Terminal number 61

68 (P,TX+, RX+), 69 (N,TX-, RX-) Common for terminals 68 and 69

The RS-485 serial communication circuit is functionally separated from other central circuits and galvanically isolated from the supply voltage (PELV).

Digital output: Programmable digital/pulse outputs Terminal number Voltage level at digital/frequency output Max. output current (sink or source) Max. load at frequency output Max. capacitive load at frequency output

2 27, 29 1) 0 – 24 V
40 mA 1 k 10 nF

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Minimum output frequency at frequency output Maximum output frequency at frequency output Accuracy of frequency output Resolution of output frequency

0 Hz 32 kHz Max. error: 0.1% of full scale 12 bit

  1. Terminal 27 and 29 can also be programmed as input.

The digital output is galvanically isolated from the supply voltage (PELV) and other high-voltage terminals.

Control card, 24 V DC output: Terminal number Max. load

12, 13 : 200 mA

3

The 24 V DC supply is galvanically isolated from the supply voltage (PELV), but has the same potential as the analog and digital inputs and outputs.

Relay outputs: Programmable relay outputs Relay 01 Terminal number Max. terminal load (AC-1)1) on 1-3 (NC), 1-2 (NO) (Resistive load) Max. terminal load (AC-15)1) (Inductive load @ cos 0.4) Max. terminal load (DC-1)1) on 1-2 (NO), 1-3 (NC) (Resistive load) Max. terminal load (DC-13)1) (Inductive load) Relay 02 Terminal number Max. terminal load (AC-1)1) on 4-5 (NO) (Resistive load) Max. terminal load (AC-15)1) on 4-5 (NO) (Inductive load @ cos 0.4) Max. terminal load (DC-1)1) on 4-5 (NO) (Resistive load) Max. terminal load (DC-13)1) on 4-5 (NO) (Inductive load) Max. terminal load (AC-1)1) on 4-6 (NC) (Resistive load) Max. terminal load (AC-15)1) on 4-6 (NC) (Inductive load @ cos 0.4) Max. terminal load (DC-1)1) on 4-6 (NC) (Resistive load) Max. terminal load (DC-13)1) on 4-6 (NC) (Inductive load) Min. terminal load on 1-3 (NC), 1-2 (NO), 4-6 (NC), 4-5 (NO) Environment according to EN 60664-1

2 1-3 (break), 1-2 (make)
240 V AC, 2 A 240 V AC, 0.2 A
60 V DC, 1 A 24 V DC, 0.1 A 4-6 (break), 4-5 (make) 240 V AC, 2 A 240 V AC, 0.2 A
80 V DC, 2 A 24 V DC, 0.1 A 240 V AC, 2 A 240 V AC, 0.2 A
50 V DC, 2 A 24 V DC, 0.1 A 24 V DC 10 mA, 24 V AC 20 mA overvoltage category III/pollution degree 2

  1. IEC 60947 part 4 and 5 The relay contacts are galvanically isolated from the rest of the circuit by reinforced isolation (PELV).

Control card, 10 V DC output: Terminal number Output voltage Max. load

50 10.5 V ±0.5 V
25 mA

The 10 V DC supply is galvanically isolated from the supply voltage (PELV) and other high-voltage terminals.

Control characteristics: Resolution of output frequency at 0 – 1000 Hz System response time (terminals 18, 19, 27, 29, 32, 33) Speed control range (open- loop) Speed accuracy (open-loop)

: +/- 0.003 Hz : 2 ms
1:100 of synchronous speed 30 – 4000 rpm: Maximum error of ±8 rpm

All control characteristics are based on a 4-pole asynchronous motor

Surroundings: Enclosure enclosure type D Enclosure enclosure type D, E Enclosure kit available enclosure type D Vibration test Max. relative humidity Aggressive environment (IEC 721-3-3), uncoated Aggressive environment (IEC 721-3-3), coated Test method according to IEC 60068-2-43 H2S (10 days)

IP 00, IP 21, IP 54 IP 21, IP 54
IP 21/TYPE 1/IP 4X top 1.0 g
5%-95% (IEC 721-3-3; Class 3K3 (non-condensing) during operation class 3C2 class 3C3

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VLT® HVAC Drive Design Guide

Ambient temperature (at 60 AVM switching mode) – with derating

max. 55 ° C1)

– with full output power, typical EFF2 motors – at full continuous FC output current

max. 50 ° C1) max. 45 ° C1)

  1. For more information on derating for high ambient temperature AVM and SFAVM, see the Design Guide, section on Special Conditions.

Minimum ambient temperature during full-scale operation

3

Minimum ambient temperature at reduced performance Temperature during storage/transport

Maximum altitude above sea level without derating

Maximum altitude above sea level with derating

32°F [0°C] 14°F [-10°C] -13°-+°149/°158°F [-25°-+65°/70°C] 3280 ft [1000 m] 9842 ft [3000 m]

Derating for high altitude, see section on special conditions.

EMC standards, Emission EMC standards, Immunity

EN 61800-3, EN 61000-6-3/4, EN 55011, IEC 61800-3 EN 61800-3, EN 61000-6-1/2,
EN 61000-4-2, EN 61000-4-3, EN 61000-4-4, EN 61000-4-5, EN 61000-4-6

See section on special conditions!

Control card performance: Scan interval Control card, USB serial communication: USB standard USB plug

: 5 ms
1.1 (Full speed) USB type B “device” plug

Connection to PC is carried out via a standard host/ device USB cable. The USB connection is galvanically isolated from the supply voltage (PELV) and other high-voltage terminals. The USB connection is not galvanically isolated from protection ground. Use only isolated laptop/PC as connection to the USB connector on VLT HVAC Drive or an isolated USB cable/drive.

Protection and Features: · Electronic thermal motor protection against overload. · Temperature monitoring of the heatsink ensures that the adjustable frequency drive trips if the temperature reaches 203°F ± 9°F [95°C ± 5°C]. An overload temperature cannot be reset until the temperature of the heatsink is below 158°F ± 9°F [70°C ± 5°C] (Guideline – these temperatures may vary for different power sizes, enclosures, etc.). VLT HVAC drive has an auto-derating function to prevent it’s heatsink from reaching 203°F [95°C]. · The adjustable frequency drive is protected against short-circuits on motor terminals U, V, W. · If a line phase is missing, the adjustable frequency drive trips or issues a warning (depending on the load). · Monitoring of the intermediate circuit voltage ensures that the adjustable frequency drive trips if the intermediate circuit voltage is too low or too high. · The adjustable frequency drive is protected against ground faults on motor terminals U, V, W.

3.2 Efficiency
Efficiency of VLT HVAC ( VLT)

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3 VLT HVAC Selection

The load on the adjustable frequency drive has little effect on its efficiency. In general, the efficiency is the same at the rated motor frequency fM,N, even if the motor supplies 100% of the rated shaft torque, or only 75% in case of part loads.
This also means that the efficiency of the adjustable frequency drive does not change even if other U/f characteristics are chosen. However, the U/f characteristics influence the efficiency of the motor.
The efficiency declines a little when the switching frequency is set to a value greater than 5 kHz. The efficiency will also be slightly reduced if the line voltage is 480 V, or if the motor cable is longer than 98.43 ft. [30 m].
3
Efficiency of the motor (MOTOR ) The efficiency of a motor connected to the adjustable frequency drive depends on magnetizing level. In general, the efficiency is just as good as with line operation. The efficiency of the motor depends on the type of motor.
In the range of 75-100% of the rated torque, the efficiency of the motor is practically constant, both when it is controlled by the adjustable frequency drive, and when it runs directly on line power.
In small motors, the influence from the U/f characteristic on efficiency is marginal. However, in motors from 15 hp [11 kW] and up, the advantages are significant.
In general, the switching frequency does not affect the efficiency of small motors. The efficiency of motors from 15 hp [11 kW] and up improves by 1-2%. This is because the sine shape of the motor current is almost perfect at high switching frequency.
Efficiency of the system (SYSTEM ) To calculate the system efficiency, the efficiency of VLT HVAC (VLT) is multiplied by the efficiency of the motor (MOTOR): SYSTEM) = VLT x MOTOR
Calculate the efficiency of the system at different loads based on the graph below.

3.3 Acoustic noise
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VLT® HVAC Drive Design Guide

The acoustic noise from the adjustable frequency drive comes from three sources: 1. DC intermediate circuit coils. 2. Integrated fan. 3. RFI filter choke.
Typical values are measured at a distance of 3.28 ft. [1 m] from the unit:

3 A2

Encapsulation

At reduced fan speed (50%) [dBA] *** 51

A3

51

A5

54

B1

61

B2

58

C1

52

C2

55

D1+D3

74

D2+D4

73

E1/E2 *

73

E1/E2 **

82

  • 450 hp [315 kW], 380-480 VAC and 500 hp [355 kW], 525-600 VAC only!

** Remaining E1+E2 power sizes.

*** For D and E sizes, reduced fan speed is at 87%, measured at 200 V.

Full fan speed [dBA] 60 60 63 67 70 62 65 76 74 74 83

3.4 Peak voltage on motor
When a transistor in the inverter bridge switches, the voltage across the motor increases by a du/dt ratio depending on: – the motor cable (type, cross- section, length, shielded or unshielded) – inductance
The natural induction causes an overshoot UPEAK in the motor voltage before it stabilizes itself at a level depending on the voltage in the intermediate circuit. The rise time and the peak voltage UPEAK affect the service life of the motor. If the peak voltage is too high, motors without phase coil insulation are especially affected. If the motor cable is short (by a few yards), the rise time and peak voltage are lower. If the motor cable is long (328 ft. [100 m]), the rise time and peak voltage are higher.
In motors without phase insulation paper or other insulation reinforcement suitable for operation with voltage supply (such as an adjustable frequency drive), fit a du/dt filter or a sine-wave filter on the output of the adjustable frequency drive.
3.5 Special Conditions
3.5.1 Purpose of derating
Derating must be taken into account when using the adjustable frequency drive at low air pressure (high elevations), at low speeds, with long motor cables, cables with a large cross-section or at high ambient temperature. The required action is described in this section.
3.5.2 Derating for Ambient Temperature
The average temperature (TAMB, AVG) measured over 24 hours must be at least 9°F [5°C] lower than the maximum allowed ambient temperature (TAMB,MAX).
If the adjustable frequency drive is operated at high ambient temperatures, the continuous output current should be decreased.

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3 VLT HVAC Selection

The derating depends on the switching pattern, which can be set to 60 AVM or SFAVM in parameter 14-00.

A enclosures 60 AVM – Pulse Width Modulation

SFAVM – Stator Frequency Asyncron Vector Modulation

3

Figure 3.1: Derating of Iout for different TAMB, MAX for enclosure A, using 60 AVM

Figure 3.2: Derating of Iout for different TAMB, MAX for enclosure A, using SFAVM

In enclosure A, the length of the motor cable has a relatively high impact on the recommended derating. Therefore, the recommended derating for an application with max. 32 ft. [10 m] motor cable is also shown.

Figure 3.3: Derating of Iout for different TAMB, MAX for enclosure A, using 60 AVM and maximum 32 ft [10 m] motor cable

Figure 3.4: Derating of Iout for different TAMB, MAX for enclosure A, using SFAVM and a maximum of 32 ft. [10 m] motor cable

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3 VLT HVAC Selection
B enclosures 60 AVM – Pulse Width Modulation

VLT® HVAC Drive Design Guide
SFAVM – Stator Frequency Asyncron Vector Modulation

3

Figure 3.5: Derating of Iout for different TAMB, MAX for enclosure B, using 60 AVM in normal torque mode (110% over torque)
C enclosures 60 AVM – Pulse Width Modulation

Figure 3.6: Derating of Iout for different TAMB, MAX for enclosure B, using SFAVM in normal torque mode (110% over torque)
SFAVM – Stator Frequency Asyncron Vector Modulation

Figure 3.7: Derating of Iout for different TAMB, MAX for enclosure C, using 60 AVM in normal torque mode (110% over torque)
D enclosures 60 AVM – Pulse Width Modulation, 380-480 V

Figure 3.8: Derating of Iout for different TAMB, MAX for enclosure C, using SFAVM in normal torque mode (110% over torque)
SFAVM – Stator Frequency Asyncron Vector Modulation

Figure 3.9: Derating of Iout for different TAMB, MAX for enclosure D at 480 V, using 60 AVM in normal torque mode (110% over torque)

Figure 3.10: Derating of Iout for different TAMB, MAX for enclosure D at 480 V, using SFAVM in normal torque mode (110% over torque)

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VLT® HVAC Drive Design Guide
60 AVM – Pulse Width Modulation, 525-600 V (except P315)

3 VLT HVAC Selection
SFAVM – Stator Frequency Asyncron Vector Modulation

Figure 3.11: Derating of Iout for different TAMB, MAX for enclosure D at 600 V, using 60 AVM in normal torque mode (110% over torque). Note: not valid for P315.
60 AVM – Pulse Width Modulation, 525-600 V, P315

3
Figure 3.12: Derating of Iout for different TAMB, MAX for enclosure D at 600 V, using SFAVM in normal torque mode (110% over torque). Note: not valid for P315.
SFAVM – Stator Frequency Asyncron Vector Modulation

Figure 3.13: Derating of Iout for different TAMB, MAX for enclosure D at 600 V, using 60 AVM in normal torque mode (110% over torque). Note: P315 only.
E enclosures 60 AVM – Pulse Width Modulation, 380-480 V

Figure 3.14: Derating of Iout for different TAMB, MAX for enclosure D at 600 V, using SFAVM in normal torque mode (110% over torque). Note: P315 only.
SFAVM – Stator Frequency Asyncron Vector Modulation

Figure 3.15: Derating of Iout for different TAMB, MAX for enclosure E at 480 V, using 60 AVM in normal torque mode (110% over torque)

Figure 3.16: Derating of Iout for different TAMB, MAX for enclosure E at 480 V, using SFAVM in normal torque mode (110% over torque)

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60 AVM – Pulse Width Modulation, 525-600 V

VLT® HVAC Drive Design Guide
SFAVM – Stator Frequency Asyncron Vector Modulation

3
Figure 3.17: Derating of Iout for different TAMB, MAX for enclosure E at 600 V, using 60 AVM in normal torque mode (110% over torque).

Figure 3.18: Derating of Iout for different TAMB, MAX for enclosure E at 600 V, using SFAVM in normal torque mode (110% over torque).

3.5.3 Derating for Low Air Pressure
The cooling capability of air is decreased at a lower air pressure.
At altitudes higher than 6,600 feet [2 km], please contact Danfoss Drives regarding PELV.
At an altitude lower than 3,280 ft [1,000 m], no derating is necessary; but at an altitude higher than 3,280 ft [1,000 m], the ambient temperature (TAMB) or max. output current (Iout) should be derated in accordance with the diagram shown.

Figure 3.19: Derating of output current versus altitude at TAMB, MAX. At altitudes higher than 6,600 feet [2 km], please contact Danfoss Drives regarding PELV.
An alternative is to lower the ambient temperature at high altitudes and thereby ensure 100% output current at high altitudes.
3.5.4 Derating for Running at Low Speed
When a motor is connected to an adjustable frequency drive, it is necessary to make sure that the cooling of the motor is adequate. A problem may occur at low RPM values in constant torque applications. The motor fan may not be able to supply the required volume of air for cooling, which limits the torque that can be supported. Therefore, if the motor is to be run continuously at an RPM value lower than half of the rated value, the motor must be supplied with additional air-cooling (or a motor designed for this type of operation may be used).

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An alternative is to reduce the load level of the motor by choosing a larger motor. However, the design of the adjustable frequency drive limits the motor size.

3.5.5 Derating for Installing Long Motor Cables or Cables with Larger Cross- Section

The maximum cable length for this adjustable frequency drive is 984 ft [300 m] for unshielded cable, and 492 ft [150 m] for shielded cable.

The adjustable frequency drive has been designed to work using a motor cable with a rated cross-section. If a cable with a larger cross-section is used,

3

reduce the output current by 5% for every step the cross-section is increased.

(Increased cable cross-section leads to increased capacity to ground, and thus an increased ground leakage current).

3.5.6 Automatic adaptations to ensure performance
The adjustable frequency drive constantly checks for critical levels of internal temperature, load current, high voltage on the intermediate circuit and low motor speeds. As a response to a critical level, the adjustable frequency drive can adjust the switching frequency and/or change the switching pattern in order to ensure the performance of the drive. The capability to automatically reduce the output current extends the acceptable operating conditions even further.
3.6 Options and Accessories
Danfoss offers a wide range of options and accessories for the VLT adjustable frequency drives.

3.6.1 Mounting Option Modu

References

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