Spellman UM8-40 Series High Voltage Power Supply Instruction Manual

Spellman UM8-40 Series High Voltage Power Supply

IMPORTANT SAFETY PRECAUTIONS

SAFETY

• THIS POWER SUPPLY GENERATES VOLTAGES THAT ARE DANGEROUS AND MAY BE FATAL. OBSERVE EXTREME CAUTION WHEN WORKING WITH THIS EQUIPMENT.
• High-voltage power supplies must always be grounded.
• Do not touch connections unless the equipment is off and the
• The capacitance of both the load and power supply is discharged.
• Allow five minutes for the discharge of the internal capacitance of the power supply.
• Do not ground yourself or work under wet conditions.

SERVICING SAFETY

• Maintenance may require removing the instrument cover with the power on.
• Servicing should be done by qualified personnel aware of the electrical hazards.
• The WARNING note in the text calls attention to hazards in the operation of these units that could lead to possible injury or death.
• CAUTION notes in the text indicate procedures to be followed to avoid possible damage to equipment.

Copyright © 2000, Spellman High Voltage Electronics Corporation. All Rights Reserved. This information contained in this publication is derived in part from proprietary and patent data. This information has been prepared for the express purpose of assisting operating and maintenance personnel in the efficient use of the model described herein, and publication of this information does not convey any right to reproduce it or to use it for any purpose other than in connection with installation, operation, and maintenance of the equipment described.

INTRODUCTION

Description of the UM8-40 Series
Spellman’s UM8-40 Series of printed circuit board mountable, high voltage modules offer a form, fit, and function replacement for presently available commercially made units while providing additional features and benefits. Utilizing proprietary power conversion technology these SMT-based high-voltage modules provide improved performance, reliability, and easy system integration.

The UM8-40 is available in three power ranges of 4, 15, and 30 watts with output voltages spanning from 15kV to 40kV with fixed positive or negative polarities. Voltage & Current loops with automatic cross-over control regulate the output into any load condition. The UM8-40 is a reliable and robust series that is arc and short-circuit-protected. The comprehensive standard interface provides interfacing flexibility and all UM8-40 units are CE and RoHS compliant.

Standard Features
The UM8-40 Series incorporates several standard features designed to optimize user satisfaction and safety:

• Slow Start: A 10 millisecond slow start time constant assures quick yet fully controllable rise time of the high voltage output.
• Current Regulating Loop: Current programmability allows the user to set where the unit will current limit, anywhere from 0 to 100% of maximum rated current.
• 0 to +4.64Vdc Programming Inputs: Positive polarity, high impedance, ground referenced 0 to 4.64Vdc voltage programming inputs correspond to 0 to 100%rated voltage and current outputs.
• 0 to +4.64Vdc Monitor Outputs: Positive polarity, low impedance, ground referenced 0 to 4.64Vdc voltage monitor outputs correspond to 0 to 100% rated output voltage and current.
• Precision +5Vdc Reference Output: A precision micropower bandgap reference of +5Vdc, ±0.5%, 25ppm/°C with an output impedance of 475Ω is provided to simplify remote programming of the power supply.
• Arc and Short Circuit Protected: Due to the fixed, high-frequency conversion rate the UM8-40s output capacitance is small resulting in minimal stored energy. Through the use of generously rated surge limiting resistors and a ffast-actingcurrent loop, all units are fully arc and short circuit protected.

Remote Operating Features

• Enable Input: The Enable Input allows the user to easily control the HV ON/HV OFF status of the power supply. HCMOS compatible signals A low (<1.5Vdc) enabled input signal equals HV OFF, while a high (open or >3Vdc) enabled signal equals HV ON.

Warning!
The Enable Input should not be used for protection against user injury or a safety interlock function.

Options
Several standard options are available to customize your UM for your application.

• Option – Legacy Interface
• Option – Low-Temperature Coefficient
• M Option – Mu Metal Shield
• S Option – RF Tight Shielded Can
• E Option – Eared Mounting Plate
• X Numbered Units – Custom Options

Interpreting the Model Number
The power supply model number describes its capabilities. Model numbers are configured as follows:

UM25P15/L/E where:

• UM is the product series name
• 25 is the maximum output voltage in kV
• P is the output polarity
• 15 is the output power in watts
• L is the Legacy Interface
• E is the Eared Mounting Plate

X-numbered units are unique units custom-developed for specific application requirements above and beyond the scope of the available standard options. Each 4-digit X number corresponds to an applicable specification control drawing.

INSPECTION & INSTALLATION

Initial inspection and preliminary checkout procedures are recommended. For safe operation, please follow the procedures described in Chapter 3, Operating Instructions.

Initial Inspection
Inspect the packaging exterior for evidence of damage due to improper handling in transit. Notify the carrier and Spellman High Voltage immediately if damage is evident. Do not destroy or remove any of the packing material used in a damaged shipment. After unpacking inspect the power supply for any visible signs of damage.

Mechanical Installation
Standard UM8-40 modules are intended for direct printed circuit board mounting, it is recommended that the unit be processed in a hand solder operation only. Solder iron tip temperatures are most commonly between 315-371°C (600-700°F) for Sn63/Pb37 alloys and between 371-427°C (700-800°F) for Sn96.5/Ag3.0/Cu0.5 lead-free alloys. Heat both the land area and component lead to be soldered with the iron before adding cored wire. Apply the solder wire to the land area or component lead. Do not apply the wire directly to the soldering iron tip. Do not apply solder iron to the joint for a period exceeding 15 seconds. Process and inspect workmanship to IPC-A-610 class 2 standards as applicable. 2-56 pan-head stainless steel screws are provided to mechanically secure the unit to the printed circuit board assembly. Tighten the screws to 3 inches/pounds (0.34N•m) of torque. Do not use longer screws than those provided, otherwise, the risk of damage to the unit is possible. The mounting screws are electrically isolated, they are not connected to any potential or ground point inside the power supply. Please see the UM8-40 data sheet for a more detailed dimensional drawing.

Temperature Consideration
Connection cooled typically. 30-watt units operating at full power might require additional cooling to maintain case temperature below 65°C. Methods may include Forced air cooling, use of a heat sink or metal case, etc. It is the user’s responsibility to maintain the case temperature below 65°C. Damage to the power supply due to inadequate cooling is considered misuse and repairs will not be covered under warranty.

Operating Instructions

Operation

WARNING!

This equipment generates dangerous voltages that may be fatal. Proper grounding of all high-voltage equipment is essential. It is highly recommended that all testing comply with IEEE Standard 510-1983 IEEE Recommended Practices for Safety in High Voltage and High Power Testing. A copy of this standard can be downloaded from the Spellman High Voltage website here.

INPUT VOLTAGE
Check the identification label on the power supply and confirm it matches the input voltage of the source supply that will be used to power the UM8-40 module. 4-watt units operate off +12Vdc, while 15 and 30-watt units operate off +24Vdc. If a 4-watt unit is connected to +24Vdc, the unit will operate properly meeting all specifications. If a 15 or 30-watt unit is connected to +12Vdc, no damage will occur but the unit may not perform properly.

HIGH VOLTAGE CONNECTION
Ensure that the high voltage connection is properly terminated to the load. Confirm that adequate air isolations spacings exist for the maximum voltage of the power supply, using the guideline of 10kV per inch (25.4mm) to any points that will be elevated to high voltage. All accessible high-voltage points should be enclosed in a protective Faraday enclosure. Any access panels on the safety enclosure should be interlocked.

GROUNDING
Proper grounding of the unit is essential for reliable operation. Power Ground, Signal Ground, and HV Ground Return are connected internally. For best performance, they should not be connected externally. The Power Ground connection (Pin 1) carries the +12Vdc or +24Vdc current that powers the unit, making this connection adequate to handle 2 amps, minimum. Additionally, it is recommended that this connection be used to tie the power supply to whatever potential is used as the local “system ground”. Signal grounds relating to programming and monitor functions should be referenced to the UM8-40’s Signal Ground (Pin5). A physical load return connection must be made from the bottom of the load to the power supplies HV Ground Return (Pin 8). See Figure 2 for details.

OPTIONS
See Section 5 of this manual for setup and operating instructions if the unit under test has any options. Custom X numbers units may also require special test requirements; consult the unit’s specification control drawing for details.

SIGNAL CONNECTIONS
Connect the appropriate programming and monitoring signals to the unit as detailed in the figures in this chapter.

INITIAL TURN ON

• Set the voltage and current programming inputs for zero output (Pin 6A and 5A respectively). Ground the Enable Input (Pin 4), to assure the unit is in HV OFF mode.
• The DC input power can now be connected.
• Enable the power supply by opening the Enable Input (Pin 4).
• Set the current programming level (Pin 5A) to just above the current anticipated that will be drawn from the power supply or leave open for preset current to 103% of rated current.
• Slowly increase the voltage programming (Pin 6A) while monitoring the voltage and current monitors (Pin 4A and 3A respectively). Carefully note proper equipment operation and that the load is behaving as predicted.
• To turn the HV OFF ground the Enable Input (Pin 4). If the equipment is to be left off for an extended period of time or service of the unit or load is required turn off the DC input power.

Legacy Interface Units:
Negative output polarity units are programmed such that 5.0Vdc to 0.36Vdc equals 0 to 100% of rated output voltage

WARNING!
After turn off do not touch anything that has been connected to the output of the power supply. Wait a minimum of 5 minutes, and then discharge any remaining stored energy by connecting the high voltage output to ground. Failure to follow these safety warnings can result in injury or death.

Standard Features
Programming and monitoring of the UM8-40 is accomplished via the use of conventional positive polarity, ground-referenced signals. All signal inputs and outputs are noise filtered, impedance protected and diode clamped providing an easy-to-use, robust analog customer interface. Excellent results have been obtained via the use of standard engineering design guidelines like twisted pair, shielded cables, the prudent dressing of interface wiring away from possible noise sources, short cable runs and adherence to a well-thought- out and executed grounding topology.

REMOTE PROGRAMMING
The UM8-40’s programming and monitor signals are based upon a universal, positive polarity, ground-referenced signal such that 0 to 4.64Vdc corresponds to 0 to 100% rated output. Programming can be accomplished via the use of an applicable customer provided ground referenced voltage source that meets the mentioned requirements. See Figure 3 for details. If such a source is not available a precision +5Vdc reference is provided on Pin 7. A simple adjustable voltage divider can be created using this reference and an external potentiometer(s) which will provide full control of the voltage and current loops. See Figure 4 for details.

REMOTE MONITORING
The voltage and current monitor signals have adequate bandwidth capability to accurately represent the actual respective output within the dynamic limits of the power supply. See Figure 5 for details.

ENABLE INPUT
The enable input signal provides simple control of the ON/OFF functionality of the high-voltage output. See Figure 6 for details.

WARNING!
It is extremely dangerous to use this circuit to inhibit high voltage generation to service or approach any area considered unsafe during normal usage.

OT OUTPUT
The UM8-40 is protected with a thermostat that will disable the generation of high voltage if an internal temperature of ≥65 degree C is sensed. This latching circuit will require the removal and reapplication of the input power to clear the fault, along with the power supply case dropping below 55 degrees C. An Over Temperature Output fault signal is provided on pin 2A. This signal will go high, sourcing +5Vdc @ 1mA (provided through a 1kΩ series resistance) to indicate the power supply has terminated the generation of high voltage due to an over temperature condition. If this OT fault condition exists most likely the unit requires additional cooling, see section 2.3 “Temperature Considerations” in this manual for additional details and recommendations.

Note:
The +5V reference output (pin 7) is provided via an internal 4752 inline series resistor for transient and short circuit protection. Take this impedance into account when selecting the resistance value of external programming potentiometers. Use 20K pots if both voltage and current adjustments are used as shown above. Use a 10K pot if only one pot is used and the other programming input is pulled up directly to +5V. The use of excessively low resistance values of programming potentiometers will create a significant voltage divider against the internal 4750 series resistor resulting in the inability to program the power supply to its maximum voltage and current outputs.

Principles of Operation

Warning!
The energy levels used and generated by the power supply can be lethal! Do not attempt to operate the power supply unless the user has sufficient knowledge of the dangers and hazards of working with high voltage. Do not attempt to approach or touch and circuits that are connected to or have been connected to the power supply. Be certain to discharge any stored energy that may be present before and after the power supply is used. Consult IEEE recommended practices for safety in high voltage testing document number 510-1983.

DC Input
The UM8-40 is a DC to DC converter. Within the power supply conversions from low voltage DC, to low voltage AC, to high voltage AC and finally to high voltage DC takes place. The DC input (either +12Vdc or +24Vdc) powers both the power conversion circuitry that creates the high voltage output, along with the low voltage DC housekeeping voltages that provide power to the affiliated support control circuitry.

Inverter
The DC input voltage is fed to the Inverter circuitry. Here the low-voltage DC is converted to a low-voltage, high-frequency AC signal. This power conversion step allows for all subsequent power processing to take advantage of component miniaturization due to the high operational frequency. The Inverter functionality is controlled via the power supplies regulating loops which allows for complete command of the desired output voltage and current.

High Voltage Transformer
The high-voltage transformer is a ferrite core step up type in which the primary is driven from the output of the Inverter circuit. The secondary of the high voltage transformer feeds the High Voltage Output Section.

High Voltage Output Section
The High Voltage Output Section utilizes an arrangement of half-wave Cockcroft-Walton voltage multiplier stages to obtain the necessary output voltage.
The actual output voltage is sampled via a high-impedance divider to create a voltage feedback signal. A current feedback signal is created via a current sense resistor in the low-end return of the High Voltage Output Circuitry. These two accurate ground referenced feedback signals are used to precisely regulate and control the unit, in addition to providing external monitoring.

Control Circuitry
Various SMT-based control circuitry is used for all interfacing, monitoring and regulation functionality of the UM8-40 modular power supply. The voltage and current feedback signals generated in the High Voltage Output Section are compared to the requested voltage and current commands from the remote interface. The voltage or current loop error amplifier creates the appropriate error signal which is provided to the Pulse Width Modulation (PWM) circuitry. The output of the PWM circuitry drives the Inverter circuit to provide the required output in a continuous closed-loop control process, regulating in either voltage mode or current mode as required.

The internally generated voltage and current feedback signals are processed and provided to the remote interface for monitoring purposes. The Enable Input from the remote interface controls the HV ON and HV OFF status of the power supply by interfacing with the PWM circuitry.A precision +5Vdc, ±0.5%, 25ppm/°C micro power band gap reference output is provided for user programming convenience.

OPTIONS

L Option – Legacy Interface

The Legacy Interface provides form, fit and function replacement for presently available commercially made units. The standard UM8-40 is provided with a row of 13 interface pins on 0.1” center spacing. By removing “every other pin” the Legacy Interface provides 7 pins on 0.2” center spacing. Physically the UM8-40 with the Legacy Interface will fit into printed circuit boards designed for other commercially made units. A standard unit can be turned into a Legacy Interface unit by clipping the appropriate interface pins. Functionality wise the Legacy Interface is electrically identical to other commercially made units so interface compliance is guaranteed.

T Option – Low-Temperature Coefficient
The T Option offers the UM8-40 with an improved temperature coefficient. The standard voltage feedback divider is replaced with one having a superior temperature coefficient, resulting in a unit with 25ppm/C° (typical) temperature coefficient.

M Option – Mu Metal Shield

The M Option fits the UM8-40 with an adhesive-backed Mu Metal foil shield to help protect sensitive adjacent circuitry. See data sheet for dimensional drawing.

S Option – RF Tight Shielded Can

The S Option mounts the UM8-40 module inside of a flanged RF-tight aluminum can. See the data sheet for dimensional drawing.

E Option – Eared Mounting Plate

An eared mounting plate is affixed to the top surface of the UM8-40 module allowing simple chassis mounting of the unit. See the data sheet for dimensional drawing.

B Option – Terminal Block

The B Option provides terminal block connections for the customer interface and high-voltage return. Acceptable wires range from 20AWG to 26AWG. See the data sheet for dimensional drawing.

X Numbered Units – Custom Options
When modification requirements of standard units are beyond the scope of standard options a custom unit is created. To accurately capture the details Spellmancreates a unique Specification Control Drawing. This drawing outlines all items (mechanical, electrical, etc) that differ from a standard unit. These units will be designated as an X-numbered unit. An X-numbered unit will have an X number in its model number, like X1234. Together the UM8-40 data sheet and the applicable Specification Control Drawing will detail the parameters of these proprietary custom units.

MAINTENANCE

WARNING!
This power supply generates voltages that are dangerous and may be fatal. Observe extreme caution when working with high voltage.

Periodic Servicing
The UM8-40 product family does not require any periodic maintenance or servicing.

Performance Testing

WARNING!
High Voltage is dangerous. Only qualified personnel should perform these tests. It is highly recommended that all testing comply with IEEE Standard 510-1983 IEEE Recommended Practices for Safety in High Voltage and High Power Testing. A copy of this standard can be downloaded from the Spellman High Voltage website here.

Generalized high voltage test procedures are described in Bulletin STP-783, Standard Test Procedures for High Voltage Power Supplies. A copy of this bulletin can be downloaded from the Spellman High Voltage website here.

Test equipment includes, but is not limited to: an oscilloscope, a high impedance digital volt meter, a current meter, a ripple checker, a high voltage load, a high voltage divider (such as the Spellman HVD-100 or HVD-200) an insulated load stick and insulated short circuit stick and a safety interlocked Faraday test cage to safety conduct the tests inside of. All equipment must be properly rated for the power supply to be tested. If you do not possess the required equipment and skills necessary to safely conduct these tests do not attempt to perform these performance tests.

High Voltage Dividers

High voltage dividers for precise measurements of output voltage with accuracy up to 0.1% are available from Spellman. The HVD-100 is used for voltages up to 100KV, the HVD-200 measures up to 200KV. The HVD Series of high voltage dividers are designed for use with differential voltmeters or high-impedance digital voltmeters. The high input impedance of the HVD Series is ideal for measuring high voltage low current sources, which would be overloaded by traditional lower impedance dividers.

The HVD Series data-sheet can be downloaded from the Spellman High Voltage website here. Contact the Spellman Sales Department for information on price and availability.

FACTORY SERVICE

Warranty Repairs
During the Warranty period, Spellman will repair all units free of charge. The Warranty is void if the unit is worked on by other than Spellman personnel. See the Warranty in the rear of this manual for more information. Follow the return procedures described in Section 7.2. The customer shall pay for shipping to and from Spellman.

Factory Service Procedures
Spellman has a well-equipped factory repair department. If a unit is returned to the factory for calibration or repair, a detailed description of the specific problem should be attached. For all units returned for repair, please obtain an authorization to ship from the Customer Service Department, either by phone or mail prior to shipping. When you call, please state the model and serial numbers, which are on the plate on the rear of the power supply, and the purchase order number for the repair. A Return Material Authorization Code Number (RMA Number) is needed for all returns. This RMA Number should be marked clearly on the outside of the shipping container. Packages received without an RMA Number will be returned to the customer. The Customer shall pay for shipping to and from Spellman. A preliminary estimate for repairs will be given by phone by Customer Service. A purchase order for this amount is requested upon issuance of the RMA Number. A more detailed estimate will be made when the power supply is received at the Spellman Repair Center. In the event that repair work is extensive, Spellman will call to seek additional authorization from your company before completing the repairs.

Shipping Instructions
All power supplies returned to Spellman must be sent shipping prepaid. Pack the units carefully and securely in a suitable container, preferably in the original container, if available. The power supply should be surrounded by at least four inches of shock absorbing material. Please return all associated materials, i.e. high voltage output cables, interconnection cables, etc., so that we can examine and test the entire system. All correspondence and phone calls should be directed to: Spellman High Voltage Electronics Corp. 475 Wireless Boulevard

Hauppauge, New York 11788

• TEL: 631-630-3000
• FAX: 631-435-1620
• E-Mail: sales@Spellmanhv.com

To obtain information on Spellman’s product warranty please visit our website at: http://www.spellmanhv.com/en/About/Warranty.aspx

• MODEL :
• SERIAL# :
• DATE :

SPELLMAN HIGH VOLTAGE ELECTRONICS CORPORATION
475 Wireless Blvd. Hauppauge, New York, 11788 +1(631) 630-3000FAX: +1(631) 435-1620

• E-mail: sales@spellmanhv.com
• Website: www.spellmanhv.com

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