DOLD UH 5892 IMD Varimeter Insulation Monitor Instructions

: June 13, 2024
: DOLD

Table of Contents

DOL D UH 5892 IMD Varimeter Insulation Monitor
Product Information
Product Usage Instructions
Product Description
Function Diagram
Function
Circuit Diagrams
Connection Terminals
Notes
Technical Data
Technical Data
Options with Pluggable Terminal Blocks
Accessories
Connection Examples
Characteristic
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DOL D UH 5892 IMD Varimeter Insulation Monitor

Product Information

The VARIMETER IMD Insulation monitor UH 5892 is a monitoring device used to measure the resistance to earth in ungrounded DC systems. It is designed to ensure the safety and proper functioning of electrical systems by monitoring insulation resistance.
The device is equipped with an auxiliary voltage supply and features green and red LED indicators to provide visual feedback on the status of the measurement. It also has a reset button for manual or automatic reset of the alarm.
The measuring circuit involves connecting terminals L(+) and L(-) to the mains to be monitored, and terminals PE1 and PE2 to the protective conductor system. An active measuring voltage with alternating polarity is applied between L(+)/L(-) and PE1/PE2 to measure the insulation resistance.

Product Usage Instructions

Connect terminals A1(+) and A2 to the auxiliary voltage supply.
Observe the green LED indicator to ensure the auxiliary supply is connected.
Allow a 10-second start-up delay for the measuring circuit to initialize.
Connect terminals L(+) and L(-) to the mains to be monitored.
Connect terminals PE1 and PE2 to the protective conductor system via separate lines.
Ensure that the measuring circuit is active and measuring the insulation resistance.
Observe the red LED indicator for any alarms. If the resistance is below the response value, the red LED will be on.
If an alarm is triggered, you can perform a manual reset by pressing the reset button.
For automatic reset, ensure that X5/LT1 is bridged. This will enable the device to reset automatically once the fault is resolved.
Monitor the approximated value of the actual resistance to ground (PE) using the LED-chain indicators.

Note : Please refer to the product manual for detailed circuit diagrams, connection terminals, and technical specifications.

Product Description

The insulation monitor UH 5892 of the series varimeter IMD monitors the ground resistance of isolated DC-voltage systems (IT-systems) with nominal voltage up to DC 600 V. The unit detects symmetrical as well as unsymmetrical faults. The separate auxiliary supply of AC/DC 24 … 60 V or AC/DC 85 … 230 V allows also monitoring when the system is without voltage. To indicate the actual ground resistance value the unit has an LED chain and an analogue output. When a fault is detected the relay switches and the red LED Alarm lights up, The device can be used for system with leakage capacities up to 20 uF.

Function Diagram

Your Advantages

Preventive fire and system protection
Insulation monitoring of DC and AC-systems up to DC 600 V
And AC 400 V nominal voltage
No additional coupling device required
Suitable for leakage capacitances up to 20 µF
Monitoring also with voltage-free mains
2 wide voltage input ranges for auxiliary voltage

Features

Insulation monitoring according to IEC/EN 61557-8
Detection of symmetric and asymmetric insulation faults
1 changeover contact for alarm
Fixed response value RAN: 50 kΩ, other on request
Internal reset and test pushbutton
External test and reset pushbutton can be connected
LED indicator for auxiliary voltage and alarm
LED chain to indicate the current insulation resistance
Automatic or manual reset, programmable
Analogue output for insulating value
External indicating instrument can be connected
Closed circuit operation
Open circuit operation on request
With pluggable terminal blocks for easy exchange of devices – With screw terminals
- Or with cage clamp terminals
Width 45 mm

Approvals and Markings

Applications

Monitoring of the resistance to earth in ungrounded DC systems

Function

The device is supplied with auxiliary voltage via terminals A1(+)/A2; ea green “ON” LED comes on. After connecting the auxiliary supply a 10 s start up delay is active allowing the measuring circuit to start.
After this, measurement of the insulation resistance in the measuring circuits begins.

Measuring circuit
(Insulation measurement between terminals L(+)/L(-) and PE1/PE2).

Terminals L(+) and L(-) are connected to the mains to be monitored. In addition, the two terminals PE1 and PE2 must be connected to the protective conductor system via separate lines. An active measuring voltage with alternating polarity is applied between L(+)/L(-) and PE1/PE2 to measure the insulation resistance. The length of the positive and negative measuring phases has a fixed factory setting of 16 s (max. leakage capacitance of 20µF). The LED-chain and the analogue output show the actual determined insulating resistance, and the output relays witch according to the respective response values set. If the response thresholds has been undercut the red LED “Alarm” lights up.

Indicators

Green LED “ON”: On, when auxiliary supply connected
Red LED “Alarm”: On, when resistance is below the response value RAN
LED-chain: The approx. value of actual rsistance to ground (PE)

Circuit Diagrams

Connection Terminals

DOLD UH 5892 IMD Varimeter-Insulation-Monitor-FIG-16

Notes

Risk of electrocution!
Danger to life or risk of serious injuries.

Disconnect the system and device from the power supply and ensure they remain disconnected during electrical installation.
The terminals of the control input X5, LT1, LT2, PT1 and PT2 have no galvanic separation to the measuring circuit L(+) and L(-) and are electri-cally connected together, therefore they have to be controlled by volt free contacts or bridge. These contacts ore bridges must provide a sufficient separation depending on the mains voltage on L(+)-L(-).
No external potentials may be connected to control terminals X5, LT1, LT2, PT1 and PT2.
The terminals of the control input X3 and X4 have no galvanic separation to the measuring circuit L(+) and L(-) and are electrically connected to-gether, therefore they have to be controlled by volt free contacts or bridge. Connected devices/indicators must provide a sufficient separation de-pending on the mains voltage on L(+)-L(-).

Attention!

Before checking insulation and voltage, disconnect the monitoring device UH 5892 from the power source!
In one voltage system only one insulation monitor can be used. This has to be observed when interconnecting two separate systems.
The device must not be operated without PE1/PE2 connection!
On fluctuation of the mains voltage momentary false readings can occur.
This is normal and caused by the cyclic measuring principle.

Attention!

If a monitored AC system includes galvanically connected DC circuits (e.g. via a rectifier), an insulation failure on the DC side can only be detected correctly, when a current of min 10 mA can flow via the semi-conductor connections.
If a monitored DC system includes galvanically connected AC circuits (e.g. via an inverter), an insulation failure on the AC side can only be detected correctly, when a current of min 10 mA can flow via the semi-conductor connections.
The response value RAN is fixed. An external indicator instrument can be connected.
The unit works de-energized on trip, that means, the output relay relase in position of rest at a insulation failures RE < RAN).
A bridge between X5 and LT1 allows to select auto or manual reset. The UH 5892 has a built in reset button on the front and allows connection of an external button at terminals LT1 and LT2 also.
For function test an external (terminals PT1-PT2) or built in push button can be used to simulate a ground fault. The push button has to be pressed for the length of a measuring period.
The analogue output (terminals X3 and X4) provides a voltage signal proportional to the actual insulation resistance of the mains. The following formula describes the input to output ratio:

These values for UA are valid for CE = 0 (see characteristic). In practice it makes no sense to monitor values above 11 … 12 V as the tolerances increase, especially with mains capacity.

Technical Data

Auxiliary circuit

Auxiliary voltage U H| Voltage range| Frequency range
---|---|---
AC/DC 24 … 60V| AC 19 … 68 V| 45 … 400 Hz; DC 48 % W)
DC 18 … 96 V| W) £ 5 %
AC/DC 85 … 230 V| AC 65 … 276 V| 45 … 400 Hz; DC 48 % W)
DC 75 … 300 V| W) £ 5 %
*) W = Permitted residual ripple of auxiliary supply