Voltage Monitor – Type 8539

EKS version


The voltage monitoring unit part number 230144 is used in earthing short-circuit units to measure the potential difference between the earthing systems applied and to trigger the switching process if the set voltage threshold is exceeded.

The unit is especially suitable for this type of application due to the high input resistance (approx. 2 MΩ) and its ability to withstand high overvoltages.
In part number 230144 the output relay is activated if the preset voltage value is exceeded and the unit is in operation. Mains failures, errors, etc., do not lead to unwanted false alarms.


The voltage monitoring unit part number 230144 measures the voltage at the point to be monitored (for example, between the running rail and earth). If the measured voltage rises to above the preset threshold value, this is noted by the unit and the output relay is triggered.

If the threshold value is exceeded again, the trigger point changed or the supply voltage switched off and on gain, the output relay drops out without any delay and is only drawn in again once the above-mentioned conditions have been met again.


Initial commissioning

The monitoring unit is connected to the measured voltage source to be monitored and the operating voltage (supply voltage) applied. Once the measured voltage that is desired as the threshold value has been applied to the measured value input, then the teach-in process (programming) of the unit can begin.

The teach-on procedure is started by pressing the »PROG« button. The yellow LED flashes during the teach-in procedure. The unit operates when the LED goes out. The teach-in process takes approx. 20 – 30 seconds.

The parameters are saved permanently until programming is done again and are still retained if the mains power supply fails.The contact display at the unit corresponds to the function under the conditions illustrated.



The two-button selector switch on the front of the unit is not functional in this device variation part no. 230144.

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