Voltage Monitor – Type 8539

With two limits


The voltage monitor type 8539, part no. 23018x two limits can independently monitor.

Due to the high input impedance (about 2 Mohm) and the high over-voltage strength, the device is such as to monitor the voltage of contact line systems.
When running part no. 23018x the output relay is activated only when the voltage value, longer than the predetermined time constant is present and the unit is in operation.


The monitoring device part no. 23018x measures the voltage at the monitored site. Decreases or increases the measured voltage is below or above one of the selected limits, this is registered by the device. If the limit for a period of time set permanently at or exceeded, the output of the relay K1 or K2 will change accordingly.

If the threshold is exceeded again, so the relays K1 and K2 are delayed in their normal position and switch on again when the above conditions are met again.



The monitor is delivered with a limit value of DC 200 V for K1 and K2 for DC 400V.
The voltage source to be monitored is to connect (eg between contact line systems and rail or similar).

The supply voltage of the device (AC or DC depending on model) must be connected.

Reprogramming thresholds:
After applying the desired limit as measured voltage at the test voltage input, the learning process (programming) to start the device.

By pressing the „Prog1“ / „Prog2“ (> 3s) a learning procedure is started. To program the switch points and delay times for K1 and K2, see overleaf.
The learning procedure takes less than 10 s, the parameters are stored until an appropriate new programming and permanently retained even after power failure.
The times are programmed at the above and below the threshold.
The contact display on the device corresponds to the position when no voltage is applied.

Other monitoring equipment see complete brochure folder.

Do you have any questions?
We will be happy to answer you!