Voltage Monitor – Type 8539

DC 1500 V


The voltage monitoring device of the type 8539 with the article numbers 23014x and 23016x has been developed exclusively for the voltage level DC 1500 V. All relevant clearances and creepage distances have been so dimensioned that the test voltage amounts to DC 9.5 kV for all measurements.

The voltage monitoring device of the type 8539 with the article numbers 23014x and 23016x is usually used to indicate or trigger switching operations if the voltage is below the set voltage threshold.

Due to the high input resistance (approx. 4 MΩ) and the high overvoltage capability the device is suited e.g. for monitoring the residual voltage on traction power supply systems.

In case of this design the output relay is only activated if the voltage is permanently below the set voltage value, i.e. longer than the preset period, and if the device is in the operating state. Supply failures, system incidents etc. do not lead to an unintended fault signal. Therefore, the monitoring device is suited e.g. for safety tasks like monitoring of residual voltage etc.


The monitoring device of the type 8539 measures the voltage at the position to be monitored. If the measured voltage is below the selected threshold value, it is registered by the device. If the voltage remains permanently below the threshold value for the duration of the set period, the output relay picks up.

If the voltage exceeds the threshold value again, if the threshold time is adjusted or if the supply voltage is switched off and on again, the output relay drops out immediately and only picks up again when the said conditions are fulfilled again.


Putting into service

The voltage monitoring device of the type 8539 is connected to the voltage source to be measured (e.g. contact line and rail). Thereafter, the operating voltage (supply voltage) is applied. When the measuring voltage selected as the threshold value has been applied to the measuring voltage input, the teach-in procedure (programming) of the device can begin. This procedure can also be performed beforehand in the workshop.

When the button “PROGR USwitch” is actuated, a teach-in procedure is started. During the teach-in the yellow LED lights up. When it goes out, the device works. This teach-in procedure takes less than 30 s. The parameters are stored permanently until the device is re-programmed and also remain stored after a power failure.
The desired response delay can be set with the other button. The response delay can be programmed between 0 s and 9 s.
It is possible to choose between one and two make contacts as the output contact.

Information about further monitoring devices is found in our complete brochure folder.

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