- OLD SERIES. ASK TO THYTRONIC CUSTOMER SUPPORT FOR AVAILABILITY -

The insulation monitoring relays series DUD are intended to check permanently the good insulation condition of d.c. auxiliary circuits in electric switchgears and substations. They check that the earth leakage resistance from one or the other polarity be higher than the minimum preset value for a good insulation. In case of insulation failure, the faulty polarity is displayed.
The monitored voltage provides the supply to the internal circuits of the relay: therefore it does not require any other auxiliary supply.