The Siemens Insulation monitoring relays are used for monitoring the insulation resistance between ungrounded 1- or 3-phase AC supplies and a protective conductor. It measure insulation resistances between system cables and system ground. If the value falls below the threshold value, the output relays are switched to fault status.
Device for AC and DC systems Wide control supply voltage range Frequency range 15 to 400 Hz Monitoring of broken conductors
