Littelfuse PGR-3200, Insulation Monitor

The PGR-3200 series insulation monitor operates on ungrounded ac systems. This unit detects ground faults by continuously monitoring the insulation integrity of ungrounded electrical systems. It monitors the insulation for damage and assists with predictive maintenance and troubleshooting of developing ground-faults by providing a warning or an alarm. The three levels of detection are: a 50 kΩ warning with an LED and output contact indication; a 30 kΩ warning with LED indication; and a 10 kΩ alarm with LED and output contact indication. An analog output is provided for predictive maintenance trending. The PGR-3200 operates on one- or three-phase ungrounded systems up to 6 kV. This unit can also be used on a grounded system to monitor the insulation for damage while the power system is de-energized. The mode-of-operation terminals (27-28) are connected to the circuit breaker or contactor auxiliary contacts to toggle the relay off when the contactor or breaker is closed.