DEVICE TO MONITOR RESISTANCE OF INSULATION OF AC ELECTRIC CIRCUIT Russian patent published in 2014 - IPC G01R27/00 

FIELD: measurement equipment.

SUBSTANCE: device to monitor resistance of insulation of an AC electric circuit comprises a low pass filter, the inlet of which is connected to the monitored circuit, a source of reference voltage, an indicator and comparators of emergency and warning alarms. The device is additionally equipped with a converter of resistance into voltage, a differential amplifier, a unit of differentiation and the third comparator, besides, the source of reference voltage is connected to the first inlet of the differential amplifier and the inlet of the converter of resistance into voltage, one outlet of which is connected to the inlet of the low pass filter, and the other one - with the inlet of the differentiation unit and the second inlet of the differential amplifier, the outlet of which is connected with the indicator and with the first inlets of comparators of emergency and warning alarms, to the second inlets - strobing inlets of which the outlet of the differentiation unit is connected via the third comparator.

EFFECT: reduced impact of a monitoring device at a network, increased accuracy and resolving capacity in entire range of insulation resistance variation, simplified calculation of insulation resistance value, prevention of false actuations.

2 cl, 2 dwg