METHOD OF CHECKING OF INSULATION RESISTANCE OF SINGLE-PHASE ELECTRIC MAINS AND DEVICE INTENDED FOR ITS REALIZATION Russian patent published in 1998 - IPC

FIELD: electric engineering. SUBSTANCE: method is used for checking of single-phase low-voltage electric mains under conditions where dangerously explosive concentrations of gas or dust may be formed. Checking device includes assembly designed to detect moment at which mains voltage sinusoid passes through zero. It also has check voltage switch, biasing assembly, diode, and assembly of mains capacitance levelling with respect to ground. In this case, input of assembly designed to detect moment at which mains voltage sinusoid passes through zero is connected to sinusoidal voltage source, and its output is connected to input of check voltage switch. First lead of switch output is connected through sensitive member input and first lead of biasing assembly to input of assembly which introduces check voltage into mains. Second lead of check voltage switch and second lead of biasing assembly are connected to second lead of check voltage source. Diode is connected in parallel to check voltage source, and mains capacitance levelling assembly is connected to mains conductors and to ground. EFFECT: high accuracy of insulation resistance checking. 2 cl, 1 tbl, 1 dwg