DEVICE FOR MEASURING AND CHECKING ISOLATION RESISTANCE OF ELECTRIC CIRCUIT Russian patent published in 1995 - IPC

FIELD: electric engineering. SUBSTANCE: device has diode bridge 1 brought into power circuit of the device, current transducer 2 - generator is made as current transducer made on the base of unit with negative differential resistance in form of a megatron -, isolation transformer 4 start-controlling equipment 5. Principle of operation of generator on the base of megatron is the following. At E_в passing through restricting resistor R, the charge is accumulated in capacitor C and voltage increases. When the voltage achieves breakdown voltage of megatron, pulse is generated at output of the circuit. Pulse frequency is determined by speed of charge of the capacitor. Speed of charge is determined by nominal value of restricting resistor: the higher is nominal value of resistor R, the higher is generation frequency. If charge leakage of capacitor is available at the circuit, then at some critical value of resistor R the generation terminates as voltage at capacitor C does not achieve breakdown level of megatron. If isolation resistance of electrical installation is used as current-limiting resistor, then specific generation frequency f_g= F(R_is) will correspond to any value of isolation resistance. Isolation resistance of electrical installation may be measured in electrical circuit by measuring this frequency or by converting the frequency into other physical values. EFFECT: improved reliability of checking; reduced energy consumption. 1 dwg