Insulation-resistance degradation detecting device for motors

Abstract

An insulation-resistance degradation detecting device capable of selecting one of a plurality of motors and detecting its insulation-resistance degradation. A power source unit is connected with a plurality of motor drive amplifiers which drive two motors, individually. The motor is selected by selecting means, and a contactor S1 or S2 is turned on. When a smoothing capacitor C of the power source unit reaches a predetermined voltage after an electromagnetic contactor is turned off, contactors SW1 and SW2 are turned on, whereupon one end of the smoothing capacitor C, contactor SW2, resistors R1 and R2, contactor S1 or S2, coil of the motor, insulation resistor Rx of the motor, grounds G2 and G1, contactor SW1, and the other end of the smoothing capacitor C form a closed circuit. The voltage of the smoothing capacitor C is applied to this closed circuit. A potential difference across the detection resistor R1 is obtained and compared with a reference voltage to detect insulation-resistance degradation. The single insulation-resistance degradation detecting device can detect insulation degradation of the plurality of motors, so that a space-saving configuration can be obtained at low cost.

Description

technical field [0001] The present invention relates to an insulation resistance drop detection device for detecting insulation drop of a motor. Background technique [0002] After a motor is used continuously for a long period of time, its insulation performance decreases depending on the working environment. A leakage current caused by a drop in insulation causes an earth leakage breaker to activate, so that a device using a motor will suddenly stop its operation. In this case, it is unknown whether there is a problem with the motor or the drive, and the investigation of the cause of the sudden stop will take a lot of time. Therefore, the equipment using the motor and its production line will stop operating for a long time. [0003] Conventionally, the detection of the insulation drop of the motor is performed based on the aforementioned leakage current detection. However, according to the detection method using the conventional electric leakage detector, the insulation...

AI Technical Summary

Problems solved by technology

If the motor drive equipment includes a plurality of motor drive amplifiers for driving the motor, each amplifier must be provided with a motor insulation resistance drop detection device driven by itself, requiring more space and incurring higher costs

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