US 7,253,639 B2Granted

Insulation resistance deterioration detection method and insulation resistance deterioration detection device for motor, and motor driver

AssigneeFanuc Corporation

InventorsShinichi Horikoshi, Mamoru Yaeshima, Hiroyasu Sato

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Abstract

The drive of the motor is stopped, the electromagnetic switch contacts are switched OFF, and thereafter the first and second contact points are closed to form a closed circuit of the smoothing capacitor, second contact point, first and second resistors, motor coil, ground 1, ground 2, first contact point, and smoothing capacitor. Charging voltage of the smoothing capacitor is applied to the closed circuit. If an insulation resistance of the motor deteriorates, a current flowing through the closed circuit is increased. The increase of the current is detected by means of the potential difference across the first resistor R1 in the closed circuit, to detect insulation resistance deterioration of the motor.

Claims11

Dependent claims

A method of detecting insulation resistance deterioration for a motor driven by a motor driver which comprises a power supply section in which electric power supplied from an AC power supply through a switch is rectified by a rectifier circuit and smoothed by a capacitor, and a motor driving amplifier in which a DC voltage from the power supply section is converted to an AC voltage to drive the motor, the method comprises:

stopping the operation of the motor by turning the switch OFF, and then connecting one end of the capacitor to ground in conjunction with connecting the other end of the capacitor to a motor coil, after turning the switch OFF;
detecting a current that flows through a closed circuit formed with the capacitor, motor coil, and ground, to detect insulation resistance deterioration of the motor;
and
carrying out said insulation resistance deterioration detection by latching a signal for detecting insulation resistance deterioration by means of a latch circuit when a voltage of a predetermined value is detected by voltage detection means for detecting the potential difference between both ends of said capacitor, after the output of the signal to turn OFF the switch connected to the motor driver.

1 more element

An insulation resistance deterioration detection device for a motor driven by a motor driver which comprises a power supply section in which electric power supplied from an AC power supply through a switch is rectified by a rectifier circuit and smoothed by a capacitor, and a motor driving amplifier in which a DC voltage from the power supply section is converted to an AC voltage to drive the motor, comprising:

a contact point for connecting one end of the capacitor to ground;
means for switching the contact point ON based on a signal sent from the motor driver to turn the switch OFF;
insulation resistance deterioration detection means, connected between the other end of the capacitor and a motor coil, for detecting a current that flows through a closed circuit which is formed with the contact point, capacitor, motor coil, and ground, to detect insulation resistance;
and
voltage detection means for detecting the potential difference between both ends of the capacitor, wherein
said insulation resistance deterioration detection means comprises a latch circuit;
and
the insulation resistance deterioration detection is carried out by latching a signal for detecting insulation resistance deterioration by means of said latch circuit when the voltage detection means detects a voltage of a predetermined value after the output of the signal to turn OFF the switch connected to the motor driver.

5 more elements

Dependencies are inferred from the claim text.