US 7,064,516 B2 · Motor driver

Abstract

While the motor drive amplifier is not operating, electromagnetic switch contacts are held closed for a predetermined period of time, three-phase power is rectified by a rectifier circuit and a smoothing capacitor is charged. Then, the smoothing capacitor is discharged through a discharging resistor and, when a predetermined voltage is reached, a contact is closed, with the result that a closed circuit is formed by the smoothing capacitor, a detection resistor, a motor coil, motor insulation resistance, and ground. A voltage generating across the detection resistor due to leakage current is detected and compared with a reference value. If the detected voltage exceeds the reference value, an insulation degradation signal is delivered.

Claims9

Dependent claims

A motor driver, comprising:

a power supply section in which the power supplied from an AC power supply through a switch is rectified by a rectifier circuit and smoothed by a capacitor;
a motor drive amplifier in which a DC voltage from said power supply section is inverted to an AC voltage to drive a motor;
a detection resistor connected in series with a motor coil;
voltage applying means for connecting said rectifier circuit to ground, after operating said switch for a certain period of time to store energy in said capacitor, and then applying energy stored in said capacitor through said detection resistor to the motor;
and
a voltage detection circuit detecting a potential difference across said detection resistor.

3 more elements

Dependencies are inferred from the claim text.

Motor driver

Life of this patent

Motor driver

Life of this patent

Abstract

Claims9