| 摘要 |
PURPOSE:To detect overload of a servo motor highly accurately without building sensors in the motor body by operating control signals in a servo controller. CONSTITUTION:A servo operating circuit 5 in a servo controller 4 receives a position signal pulse 10 of motor from an encoder 2 built in a motor 1 and a position command signal pulse 11 of motor to produce a PWM control signal 12 which is delivered to a drive circuit 3 and an overload operating circuit 6. The overload operating circuit 6 accumulates square of the duty ratio of the control signal 12 minus a constant continuously every predetermined period and delivers an overload detection signal 18 to a servo operating circuit 5 when the accumulated value exceeds a predetermined level. The servo operating circuit 5 brings duty of the PWM signal zero in the control signal and interrupts conduction. This method detects overload of motor highly accurately without requiring any temperature sensor or current sensor. |
