| 摘要 |
PURPOSE:To eliminate vibration or noise due to unstable speed control of motor by interrupting power supply to each drive coil for a quite low speed command signal thereby interrupting driving of motor. CONSTITUTION:Speed control of a motor is carried out according to a motor speed command signal fed from a speed command means 4, but stable speed control becomes difficult as the speed command signal shifts to a low speed command signal. When a speed command signal having a level lower than a predetermined level is provided from the speed command means 4, an ultra- low speed command protective means 7 detects the fact and provides a command signal for turning the driving transistors 11-16 OFF to a power control circuit 24. In other words, the power control circuit 24 functions to interrupt power supply to driving coils 1-3. |
