| 摘要 |
PURPOSE:To protect a device against breakdown by detecting a current to be fed from a power supply through a driver to a motor, comparing the detected current with preset current detection level and overcurrent detection level, and lowering the current detection level and the overcurrent detection level upon detection of overcurrent. CONSTITUTION:Current is fed from a power supply 1 through a driver 2 to the coil 3 of the rotor 4 of a motor. Driving current detected through a current detector 5 is fed to a current limiter 6 and an overcurrent detector 8. The current limiter 6 compares the level of the driving current with a level set by a current detection level setter 7 and when the set level is exceeded, a signal is outputted to limit the current of the driver 2. The overcurrent detector 8 compares the level of the driving current with a level previously set by an overcurrent detection level setter 9 and when the set level is exceeded, a signal is outputted to lower the current detection level and the overcurrent detection level. Consequently, the driver and the coil are protected against breakdown. It is suitable for a business machine. |
