OVERCURRENT PROTECTING CIRCUIT FOR DC MOTOR

摘要

PURPOSE:To protect a DC motor against an overcurrent effectively with a simple circuit configuration by providing a current breaker between a power source and a Ward-Leonard circuit and shortcircuitting and breaking the breaker against the power source with the overcurrent detection signal. CONSTITUTION:A current breaker 2 such as a fuse or the like is connected in series between a DC power source 1 and a Ward-Leonard circuit in a circuit for controlling with a chopper a DC motor M by forming a Ward-Leonard circuit in combination of four transistors Q1-Q4 and four diodes D1-D4 in a bridge. Further, there are provided a commutation unit 3 for shortcircuitting the breaker to the power source 1 and a current detector r2. The detection signal from the detector r2 is compared by a comparator 4, and the unit 3 is conducted when excessive current is detected to break the breaker 2.