REVERSING DEVICE AND REVERSING METHOD OF PERMANENT MAGNET DC MOTOR

摘要

PURPOSE: To prevent a current from being applied to a contact between a brush and a relay, when the driving of a DC motor having a permanent magnet is discontinued. ;CONSTITUTION: If a control switch 44 is turned to a clockwise switching position (CW), a bipolar double-throw relay is excited, and normally-closed contacts 50 and 50' and normally-opened contacts 52 and 52' are switched and a current iCW is applied to turn a motor 42 clockwise. If the control switch 44 is turned to a counterclockwise switching position (CCW), an unipolar single-throw relay 48 is excited and a normally-opened contact 60 is closed and a current iCCW is applied. If the control switch 44 is turned to an off position from the clockwise switching position (CW) or the counterclockwise switching position (CCW), since the normally-closed contact 50' is connected to the normally-opened contact 60 and the normally-closed contact 50 is connected to the normally-opened contact 52', a route through which a current which is generated by the inertia of the motor 42 flows is cut off. With this constitution, the operating lives of brushes 64 and 66 and a relay 48 are prolonged.;COPYRIGHT: (C)1995,JPO