System and method for reversing the polarity of permanent magnet DC motors

摘要

A system and method for selecting the rotation direction of permanent magnet DC motors, the system containing a plurality of relays and a control switch which are electrically connected to one another so that an open circuit is present around the motor as soon as the motor is turned off. In one design, the system contains a first relay and a second relay, which each have switching contacts and one coil for applying the voltage to the motor. The system furthermore contains a third relay, which contains switching contacts and a coil for applying a voltage to the motor, a control switch which has a plurality of switch positions for selection of the desired rotation direction of the motor. The control switch, the motor and the relays are electrically connected to one another so that a first control switch position applies a first voltage to the motor, a second control switch position applies a second voltage to the motor, and the second voltage is of the opposite polarity to the first voltage, and a third control switch position produces an open circuit around the motor.