Apparatus and method for controlling an electric motor

摘要

A feedback control circuit limits current being supplied to an electric drive motor. The motor drives a load cyclically along a path, and the load closes a switch when it passes a predetermined position. This activates a timing circuit which times out after a predetermined delay. If the load does not return to the predetermined position at the end of the prescribed delay time, then an oscillator circuit is triggered into operation to periodically terminate current flow to the motor. This provides cooling periods and enables the motor to exert repeated, temporary high torque efforts to restore normal operation.