Abstract: A variable speed eddy current electric motor includes a zero-torque regulating circuit that senses and responds to the current flowing through an eddy current motor field coil. As the magnitude of the field coil's current is changed by the eddy current motor's speed control circuit, the operating method of the zero-torque regulating circuit supplies varying amounts of current to flow through the field coil in a direction opposite to that of the current applied thereto by the speed control circuit. Thus, when the eddy current motor's speed control circuit no longer causes any current to flow through the field coil, the current supplied to the field coil by the zero-torque regulating circuit produces a magnetic filed that removes all torque from the eddy current motor's output shaft.

Abstract: A testing system is removably connected to a control of an elevator system and selectively operated to perform a plurality of testing sequences. The testing system is removably connected with a closed loop elevator control and selectively and independently provides a number of artificial control signals characteristic of an operating condition for controlling the operation of the elevator system under test. The testing system may be used in a testing sequence with elevator systems employing gated rectifying circuits to accurately monitor gate pulses and other operating functions therein.