Electromagnetic contactor with control circuit for providing acceleration, coast and grab functions

Abstract From the Canadian patent

An electromagnetic contactor or controller is taught in which the voltage which is impressed across the electromagnetic armature accelerating coil is compared by a microprocess against a menu of memory stored voltages with related delay angles. The delay angles are utilized to alter the conduction interval of a triac or similar gated device which is connected in series circuit relationship with the coil in question. During an ACCELERATION interval a number of consecutive full-wave rectified half-cycles of voltage pulses are phase angle or delay angle controlled so that the amount of energy provided to the moving armature of the contactor is approximately sufficient to cause the armature to …