GB609132A - Improvements in or relating to electric motor control systems - Google Patents

Abstract

609,132. Control of D.C. motors. GENERAL ELECTRIC CO:, Ltd., and DUNHAM, C. R. March 6, 1946, No. 6989. [Class 38 (iii)] Regenerative braking.-A motor control system comprises a D.C. motor arranged to receive power from, or supply regenerated power to, an A.C. circuit which is associated with a constant voltage to constant current transforming circuit and a converter through which the flow of current may be controlled, the converter being arranged to receive power from the A.C. circuit through the transforming circuit, rectify it and supply the D.C. circuit or, alternatively, on receiving regenerated power from the D.C. circuit, invert it and supply A.C. through the transforming circuit to the A.C. system. As shown, the constant voltage A.C. supply 6 is connected across a series resonant circuit comprising an inductance 9 and condenser 10, and across the condenser is connected the primary winding 11 of a transformer 12, in series with an inductance 13 for power factor improvement. The anodes 15 of a bi-phase rectifier are respectively connected to the ends of the secondary winding 14, which has a centre tapping 16 connected to one terminal 17 of the armature of a D.C. motor, the other terminal 19 being connected to a strap connection between the cathodes 18 of the rectifiers. The motor field 3 is separately excited and has a regulator 5, and the armature is connected to drive a load 4 which has an inertia such that regeneration is effected under certain conditions. The rectifiers are grid controlled to ensure alternate operation of the anodes and prevent shortcircuiting of the motor armature. The means 5 controlling the excitation of the motor field 3 may be controlled by a signal dependent on the actual performance of the motor and/or a signal dependent on the desired performance.