GB425894A - Improvements in regenerative electric motor control systems - Google Patents

Abstract

425,894. Master control of D.C. motors. GENERAL ELECTRIC CO., Ltd., Magnet House, Kingsway, London, and CROFT, E. H., c/o General Electric Co., Witton, Birmingham. July 20, 1933, No. 20493. [Class 38 (iii)] Regenerative braking; field control.-In a control system for a compound - wound traction motor 1 in which forward movement of a master controller 26 effects acceleration of the motor solely by means of armature and field resistance control and in which backward movement of the controller from its full speed position effects strengthening of the shunt field excitation 3 for regenerative braking, the controller is provided with contacts 41, 42 bridged only during the backward movement to effect an increase of shunt excitation such that for various positions of the controller the shunt excitation is then greater than that obtained in the said positions as the result of forward movement, whereby a strong field is obtained notwithstanding the opposing effect of the series winding 2. The controller contacts 41, 42 cut-out a step of the shunt field resistance 13 which is inserted for all positions during forward movement of the controller. This additional step of shunt field resistance may be cut-out in steps governed either by the value of the regenerated current or by the degree of backward movement of the controller. In a modification, the additional increase of shunt excitation during regeneration is effected by a reverse-current relay.