GB429181A - Improvements in or relating to electric motor control systems - Google Patents

Abstract

429,181. Field control of D.C. motors. GENERAL ELECTRIC CO., Ltd., and COLLETT, E. P., Magnet House, Kingsway, London. Nov. 21, 1933, No. 32491. [Class 38 (iii)] When a motor is first connected to its supply, its field excitation is reduced by the omission of the excitation of a field winding, or by varying the field ampere turns pro. duced by the current flowing in a field circuit under the control of a controller segment, the field excitation being subsequently increased before all the series starting resistances are cut out. At the first position of the controller a motor 1 is connected to the line with armature resistance 8 in circuit, and a diverter resistance 14 across the series field 13. At the next position the contactor 15 is opened and the motor has full field. Thereafter the resistance 8 is cut out in steps by contactors 9, 10, 11, 12, and the diverter resistance again connected and reduced in steps by contactors 15, 16, 17. When the controller is moved back the contactor 15 may be prevented from closing on the first step so that a low speed running position is obtained. When a compound motor is employed the reduction of the field when the motor is first connected may be effected by cutting out the shunt field. With seriesparallel control the field may be similarly controlled for the first parallel step.