GB433881A - Improvements in control systems for electrically propelled road vehicles - Google Patents

Abstract

433,881. Master control of motors. GENERAL ELECTRIC CO., Ltd., Magnet House, Kingsway, London, and CROFT, E. H., c/o General Electric Co., Witton, Birmingham. Feb. 23, 1934, No. 5996. [Class 38 (iii)] Safety arrangements.-A vehicle motor 7 supplied from an external source 1 is controlled by a master control system including contactors energized from a battery 37, and means are provided, responsive to the voltage applied to the motor, to control certain of the contactors to effect a modification of the motor circuit when the voltage falls to a low or zero value, whereby, when the voltage is restored and the controller 11 is maintained in a running position beyond the first or adjacent running position, the motor current is suitably limited. The circuits of the coils 46W- 50W of armature resistance and field diverter resistance contactors 46-50 include contacts 36 of a relay 36W energized by the supply voltage, and normally open auxiliary contacts 45 of the contactor 46. Thus when the supply fails, contacts 36 open and contactors 46-50 are de-energized to insert all the armature resistance and restore the field strength, the main line contactors 56 being maintained closed through contacts on the controller 11. The normally open auxiliary contacts 45 of the contactor 46 are in parallel with contacts 21, 22, closed only in the second position of the controller 11. Thus the contactor 46 closes in the second position and maintains itself until the controller is returned to its first position, or the voltage relay 36W operates. In the latter case the controller must be returned to its second position before the accelerating contactors can be reclosed. When the contactors 46, 47, and 49 are first closed the circuits of their coils include resistances 52, 54, 55, but subsequently the coils of contactors 47 and 48, are connected in series, and similarly the coils of contactors 49, 50, the resistances 54, 55, being disconnected.