GB494363A - Improvements in or relating to means for indicating failure of the electric supply in regenerative electric motor control systems - Google Patents

Abstract

494,363. Control of motors. GENERAL ELECTRIC CO., Ltd., and TURRALL, J. C. June 25, 1937, No. 17733. [Class 38 (iii)] For indicating failure of the supply in a regenerativ e motor control system, a lamp 14 or other indicator is connected to the supply in parallel with the motor 1, and a relay having a coil 18 energized in accordance with the motor armature current prevents energization of the indicator circuit by the voltage generated by the motor when the supply fails during regeneration. The contacts 17 of the relay are in parallel with contacts 15, 16 connected in series, the contacts 15 being normally closed auxiliary contacts of a line switch LP, and the contacts 16 normally closed auxiliary contacts of a contactor 13 whereby accelerating resistance 12 is shortcircuited. The motor 1 operates a trolley bus and during regenerative or motoring operation, the energization of the coil 18 closes the contacts 17 and the lamps 14 are energized. During regeneration, if the supply fails due to the trolleys leaving the conductors, the energization of the coil 18 falls and the lamps 14 are extinguished. During coasting with the motor disconnected, the lamp circuit is completed through the contacts 15, 16. If the contactor 13 is connected across the resistance 12 only, the contacts 16 may be dispensed with. The Provisional Specification describes an arrangement in which the armature current relay has two sets of contacts.