GB740683A - Improvements in and relating to control systems for internal combustion engine-electric power plant - Google Patents

Abstract

740,683. Transmitting mechanical power. BRUSH ELECTRICAL ENGINEERING CO., Ltd. May 22, 1952 [March 30, 1951], No. 7374/51. Class 38 (4). In a control system for maintaining constant engine speed and loading in internal-combustion engine-electric power plant, such as used for vehicle propulsion, by automatic control of the regulating rheostat 52 in the field circuit G of the main generator 53, the rheostat is operated by a reversible electric servomotor 43 under the control of a change-over switch 41 having an intermediate " off " position, the switch being operated by a fluid servomotor 36 having a control valve 14 responsive to deviations from a given setting of an engine-driven governor 1. A sleeve valve 22 co-operates with valve 14 and is moved by a cam 20 in accordance with fluidpressure loading applied to the governor, whereby the engine may be controlled to run at any desired speed. The automatic control of the generator is temporarily suspended when the generator attains a voltage at which changeover from series-parallel to full parallel connection of the traction motors is desirable. At this voltage, a relay RL operates to de-energize a contactor TC1 which, at its main contacts, disconnects the slider 51 of rheostat 52 and, at contact TCla completes an energizing circuit for a contactor TC2 which closes its contacts to short-circuit a portion of the rheostat. The resulting generator excitation is such that about 5 per cent overload occurs as parallelling proceeds, so that motor 43 operates the moving element of the rheostat in the " lower voltage " direction, this element eventually operating a contact SE (when adjacent tapping j) and restoring automatic load control by completing a circuit for re-energizing contactor TC1 previously prepared by contact P2c which closed when parallelling was completed. In a modified system, which does not rely on engine overload to retract the moving element of the rheostat, a relay energized in shunt with contactor coil TC2, when parallel connection of the traction motors is complete, completes an auxiliary circuit for energizing motor 43 in the " lower voltage " direction.