GB202117A - Improvements in and relating to electric ship propulsion systems - Google Patents

Abstract

202,117. British Thomson-Houston Co., Ltd., and Jewitt, D. E. June 21, 1922. Dynamos and motors combined for transmitting power.-In electric power transmission sets for propelling ships, the circuit connecting the motor 1 and the generator 3 contains a braking-resistance 24 arranged to dissipate part of the energy regenerated in the motor when the ship is being brought to rest with fuel supply cut off from the engine. In the arrangement shown, a single handle 5, by means of a hunting switch 13, a pilot motor 15, and a potentiometer resistance switch 16 acting upon the field winding 4 of the engine-driven generator 3, controls the starting, acceleration, stopping, and reversal of the propeller motor 1. A solenoid-actuated switch 25 keeps the resistance 24 short-circuited while the motor is receiving energy from the generator. When the handle is moved back from full ahead, to the stop position shown in full lines, generation, with the resistance 24 still short-circuited, proceeds until the motor 15 has brought the potentiometer switch back to zero, at which point auxiliary contacts on the hunting switch de-energize the solenoid 25 and insert the resistance. If the handle is moved to the astern side, the resistance is automatically short-circuited before the motor accelerates in the reverse direction. An overload relay 28 and a reverse-power overload relay 31 protect the arrangement in the periods of power transmission and regeneration respectively. An adjustable resistance 26 regulates the speed of the pilot motor 15. In a modified arrangement, four generators in circuit with one propelling- motor are controlled in a similar manner by a single handle.