GB383304A - Improvements in and relating to electric motor control systems - Google Patents

Abstract

383,304. Control of several D.C. motors. INTERNATIONAL GENERAL ELECTRIC CO., Inc., 120, Broadway, New York, U.S.A.-(Assignees of Allgemeine Elektricitõts- Ges.; 2, Friedrich Karl Ufer, Berlin.) July 8, 1931, No. 19689. Convention date, July 9, 1930. [Class 38 (iii).] In a system, more particularly for ship propulsion, in which motors M1, M2 are connected in series with one or more generators G, and the speed regulation is effected by motor field or Ward Leonard control, according to whether the motors are running at dissimilar or equal speeds, main controllers 7, 8, associated with the motors regulate the generator fields, and an auxiliary controller 14, coupled with the main controllers through a mechanical or electrical differential 13, regulates the motor fields. When the controllers 7, 8 occupy the same positions, the motors are fully excited, but when they are in dissimilar positions the field of the motor which must have the smaller torque and speed is weakened. The controllers 7, 8 follow guide controllers 3, 4 on the bridge. The controller 14 inserts resistance in the generator fields at the same time as it reduces a motor field, and thereby limits the current. The direction of rotation is determined by motor field reversing contactors under the control of the controllers 3, 4, and the main controllers 7, 8 move in one direction for forward and reverse operation. The generator G- has shunt, series, and separately excited fields differentially arranged, so that when the guide controllers are moved from a forward to a reverse position, the voltage of the generator is temporarily reversed, and then builds up again in the original direction, as the motors speed up in the opposite direction.