GB529766A - Improvements in and relating to multi-position electric swtiches, particularly for controlling electric motors - Google Patents

Abstract

529,766. Actuating controllers. BRITISH THOMSON-HOUSTON CO., Ltd., and WISE, W. L. May 22, 1939, No. 30793. Divided out of 515,220. [Class 38 (iii)] A controller for effecting changes in the winding connections of an induction motor to give operation at several speeds comprises a number of switch bases 1 arranged co-axially and located by spacers 7 to form a unitary structure. On the bases are mounted, around the axis, a number of fixed contacts with which movable bridging contacts 6 are arranged to co-operate, these contacts 6 being carried on a shaft 5 passing through the centres of the bases 1. The shaft 5 is rotated to position selectively the bridging and fixed contacts and moved axially to effect engagement between these selected contacts, by means of a handle 11. The handle is free to rotate the shaft in its position O and is operated to its position R to effect operation of the motor at the selected speed. In this position a pin 23 prevents rotation of the shaft. Movement of the handle to a position P against the action of a spring 30 causes reversing contacts 1b to engage contacts on a base 1a to give a plugging operation. Spring coupled arms co-operate with a cam member 29 to hold the shaft 5 in its " off " and " on " positions corresponding to the positions O and R of the handle. A spring biassed roller 20 co-operates with recesses in a member 18 to position the shaft 5 in its several angular positions. The member 18 and its cooperating roller may be formed in a unitary structure with a spring biassed plunger which co-operates with a ball to provide for the axial location of the shaft. A single set of movable contacts may be positioned between two contact bars carrying the fixed contacts to co-operate at will with either.