GB239830A - Improvements in and relating to electric control systems - Google Patents

Abstract

239,830. British Thomson-Houston Co., Ltd., (Assignees of Winter, F. H.). Sept. 15, 1924, [Convention date]. Selective distant control systems.-Selective distant control of a number of electric circuits is effected by unbalancing a relay which sets in action a travelling contact device arranged to restore the balance of the relay and thus bring the contact device to rest when the selected position is reached. In the system shown in the Figure a master rheostat 5 when set in a selected position puts a corresponding amount of resistance into the circuit of one of the relay balancing magnets 2, which closes the relay contacts 24, 25 and thus starts a distant motor 28 through reversing switches 59, 60 and a brake-releasing switch 40. The motor, through worm and screw gearing, drives the travelling contact member 22 over the successive contacts of the circuits to be selected 43 - - 51 and simultaneously puts sections of a resistance 6 into the circuit of the relay balancing magnet 3 which reopens the contacts 24, 25 when the selected position is reached. To make sure that the travelling member 22 takes up a position in the middle of the selected contact, hold-circuits for the magnets of the switches 59, 60 are kept alive by intermediate contacts 98 - - 106 for the necessary short interval after balance has been attained. Specification 26295/04, [Class 38, Electricity, Regulating &c.] is referred to.