GB413641A - Improvements relating to the control of direct current electric motors - Google Patents

Abstract

413,641. Master control of motors; drum controllers. FERGUSON, A. D., Ardriac, Ashton Lane, Ashton-on-Mersey, and ASSOCIATED ELECTRICAL INDUSTRIES, Ltd., Crown House, Aldwych, London. Jan. 16, 1933, No. 1420. [Class 38 (iii).] A remote control system for a number of motors includes a drum switch having pairs of operative positions corresponding to the inclusion of all motors or groups of motors in circuit, or the exclusion of a selected motor or group of motors, the drum switch being operated under the control of a master controller from one operative position to another operative position, for each pair to change the motor connections other from forward to reverse, or from power to brake operation. Motors 1, 2, Fig. 1, are under the control of a power-brake switch having positions P, B, and a combined reversing and cut-out drum switch RC. With the power-brake switch in power position P, and the switch RC in position R or F corresponding to " Both in," both motors are connected to run in a forward or reverse direction, subject to resistance control r, and series-parallel control S, M, G. When the switch RC is in position R or F corresponding to either " No. 1 Out" or " No. 2 Out," one of the motors only is connected for forward or reverse operation. Movement of the power-brake switch to position B connects the motor or motors for rheostatic braking. The reversing switch may have merely forward and reverse positions, the power-brake switch being provided with three sets each of two operative positions corresponding to driving or braking operation with both motors or a selected one in circuit. The combined cut-out and reversing switch or cut-out and power-brake switch consists of a contact carrying drum 20, Fig. 3, mounted on a shaft 21 which carries a loose pinion 29 gearing with a rack reciprocated by pneumatic means. A hand-wheel 30, having a boss 32, is arranged to slide but not rotate on the shaft 21, and is biassed by a spring 31 to a position in which projections 33 on the face of the pinion 29 engage recesses in the face of the bars 32. Thus the drum may be moved to any of three pairs of positions, the particular pair being selected by withdrawing the hand-wheel 30, rotating the shaft according to a pointer 35 co-operating with a scale 34, and releasing the handle to re-engage the pinion 29. Alternatively the drum 20 may be mounted on a sleeve rotatable on the operating shaft which is provided with a spring-controlled bolt engaging any one of several holes in the sleeve. Specification 413,642 is referred to.