GB230934A - Improvements in control apparatus for electrical constant current systems - Google Patents

Abstract

230,934. Austin, G., Macfarlane, J. C., and Macfarlane, W. A. Dec. 22, 1923. Motors, controlling.-Relates to apparatus for governing the speed of electric motors by displacing the brushes relatively to the field poles. A centrifugal governor B acts through an adjustable linkage C, D and a swinging tappet E<2> upon one arm of a short lever F attached to a sleeve H coupled to a brush-shifting frame A<1>. The sleeve H surrounds a shaft G<6> which is operated through gearing by a handle G<1> simultaneously with the actuation of a switch (not shown) for turning on current to the motor. The shaft and the sleeve are resiliently connected by springs G' in compression between projecting arms G<7>, H<1>, and the initial movement imparted to the shaft G<6> thus displaces the brushes from the neutral line in the direction corresponding with the required direction of rotation. The extent of which the brushes are shifted determines the torque of the motor. Simultaneously through a similar resilient connection between two arms K, J, the tappet E<2> is swung to its limiting position facing one arm of the lever F and ready to be rocked back by the action of the governor. In a modification, the connecting linkage between the governor and the brush-shifting gear is arranged to prevent manual movement beyond the neutral position until the speed is below a given limit.