GB445694A - Improvements relating to control apparatus for alternating current commutator motors - Google Patents

Abstract

445,694. Master control of motors; actuating controllers. BENNITT, W. B., Ivybank, Moss Lane, Ashton-on-Mersey, and ASSOCIATED ELECTRICAL INDUSTRIES, Ltd., Crown House, Aldwych, London. Oct. 9, 1934, No. 28932. [Class 38 (iii)] Control apparatus for an alternating-current commutator motor 1 speed - controlled by movement of its brushes, comprises electrically operated clutch means 12, 13, between the brush-shifting gear 4 and a member 6 continuously rotated at least while the main motor is in operation, a controller 26 whereby the motor is energized and the clutch means selectively operated to cause the brushes to be moved to increase or decrease the speed or to be left in an intermediate position, and additional means 22, which are rendered effective only upon de-energization of the main motor, to bias the brushes to the minimum speed position. Movement of the controller to position I in the hoisting direction connects the main motor to the supply for hoisting operation and, if the brushes are not in the minimum speed position and limit switches 36, 37, are closed, a clutch coil 17 is energized to couple the brush-moving gear to a bevel pinion 8 and cause return of the gear to the minimum speed position. Movement of the controller to the position III in the hoisting direction causes energization of a clutch coil 16 so that the brush-moving gear is coupled to a bevel pinion 10 and moved to the full speed position, whereupon the limit switches 38, 39, are opened, the brushes may be held in an intermediate position by moving the controller to position II. Similar control is exerted for the lowering operation. The brush gear operating shaft 5 is provided with a crank 18 engaging a weighted crank 21 mounted by "free-wheel" mechanism 20 on a sleeve 19 freely mounted on the shaft 5. This sleeve is held fast by a brake 23 applied by a coil 24 for all on positions of the controller 26. During movements of the brush gear in a speed increasing direction the crank 21 is operated, the " free-wheel " mechanism permitting this operation but preventing return movement when the brushes move in a speedreducing direction. When the controller 26 is moved to its " off " position, the coil 24 is de-energized to release the crank 21 which falls under the influence of the weight 22 and returns the brush gear to the minimum speed position. The member 6 may be driven by a pilot motor which may be reversible, or, as shown, from the shaft of the motor 1. Specification 210,236, [Class 38 (iii)], is referred to.