GB1213584A - Improvements in or relating to electric motors and brakes - Google Patents

Abstract

1,213,584. Electric motors having brakes. MOTEURS LEROY. 4 Jan., 1968 [18 Jan., 1967], No. 660/68. Heading H2A. In a motor having a spring-loaded brake plate 15 slidable on the rotor shaft 11 and which, on energization of the motor, is withdrawn from engagement with a stationary friction lining 14 by stator flux diverted through an end ring 22 on the rotor, the ring 22 splits the flux so that 80 to 90% of the flux passes through a series of short-circuited windings W and is displaced in phase relative to the remainder whereby the hole ring is not demagnetized as the flux passes through zero and chattering of the plate 15 is prevented, particularly with a single phase supply. As shown, ring.22 forms part of a squirrel cage rotor 12 and initially has radial slots and annular grooves on opposite faces. Non-magnetic metal such as aluminium, is injected into said slots and grooves and into the rotor slots to form the squirrel cage bars 41, Fig. 7, end rings 42, 43, an outer end ring 46 of smaller diameter, and radial partitions 45. Rings 43, 46 and partitions 45 form the shortcircuited windings W and the parts F 1 , F 2 of the flux F pass through the parts of the end ring 22, not shown in Fig. 7, on either side of the smaller diameter ring 46.