GB575822A - Improvements in and relating to electric brake systems - Google Patents

Abstract

575,822. Brakes. BRITISH THOMSONHOUSTON CO., Ltd. April 13, 1944, No. 6803. Convention date, April 16, 1943. [Class 103 (i)] A brake system comprises an electrically operated brake having a stationary casing with exciting windings 16 and polepieces 15, a rotating electrically - inductive member 20 formed as an impeller for circulating cooling fluid through the brake, the rotating member being driven from the member to be braked, and a heat-exchanger 27 in the circulating system cooled by a fan 35. As shown, the invention is applied to a railway vehicle axle 10 and a pair of eddy current brakes on a common shaft are driven from the axle through gearing 23. The fan 35 is driven by a turbine wheel 36 in the circulation system. Valves 30, closed by springs 31, are opened by the excitation of solenoids 33 preferably connected in shunt across the control resistances 34 and the windings 16. Alternatively, the solenoids may be in series with the windings 16 or may be separately excited. The circulation system is thus closed when the'windings 16 are de-energized, thus avoiding waste of energy by the impeller during normal running. The rotor 20 may include a squirrel-cage winding of radial conductors and circumferentially extending end rings, or it may have a surface of low resistance material. If conductors are provided, they may be made tubular for the passage of coolings fluid. The sustem may be combined with an air-brake system to reduce brake shoe and wheel wear.