GB230830A - - Google Patents

Abstract

230,830. Deutsche Werke Akt.-Ges. March 12, 1924, [Convention date]. Alternating-current commutator machines; protective or safety devices, auxiliary; brushholders.-Compensated asynchronous motors are provided with protective devices which automatically cut out the motor if the brush-rocker is incorrectly positioned with regard to the direction of rotation. In one arrangement, Fig. 1, an electromagnet f in circuit with the compensating winding n controls the main switch a and is operated when brush-rocker switch blades l wrongly engage either contacts m<1>, m<2> according to the direction of rotation of the rotor, a ring h carrying an insulating plug i and frictionally driven by the rotor shaft in either direction breaking one or other of the contacts k<1>, k<2>. In another arrangement, Fig. 2, a disc o on the main switch release catch c is rotated by current and voltage coils p, q on the main sides of the motor, the coil p being in phase E'and q across phases E<2>, E<3>. No torque is produced on the disc if the brush-rocker is correctly positioned, but if incorrectly positioned a wattless component rotates the disc and releases the catch c.