GB190906477A - Improvements in and relating to the Rotors of Alternating Current Dynamo Electric Machines, especially applicable to Induction Motors. - Google Patents

Abstract

6477. Lancashire Dynamo and Motor Co., and Stelling, A. R. March 18. Alternating-current induction machines; motors, controlling; brush holders.-In induction motors and the like having slip-rings provided with axially - movable short - circuiting devices, the operating apparatus also moves the brush-gear out of contact with the slip-rings on to adjacent non- rotating brush rests, or the movement of the brushes may make other changes in the connexions. In one arrangement, Fig. 1, in which the slip-rings D are carried outside the outer bearing, the brushes A, which may be of the box type described in Specification 1006/07, are carried on one or more bars B, and are adapted to be moved axially on to fixed rests C having cylindrical surfaces conterminous with those of the sliprings ; the rests are formed on a bracket, the foot of which is bolted to the cover K. The rotor leads e passing through the hollow shaft L are connected to the slip-rings and also to three insulated contact-blocks E carried by bars d connected to the slip-rings. A disk G having short - circuiting spring-like contacts F also rotates with the slip-rings and is movable axially along insulated guidespindles g by means articulated to the brush apparatus, for instance by a handle h, which imparts movement to the bars B by means of a slide H working inside the cover K. The contact blocks E may be between the sliprings and the rotor body. In a modification, the slip-rings are situated between an outer bearing and the rotor body, and the disk G is placed between the slip-rings and the rotor. Fig. 6 shows a modification of this arrangement, in which the bar B is slidable in a bracket b1, b5 carried by a split casting Q which encircles a cylindrical part of the bearing P1. The spring contacts F of the switch are carried on a disk G sliding on the hub l or a shaft L and rotating therewith by means of a feather g5. The disk moves the bar B by means of a pin b2 situated in a peripheral groove g4 therein. The disk is moved axially by means of a bow-lever s encircling it and having two pins s<1> taking into the groove g<4>; the lever s is also keyed to a shaft s<2>, which is rocked by a hand-wheel shaft v, the screw - threaded end of which passes through the jaw t of a lever T fixed to the shaft s2. The brush gear and the disk G may be fixed axially, and the slip-rings and contacts E may be movable. The invention is applicable to cases in which the slip-rings are adapted for changing the connexions, such as for induction motors having different pole windings with corresponding sets of slip-rings, the last set being short-circuited by means similar to that described above.