GB189908482A - Improvements in Alternating Current Motors. - Google Patents

Abstract

8482. DÚri, M. April 22. Motors, alternating-current.-Comprises improvements on the invention described in Specification No. 2426, A.D. 1898, for facilitating the starting of monophase or polyphase alternating current induction motors, according to which the field magnet was arranged to produce a certain number of poles at starting and a multiple or aliquot part of that number during the working period. According to the present invention, there may be any desired proportion between the two numbers of poles, such as 4 : 6 or 6 : 8. Fig. 1<a> shows diagrammatically the arrangement of a single-phase motor, working with 4 and 6 poles during the two periods. Diametrically-opposite armature coils S<1> S', S<2> S', &c. are connected together and to the segments of a commutator by the conductors c, and the commutator brushes are connected together through resistances r. In a modification, the resistances are interposed between the armature coils and the commutator segments. Fig. 3<a> shows the means adopted for varying the number of field poles produced by a ring winding. The winding has twelve consecutively-numbered coils, and of these the coils 1, 2, 3, 4, 6, and 11 are connected with the terminale z<1> and z<2>, so that currents always pass through them in the same direction, while the coils 5,7,8,9,10, and 12 are connected therewith through a switch v, so that the direction of the currents passing through them can be reversed at will. The connections for a drum-wound magnet are also described.