GB376775A - Improvements in and relating to dynamo electric machines - Google Patents

Abstract

376,775. Alternating -current commutator machines. INTERNATIONAL GENERAL ELECTRIC CO., Inc., 120, Broadway, New York, U.S.A.-(Assignees of Allgemeine Elektricitõts-Ges.; 2, Friedrich Karl-Ufer, Berlin.) April 7, 1931, No. 10273. Convention date, April 8, 1930. [Class 35.] The salient pole stator of a three-phase commutator machine excited by alternating currents of different phase has a compensating winding with a coil pitch or mean pitch of 180 electrical degrees and the armature winding has the same or nearly the same pitch, the main pole pitch being 60 electrical degrees, each coil of the exciting winding embracing a main pole without embracing the adjacent commutating poles. Where a three-phase set of brushes is employed, lap windings of 180‹ pitch may be employed for the armature and compensating windings, the exciting winding E and commutating pole winding W being arranged as shown in the Figure where two coils situated 180‹ apart belong to one phase. The number of conductors in series per phase of the compensating winding should equal one-half the number of conductors in series per phase of the armature winding but, where a six-phase sets of brushes is employed these two numbers must be equal. Shunt, main current or separate excitation or a combination of these may be used.