GB373590A - Improvements in and relating to dynamo electric machines - Google Patents

Abstract

373,590. Alternating current commutator machines. BRITISH THOMSONHOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Hull, J. I. ; 1338, Dean Street, Schenectady, New York, U.S.A.) Nov. 20, 1930, No. 35007. Convention date, Nov. 20, 1929. Void [Published under Sect. 91 of the Acts]. [Class 35.] Converters; commutating windings.-To improve the commutation of machines producing low frequency current, one or more windings in series with the low frequency circuit are arranged approximately at each commutation zone. In the form shown, a two-pole, three-phase 60-5 cycle frequency changer has a rotor primary winding 10, a commutator winding 14 supplying the load lines 19, and a stator winding 18 to make the machine self propelling as a shunt commutator machine, also, in addition, windings 20, 21, 23 on the stator. for improving commutation at each zone. The interpole windings 21 are connected across the brushes and neutralize the induced voltages due to transformer action, and the coils 20, 23 which are in series with the commutator brushes neutralize the voltages due to armature reaction. The windings 20, 23 are arranged so that for each commutation zone there is a winding connected in two of the three phases. To neutralize the torques developed by the interaction of the rotor with the fluxes produced by the commutation improving windings, series windings 24, 25 located on the stator midway between the commutation zones, may be provided. In some cases the windings 23 may be omitted.