GB606385A - Improvements in and relating to dynamo electric machines - Google Patents

Abstract

606,385. A.C. commutator machines. BRITISH THOMSON-HOUSTON CO., Ltd., and MAGGS, A. H. Jan. 14, 1946, No. 1238. [Class 35] An A.C. motor or generator has a polyphase stator winding acting as an armature winding and a commutated winding on the rotor acting as a compensating winding effectively in series with the armature winding and inductance is connected to the windings to enable shunt exciting currents to flow in the windings with predominant effect in the compensating winding in lagging quadrature with the E.M.F.'s generated in the stator winding by the rotating flux, the compensating winding serving also as an exciting winding. As shown, each unsaturated choke 23, 24, 25 is connected between an auxiliary brush 26, 27, 28 and a mains terminal 8, 9, 10 of the armature winding 5, 6, 7 connected to the compensating winding 1 through main brushes 2, 3, 4, but alternatively each choke may be connected between tappings on each of the two adjacent armature phases. The compensating winding may have tappings brought out to a slip-ring when a neutral point for earthing is required, or the armature windings may be connected to the brushes indirectly by means of a transformer with a star-wound winding connected to the armature windings to give the neutral point, the other winding of the transformer being delta connected across the brushes. There may be a squirrel cage damping winding in the same slots as the compensating winding. According to the Provisional Specification, condensers may be across the phases of the armature winding.