GB643753A - A commutator winding for multi-phase commutator machines - Google Patents

Abstract

643,753. Winding layouts for dynamo. electric machines. MORAVIAN ELECTRICAL ENGINEERING WORKS, NATIONAL CORPORATION, and KILMA, V. Dec. 5, 1947, No. 32155. Convention date, Dec. 5, 1946. [Class 35] A commutator winding for a polyphase A.C. machine is fed by brushes at 2m points per pole pair where the number of slots is 4m per pole pair, m being an integer greater than two (usually three), and the feeding points are unsymmetrically spaced from each other because out of 4m regularly distributed feeding points half are omitted, i.e. only one of each pair of diametrically arranged feeding points is fed. The number of feeding points can be further increased if the winding is subdivided into two parallel windings, e.g. one a lap winding and the other a wave winding, with the same number of parallel branches each connected to the segments and having a pitch which is shortened or extended by an odd number of slots so that the conductors of the two coils lie in four slots. As shown, the regularly distributed feeding points 1, 2... 12, are only fed at points 1, 2, 5, 6, 9, 10 through a secondary winding X, Y, Z. The coils b, c (lap) and d, a (wave) are short pitched by one slot but modifications are shown in which they are shortpitched by three or five slots. If a multiple parallel winding is used an additional auxiliary wave or lap winding having a pitch of about <SP>1</SP>/ 3 pole-pitch is also wound into the slots and connected to the commutator segments. It is stated that half of the armature coils (laps and waves alternately), may be omitted, so that there are only two conductors attached to each segment, without impairing the function of the machine. The winding may be energized by two sets of brushes as above, the sets being joined through stator windings so that speed regulation may be obtained by shifting the brushes so as to alter their relative positions on the commutator: