GB433370A - Improvements relating to pole changing windings for electric synchronous machines - Google Patents

Abstract

433,370. Controlling dynamo-electric machines ; windings for dynamo-electric machines. SIEMENS - SCHUCKERTWERKE AKT.-GES., Siemensstadt, Berlin. Jan. 9, 1934, Nos. 847 and 848. Convention dates, Jan. 9, 1933. [Class 35] A pole-changing stator winding for a synchronous machine is made by winding the stator to give a number of poles intermediate between those required, dividing this winding in each phase into a number of sections equal to the phase number or a multiple thereof, and furnishing these sections with terminals so that they can be recombined to give the pole munbers required. A 36-slot winding for five poles, divided into in each phase into three sections and recombined to give four or six poles and a 27-slot winding with similar divisions are described. To allow of corresponding charges in the rotor winding it is made in two groups of conductors so arranged that by reversing one of them the number of poles is changed. The Figure shows such a construction to give 10 or 12 poles. In the two uppermost lines the full and dotted portions represent the portions of the circumference which have a different polarity in the two cases respectively, so that by reversing the portions which differ in the two lines, indicated in the third, the required change is effected. This can be done by dividing the winding into two portions distinguished by full and dotted lines in the fourth line of the figure and reversing the portion indicated by dotted lines. By forming the winding in two or more layers and slightly displacing one layer relatively to the other harmonics can be suppressed.