GB428957A - Improvements in and relating to electric motors - Google Patents

Abstract

428,957. Alternating-current motors. BRITISH THOMSON - HOUSTON CO., Ltd., Crown House, Aldwych, London.- (Assignees of Allgemeine Elektricitõts-Ges. ; 2, Friedrich Karl-Ufer, Berlin) Jan. 29, 1934, No. 2982. Convention date, Jan. 27, 1933. [Class 35] Motors with unwound iron armatures.-A singlephase synchronous motor has on the stator auxiliary polepieces further from the main polepieces of similar polarity than from the main polepieces of opposite polarity, and this shorter spacing is equal or proportional to the rotor pole pitch. In the form shown, the plate 8 carries main poles 81 and shaded poles 82 which are interleaved with corresponding poles 71, 72 respectively on the edge of the cylinder 7 containing the winding 5 and core 9. The torque may be increased by the provision of additional poles 73, 83 on the two stator members. The plate 8 may be replaced by a second " potshaped " member, the polepiece arrangement being the same. The rotor comprises a Ferraris disc 10 with a toothed ring 11 of magnetic material and may have a yoke ring 12. Some rotor teeth may be omitted, the pitch being kept the same. In a modified form having radially extending rotor poles, the winding is located between two of the stator poles and the rotor may have a squirrel cage winding. The polarity of the rotor teeth does not change. Specification 428,958 is referred to.