GB1151467A - An Electric Motor and Associated Equipment for Rotating a Body - Google Patents

Abstract

1,151,467. Electric motor driving arrangements. SIEMENS A.G. 4 Dec., 1967 [2 Dec., 1966], No. 55137/67. Heading H2A. An induction motor operating on either two poles or an alternative higher pole-number (four or six poles) for automatic washing machines, has separate windings for the two pole numbers, the higher having an auxiliary capacitor winding for starting at the lower speed and the lower having a main winding only, centrifugal means acting to interpose reduction gearing when the motor is operating at its higher pole number, and an automatic clutch coupling it direct when the motor is running fast. By this means a low tub speed is obtained for washing and a high speed for drying. The clutch permits some slip to avoid stalling the motor when the gearing is suddenly replaced by a direct drive. To initiate the disengagement of the reduction gearing, the high-speed winding is momentarily energized while the motor is still running on the higher pole-number. This forces the speed up above the no-load lower speed, and the clutch automatically operates to disengage the gearing and couple the drum directly to the motor. The low speed winding is preferably symmetrical so that it may be reversed by changing over the capacitor. The high-speed winding is sinusoidally graded and has a band-width of 2/ 3 pole-pitch. The lamination shown has 24 slots of which two groups N are larger, the lamination being elongated to accommodate them. The low-speed winding lies in all the slots equally, but the high-speed winding is confined to the 16 large slots N. Stack-welding recesses S are provided.