GB651750A - Polyphase alternating current dynamo-electric machines - Google Patents

Abstract

651,750. Dynamo-electric machines. ELLIS, C. E. Feb. 27, 1948, No. 6144. Convention date, Dec. 6, 1945. [Class 35] The stator of a dynamo-electric machine comprises series of skewed rows of pole-faces the poles of each row being energized by alternating current of different phases so as to produce a movement in a conductor depending on the angle of skew. In one form, Fig. 1, described as a squirrel cage induction motor or generator, although it is stated that a wound rotor could be used, the stator 21 is composed of a stack of loose annular laminµ having rows of poles 29 separated by spacers 28. Each pole carries a winding such as 31 which is energized by one phase of a three-phase supply. The poles are skewed from the axial position by means of slats 37 passing through holes in the laminµ and arranged to be moved tantentially by a rotatable ring 40 moved by a worm 42. The result of the skewing is to introduce a peripheral component to the axially moving flux and so cause rotation of the rotor in a direction dependent on the direction of skew. Alternatively the machine can act as a generator whose frequency may be varied independently of the rotor speed. In a modification the skewable poles are interposed between the rotor and a stationary tubular yoke secured inside the frame and energized by annular coils running in grooves around the inner periphery of the yoke. In a further modification, Fig. 6, the rotor consists of a conducting tube divided into axial conductors 68 by slots 69. An outer stator 52 is provided as above, and an inner stator 61, mounted on a fixed tube 59 has teeth corresponding to the rows of poles on the outer stator and is skewed similarly by a slat 64. Both stators are skewed by the rotation of a handle 58 which turns levers 56, 66 fixed to one end of each of the slats. Instead of the mechanical arrangement, the skewing may be done electrically, and Fig. 8 shows the developed diagram of a stator or rotor having a series of rows of poles OV, OW1, OW2, and OW3 with different amounts of skew. These rows are energized at will through a selector switch 75 which may be cam-operated.