GB381957A - Improvements in electric motors - Google Patents

Abstract

381,957. Induction motors. LANCASHIRE DYNAMO & CRYPTO, Ltd., (formerly LANCASHIRE DYNAMO & MOTOR CO., Ltd.), Trafford Park, Manchester, and HOWARD, J. W., 21, Sandy Lane, Stretford, near Manchester. July 11, 1931, No. 19967. [Class 35.] Conductors.-At one or both ends of the squirrel-cage rotor, and between the end of the core and the end connections there is provided a magnetic mass mounted on the shaft and having holes for the passage of the rotor bars. In the form shown, the bars have end rings J3, J4 and pass through holes m4 in the iron disc M1, the spider portion m2 of which is keyed to the shaft. Except in small machines these holes are larger than the bars and only a group of bars which are situated at points of approximately equal potential are in metallic contact, this contact being effected by metallic sleeves K which may extend to the end ring. Insulating sleeves may be fitted on the other bars and the disc M1 may have radial saw-cuts extending from its periphery to the holes m4 or to an intermediate point, but these would not usually be made for holes having a sleeve K. Where the rotor bars are skewed, the holes in the disc M1 may be skewed or the end parts of the bars may be straightened. Intermediate spiders P .. S having arms angularly displaced may be provided to support the bars and each may have holes traversed only by a group of equipotential conductors, there being one arm per pair of poles. The disc M1 may be fitted with fans T2, T3. The rotor bars may only be in contact with the core at collar portions h2, Fig. 8, which are axially displaced in various bars.