GB421595A - Improvements in or relating to electric motors - Google Patents

Abstract

421,595. Alternating-current Induction motors ; condensers. HOWELL ELECTRIC MOTORS CO., Howell, Michigan, U.S.A. June 23, 1933, No. 17988. Convention date, June 25, 1932. [Class 35] [See also Group XXXVI] In an alternating-current motor having a number of stator windings a condenser connected in circuit with one of the windings is arranged around the axis of the rotor. As shown applied to a split-phase motor, the condenser 30 which is preferably of the electrolytic type and capable of withstanding high overloads for short periods, may comprise a single annular member or separate units forming a ring surrounding the motor shaft either within the housing 3 or on the outside of one of the end members 4, 5. The condenser is supported by rubber spacers 31 in such a way that the inner periphery is cooled by natural circulation of air under the action of the rotor. The stator laminations are square with rounded corners so that spaces are left between the straight edges and the cylindrical housing for the passage of conductors connecting the condenser with a centrifugal or electromagnetic switch at the other end of the machine. The centrifugal switch shown comprises two stationary slip rings 22 upon which bears a short-circuiting brush 25 carried by a pivoted arm 26 on the rotor biassed by a spring to bear on the slip rings. At a certain speed, the brush breaks contact with the slip rings thus cutting out the auxiliary stator winding and the series-connected condenser. The condenser is preferably of the type described in Specification 421,628, [Group XXXVI].