GB541976A - Improvements in or relating to electro-magnetic couplings for transmitting mechanical power - Google Patents

Abstract

541,976. Transmitting mechanical power. GENERAL ELECTRIC CO., Ltd., and JAKEMAN, R. G. July 10, 1940, Nos. 11498 and 15658. [Classes 35 and 38 (iv)] An electromagnetic coupling for transmitting mechanical power has a driven member 2 comprising a rotatable element 17 with one or two field windings 3, 6 co-operating with a rotatable element 15 on the driving member 1 having a secondary winding such as a squirrel cape 8. A stator 11 with a polyphase winding 7 co-operates with a D.C. excited field element 4 on the driving member T or a field winding 3 is excited by direct current for forward driving and the same or the other winding 6 is excited by alternating current from the winding 7 to produce an oppositely rotating field for reverse driving without reversal of the drive on the member. When two windings 3, 6 are used they have different pole numbers so as to be naturally non-inductive. The field winding 6 has a greater number of poles than the field winding 3 so that the speed of the reverse rotating field produced exceeds, e.g. as double that of the driving member. Various modifications may be made. The induction motor winding 15 and the windings 3. 6 may be interchanged. The alternator may have more poles than the field winding 6. The alternator may be constituted by a stator enclosing an outer field member on the driving shaft which has also an inner field member co-operating with an induced member on the driven shaft. Application to ship propulsion is referred to.