GB548588A - Improvements in electro-dynamic power transmitting apparatus - Google Patents

Abstract

548,588. Transmitting mechanical power. BRITISH THOMSON-HOUSTON CO., Ltd., and JEWITT, D. E. Aug. 18, 1941, No. 10490. [Class 38 (iv)] Where two or more prime movers drive a common load, each through an electrodynamic coupling consisting of a field structure associated with an armature, the relationship between the number of poles of one coupling and that on the other or others is such that the load can be driven at a reduced speed by one or more prime movers running at normal speed, the slip energy of the driven couplings being supplied to the load through the couplings of the idle prime mover or prime movers. A slip propulsion system may comprise internal combustion engines or turbines 1, 2 each driving, through a coupling 3, 4 comprising a field structure 7, 8, a polyphase armature 9, 10 and a pole face squirrel cage winding, a common reduction gear 5 and propeller shaft 6. To obtain efficient operation at 80 per cent. propeller speed and the prime mover 2 held stationary the coupling 3 has four times the number of poles of coupling 4. A similar arrangement may be applied to a twin screw drive. A modification is described for a triple screw-drive with three pairs of prime movers, each pair normally driving one screw and wherein, for example, the outer pairs of prime movers may be stopped and their screws driven respectively through their electrodynamic couplings which are supplied in parallel each from one of the couplings of the centre pair.