Electric drive mechanisms for two coaxial, contra-rotating propellers of a ship or the like

摘要

1,147,504. Electric motor driving arrangements. LICENTIA PATENT-VERWALTUNGS-G.m.b.H. 30 Oct., 1967 [22 Nov., 1966], No. 49149/67. Heading H2A. In a propulsion system for ships &c. using concentric contra-rotating propellers driven by the oppositely rotating members 12, 22 of a synchronous motor 13, the use of slip-rings or rotary transformers for feeding A.C. power to the member 12, is avoided by the use of an induction motor 15 whose rotor 14 feeds slip energy to this member. The induction motor is of much lower pole-number than the synchronous machine, so that it operates at very high slip, and thus feeds most of its energy into the synchronous machine. This slip may be slightly greater or slightly less than unity depending on the rotational senses. The reactive power may be supplied by the machine 13 or from outside. The pole-wheel 22 of the synchronous machine is excited via slip-rings 23. A flywheel may be used to increase the inertia of the inner member to the value of the outer member.