GB194095A - Improvements relating to electric power drives - Google Patents

Abstract

194,095. Field, A. B., and Metropolitan- Vickers Electrical Co., Ltd. Feb. 1, 1922. Dynamos and motors combined for transmitting powers.-An electric power transmission system, particularly applicable to ship propulsion, comprises a two-phase motor supplied from two twophase generators one of which supplies energy to one phase winding and the other supplies energy to the other phase winding of the motor, reversal of direction of rotation of the motor being obtained by reversing the excitation of one of the generators. Asynchronous or synchronous motors, or machines adapted to run either as asynchronous or synchronous motors may be employed. The system may comprise several motors and generators. Two two-phase generators 1, 2, Fig. 1, are mounted on a prime-mover shaft 3 and are connected to two two-phase induction motors 17, 18 on a propeller shaft 16. The phase winding 19 of the motor 17 is connected to the phase winding 4 of the generator 1, while the phase winding 20 of the motor 17 is connected to the phase winding 7 of the generator 2. The phase winding 21 of the motor 18 is connected to the phase winding 6 of the generator 2, while the phase winding 22 of the motor 18 is connected to the phase winding 5 of the generator 1. The field windings 8, 9 of the generators 1, 2 are excited by a machine 10 and the circuit of the field winding 9 is provided with a reversing switch 11. To reverse the direction of rotation of the shaft 16 the excitation of the generators 1, 2 is reduced by reducing the excitation of the machine 10, the field 9 of the generator 2 is reversed after which the excitation of the generators is increased to normal. The motors 17, 18 may be mounted on separate shafts. When synchronous motors are employed a reversing switch, connected mechanically to the reversing switch of the generator, is placed in the field circuit of one of the motors. In the arrangement shown in Fig. 3 the two-phase generators 47 and 48 are connected to the motors 43 and 45. and the two-phase generators 49 and 50 are connected to the motors 44 and 46. The motors being on separate shafts it will be unnecessary to reverse the fields of any of the motors if synchronous motors are employed. In a modification the four motors shown in Fig. 3 may be arranged on two shafts, two on each shaft, and the four generators mounted on a single shaft. Further two generators may be combined in a single machine and the fields of the separate generators are reversed to reverse the directions of rotation of the propeller shafts. In the modification shown in Fig. 5 one phase of each motor 58, 59 on the shaft 55 is supplied from a generator 65, one phase of each motor 60, 61 on the shaft 56 is supplied from a generator 66, one phase of each motor 62, 63 on the shaft 57 is supplied fom a generator 67, and the other phases of all the motors are supplied from a generator 64. To reverse the direction of rotation of the shafts 55, 56 and 57 the field of the generator 64 is reversed, while any one shaft may be reversed by reversing the field of the generator to which its motors are connected.