Patent GB-190929250-A (GB)
Title: Improvements in and relating to Systems of Ship Propulsion.
IPC: B63H23/24
Filed: 1909-12-14
Granted: 1910-12-01
Abstract: 29,250. British Thomson-Houston Co., [General Electric Co.]. Dec. 14. Dynamos and motors combined for transmitting power.-In an electric power transmission system for the propulsion of ships, the propeller shafts are provided with two induction motors, one having a squirrel-cage rotor and a variablepole stator, and the other having a wound rotor with a variable resistance and preferably a constant-pole stator Each propeller shaft is provided with its own prime mover and generator, the generators being arranged to run in parallel or singly to supply the motors; and the switches between the bus-bars, generators, and motors, and the switches varying the rotor resistances are electro-magnetically locked when the generators are excited. When the engineroom is divided into two parts by means of a longitudinal bulkhead, arrangements are made for controlling the turbine stop - valve and switches of the generator and motors of the starboard engine from the port engine-room, and vice versa. The arrangement of the port engine-room shown in Fig. 1 consists of a turbine 5 coupled to an alternator 9, induction motors 14, 15 mounted upon the propeller shaft 13, and switches 24, 27, 28 connecting the alternator 9 and motors 14, 15 to the bus-bars 12.. The admission of steam to the turbine 5 is controlled by a combined emergency and stop valve 6 arranged to be operated from either side of the bulkhead. The motor 14 is provided with a squirrel-cage rotor and a switch 16 for varying the number of poles of its stator; while the motor 15 has a wound rotor provided with a resistance 20, the value of which is varied by means of a device 19. The port bus-bars 12 and the starboard bus-bars 12<a> may be connected by a switch 21, which may be operated by a handle 22 in the port engine-room or by a handle 23 in the starboard engine-room. Similarly, the connecting and reversing switches 27, 28 of the motors 14, 15 may be operated by handles 29, 30 or 31, 32. The switches 16, 24, 27, 28 and the device 19 are provided with locking-devices 54, 36, 37, 38 and 39, arranged to be energized from the exciting-circuit 10 of the alternator so that the switches and device cannot be operated when the exciting-circuit of either generator is closed. In a modification, the locking-devices are energized by the alternating-current circuit or controlled by relays in that circuit. The exciting and interlocking circuits are controlled by switches 52, 53 preferably arranged to be controlled from either engine-room; while, to prevent racing of the turbine when the exciting- circuits are broken, the switches 52, 53 are interlocked with the admission valves so that these switches cannot be opened until the valves are closed An alternative method for preventing racing of the turbine when the load is removed, consists of an electric locking-device, placed either in the exciting-circuit or the main circuit, which operates to close the valve when the exciting-circuit is broken. When the poleratio of the motors 14, 15 is two to one, both motors may be provided with pole-changers and resistances. Each of the locking-devices consists of a magnet 40, having its armature 40<a> mounted upon a pivoted lever 41, the free end of which engages a notched disk 43 mounted upon the shaft 44 of the switch or device handle, Fig. 2.