GB191502841A - Improvements in and relating to Systems of Electric Ship Propulsion. - Google Patents

Abstract

2841. British Thomson-Houston Co., [General Electric Co.], Feb. 22. Regulating.-In a system of ship propulsion where electric motors are employed to drive the propellers, a controller is arranged to control successively the electric circuits and the admission valves of the prime movers driving the generators. Where two units are employed, the motor units may be simultaneously operated, or one controller may control one unit independently. The ship is reversed in five steps, shutting off, steam from the turbines, de-energizing the generator field, reversing the motor connexions, energising the generator field, and admitting steam to the turbine. Two units are shown in Figs. 1 and 2 in engine rooms A, B separated by a bulkhead 10. In the engine room A, a turbine 11 drives an alternator 14 which is excited by main and auxiliary machines 17, 18 and is connected to a pair of propeller motors 15. The alternator 14 may be connected also to the pair of motors 25 associated primarily with the alternator 24 driven by the turbine 21 in the room B. The exciters are driven by small auxiliary turbines 178, 187 or, in some cases, they may be coupled to the shafts of the main turbines. Each engine room has a controller of the type shown in Fig. 4. The drum 60 is rotated by the handle 74 through gearing 73, and an indicator 75 is attached to show the movement of the drum. The drum 61 is operated similarly from the handle 84. The drum spindles are connected by bevel-gearing to two sleeves 78, 70 loosely mounted on a common shaft 71 and carrying cams 79, 89. The cam followers are attached to arms loosely mounted on the shaft 93. A sleeve on the shaft 93 has a central pin 128, engaging a fork on the spindle of the auxiliary controller 62 so that the rotation of the spindle by the handle 131 causes the sleeve to move axially and one of the pins 125, 126 to enter a hole in a plate carried by one of the followers of the cams 79, 89. Locking-plates 134, 135 are indented and one is locked by a sector 137 each time the controller 62 is moved from its zero position, so that only one of the drums 60, 61 can be operated unless the controller 62 is in its central position. The controller 60 connects the alternator 14 to the motors 15, and the controller 61 connects it to the motors 25. To operate each pair of motors from its own alternator, the switch 143 is thrown to the right and the switch 144 to the left. If both pairs of motors are to be controlled from room A, both switches are thrown to the right, while for operation from room B, both switches are thrown to the left. An arm 94, Fig. 3, is rigidly attached to the shaft 93 and to the actuating-rod 95 of the turbinegoverning mechanism, which is of the type described in Specification 3026/13. The arm 99 of the governor 96 is connected by a link to the floating lever 101 consisting of two similar members held together by a spring 102. The lever 101 is connected by links to the valve rod of a pilot motor 103 which operates the cam shaft 107 for the admission valves of the main turbine. A spring 115 tends to force the rod 95 in a direction to open the valves. When control is exercised from engine room A and the auxiliary controller 62 is moved to the left-hand position as viewed in Fig. 2, the controller 61 is locked by the sector 137 and the controller 60 is free. The switch 143 is thrown manually to the right and the switch 19 is closed. In the first ahead position of the controller 60, the coil 38 is energized and the switch 16 moved to its ahead position. In the second position, the field switch 150 is closed to connect the exciters 17, 18 to the field of the alternator 14, and in the third position, the field circuit of the machine 18 is closed through the constant resistance 153 and the adjustable resistance 152. Further movement of the controller 60 opens the steam admission valves 12 through the mechanism shown in Figs. 3 and 4, the initial movement of the auxiliary controller 62 having moved the sleeve on the shaft 93 so that the pin 125 has engaged the follower of the cam 79. To reverse the ship, the controller 60 is turned back, closing the valves 12, opening the fields of the exciter 18 and alternator 14, and de-energizing the coil 38 of the reversing switch. As its movement is continued in the astern positions, the coil 39 is energized to move the switch 16 to its astern position, the alternator field switch 150 is closed, and then the field circuit of the auxiliary exciter 18 is closed. Further movement opens the valves 12, but preferably steam is not admitted to the turbine until the motors and alternator have pulled into synchronism. The motors 25 in the room B are controlled in a similar manner by the controller 61 when the auxiliary controller 62 is moved in the opposite direction to that described. When both pairs of motors are to be controlled from room A, the switches 19, 42 are closed and the auxiliary controller 62 is left in its central position and both the controllers 60, 61 are operated. These are electrically interlocked so that they must occupy corresponding positions before the desired connexion is made. Both pins 125, 126 engage the cam followers in this case and the shaft 93 from which the valves 12 are controlled can only move as permitted by that controller which has moved least from its neutral position.