| 摘要 |
529,929. Transmitting mechanical power. BUDD MANUFACTURING CO., E. G. June 12, 1939, Nos. 17153 and 17154. Convention dates. June 16, 1938, and July 20, 1938. [Class 38 (iv)] A power system for railway and other vehicles comprises a direct coupled turbine and alternator and one or more induction motors each geared to a driving axle or wheel and designed to absorb all the turbine torque at all stages of operation. Two or more turbine sets may be run in parallel and controlled by coupler throttles. The induction motors have means for changing the number of their poles. The frequency of the system at maximum speed may exceed 100 cycles. The system is started with the idling alternators over excited 45 per cent. and with the maximum motor pole number. It is accelerated by throttle control to half speed ; the throttle is then closed, the field excitation reduced to that required to maintain synchronism between alternators in parallel, the main circuit is opened and the motor pole number reduced after which the sequence is reversed and the system accelerated to full speed. The field strength of the alternator is reduced to normal during each acceleration stage and means responsive to turbine or vehicle speed may do this automatically. Fig. 2 shows control means comprising a throttle lever 120, controlling, in association with a follow up sector 144 and relay controlled reversible motor 141, a throttle 124. The lever is interlocked electrically and mechanically with a control drum 189 driven, when the control lever is in "off" position, through a single revolution by a motor 184. The drum then effects, in sequence, the open circuiting resistance 204 to produce minimum field strength of alternator 125, the opening of main switch 210, and the electromagnetic operation of the pole changing switch 164 and a motor 166, followed by the reverse operation and the preceding steps. The controller may also operate signals 284, 296. The actuation of the pole changing switch to positions appropriate to vehicle speed is effected by a centrifugal snap action switch 160 in association with the controller 189 and a switch 222, coupled to the pole changing switch. A centrifugal device 240 may operate a resistance switch 242 controlling field strength in one or more stages between 45 per cent. over excitation and normal field. |
