| 摘要 |
<p>1280467 Control of motors TRACKED HOVERCRAFT Ltd 9 Oct 1969 [16 Oct 1968] 49019/68 Heading H2J A track-guided air cushion vehicle comprises a linear induction motor stator 15 which cooperates with a reaction rail for propelling the vehicle, at least one D.C. fan motor 9 for supplying pressurized air for the air cushion, and an inverter 20 for converting a main D.C. power supply to A.C. for the stator 15. A portion of the unit 20 is adapted to be used as a D.C. chopper to provide increasing voltage to start the fan motor. When contactor 34 is opened and contactor 38 is closed, diode 29 and thyristor 26 within the inverter section 31, together with the armature 32, supplemented by inductor 30, form a chopper circuit wherein the diode 29 passes load current during "off" periods of the thyristor 26. To start the fan motor, a controller 50 cuts-off all the thyristors 26, 27, except for the thyristor 26 in the part 31 which is regulated to increase the motor voltage. When the fan motor reaches full speed, contactor 38 is opened and contactor 34 closed to connect the fan motor across the main D.C. source. Thereafter, the controller 50 receives a signal to adjust the frequency of the inverter.</p> |
