| 摘要 |
1,255,226. Control systems for D.C. motors driving vehicles. M. N. YARDNEY. 18 March, 1969, No. 14117/69. Headings H2H and H2J. A vehicle propulsion system comprising a prime mover, an electric motor and an electric battery is provided with means whereby when the vehicle is moving at a speed below a preset speed the electric motor, which drives the vehicle, is supplied by the battery and when the speed of the vehicle is above the preset speed the driving motor is supplied by a generator driven by the prime mover. A D.C. motor 10 driving a vehicle by way of ashaft 12 is supplied from D.C. supply lines 25, 26 over a pulse width modulator 14, the motor speed being controlled by a control pedal 48 which varies a signal from a potentiometer 58 to the modulator 14 whereby the pulse width is varied to alter the level of the output voltage 16, 18 fed to the motor 10. A tachogenerator 42 provides a signal, representing the vehicle speed to an amplifier 40 wherein it is compared with a preset signal obtained from a potentiometer 44 which signal presets the speed at which the motor supply changes from a battery 22 to an alternator 24 driven by an I.C. engine 30, the alternator output being rectified and supplied to the pulse width modulator 14. When the speed of the vehicle reaches the transition point the signal from the tachogenerator 42 causes the amplifier to produce zero output thus de-energizing relay 36 and closing contact 38. Closure of contact 38 energizes a starter 32 to start the engine 30 whereupon the output of the alternator/rectifier device 24, 23 supplies the motor 10 and also charges the battery 22. Should the vehicle speed drop below the preset value the amplifier 40 produces an output to energize relay 36 thus opening the contact 38 whereupon the engine 30 is stopped and the supply to the motor 10 reverts to the battery 22. The control pedal 48 controls the speed of the engine 30 as well as the width of the pulses produced by the modulator 14. In a second embodiment a governor may be arranged to control the change over from battery to alternator and vice-versa.
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