| 摘要 |
<p>1,224,561. Control of D.C. motors. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 22 April, 1968, No. 18825/68. Heading H2J. When a split-field series motor 10 is operating in the forward direction, switch 100 is closed and trigger module 60 supplies trains of pulses to a bridge comprising thyristors Th1 Th2 so as to render them alternately conductive. The speed of the motor is controlled by a pressuresensitive potentiometer 90 which has a neutral position for stopping the motor. Rectification of the supply is provided by diodes D1, D2, whilst diode D3 acts as a flywheel diode. When the motor is in reverse, the thyristors Th3, Th4, are effective. The diodes D1, D2 again act as rectifiers, whilst diode D4 becomes the freewheel diode. The potentiometer 90 may be replaced by a pressure-sensitive resistor, deceleration being effected by reversal of power. The power supply to the trigger modules 60, 70 is obtained from diode bridge 80 which also supplies a magnetic brake.</p> |
