| 摘要 |
1432348 Control of D.C. motors CABLEFORM Ltd 6 June 1973 [8 June 1972] 26671/72 Heading H2J A D.C. compound motor A of an electric vehicle is driven by closure of an accelerator pedal switch MS and a tripswitch TS to energize a relay C1/3 whose contacts C1.1 change over to connect the motor and its series field winding SF to a battery B through a pulsing thyristor switch S, the other relay contacts C1.2 and C1.3 respectively energizing forward or reverse contactors CF, CR for winding SF and de-energizing a relay C2/1 whose contacts C2.1 open to switch out the shunt field winding AF of the motor. To brake, switch MS is opened to cause contacts C1.1 to connect the armature A across a resistor R and contacts C1.3 to energize the relay C2/1 to connect the winding AF across the battery B through an adjustable resistor VR whose value determines the degree of braking. If contactors CF, CR are reversed during driving without opening switch MS, braking is effected by reverse energization of the motor. A normally-open switch 55 is closed when the vehicle driver's seat is occupied.
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