摘要 |
A d-c motor drive system, useful for propelling and retarding electrically propelled traction vehicles, wherein the armature winding has a first terminal coupled through an armature chopper to a first polarity conductor of a d-c source, and a second terminal coupled through a breaker switch to a second polarity conductor of the d-c source. First and second controlled rectifiers are connected across the first and second conductors in a self commutating circuit such that they conduct sequentially and alternatively. Means are provided for varying their respective conduction time intervals to control the voltage at their junction. Field winding means are coupled from the junction of the controlled rectifiers to the junction of the armature second terminal and the breaker. During the motoring mode with the breaker closed field current flows in a first direction. During the retarding mode with breaker open and the second terminal of the armature coupled by a diode to the first conductor, field current flows in an opposite direction to permit d-c motor to operate as a retarding generator.
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