| 摘要 |
In this DC actuation circuit for drives in short-distance vehicles having two and more DC series-characteristic motors (4, 10) connected in parallel, as the motor speed rises automatic field attenuation takes place in travel mode whilst in brake mode the field attenuation can be controlled. Since inadmissibly high differences in the loading of the motors can arise due to machine tolerances, the armature currents of the motors (4, 10) which are connected in parallel are adjusted to be the same by influencing the exciter currents. This adjustment acts in the timing range of the clocking period in which the field currents are freewheeling. The adjustment facility for a control is provided by means of series field resistors (14, 15) which are located in series in the field windings (17, 19) and can be bypassed by means of control thyristors (18, 20). When the armature currents are identical, both thyristors (18, 20) are fired at the start of the freewheeling of the field and in the event of deviations one of the thyristors is not fired or fired late as a result of which the corresponding field current decays more quickly and a field current is produced which is smaller on average. <IMAGE>
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