| 摘要 |
<p>In order to reduce the switch-on surge in current in the operation of an inductive load provided with a magnetizable core at an alternating mains current, in particular in pulse group operation, a switch-off-reset impulse is applied to this load following switching-off of the inductive load from the alternating current mains. This impulse has a polarity phased opposite to the last pulse group halfwave. In this way the remanent induction of the transformer core is shifted in a defined manner to lower values so that a defined remanence state of the iron core can be assumed when starting the next pulse group. This permits peak-current-free switching-on under any load and pulse period conditions. The remanent induction of the transformer core can also be maintained in the sector occurring immediately following switching-off of the inductive load, thus at the end of a pulse group. For this purpose voltage of reduced effective value compared to the load, in particular small voltage phases which are in phase with the voltage application prior to the switching-off moment, is applied to the transformer in the pulse group pauses.</p> |
