| 摘要 |
PURPOSE:To eliminate a circulating current and make a current-limiting impedance and an auxiliary arcing contact unnecessary by a method wherein, after a prescribed tap is opened, a load current is born by a non-linear resistance until a tap of the next step is connected. CONSTITUTION:Taps 2, 3 are provided to a transformer winding 1. Main arcing contacts 6, 7 are connected to the taps 2, 3 through tap-selectors 4, 5. A load 11 is connected to a collector contact 10. A non-linear resistance 12 is provided between the collector contact 10 and the tap-selector 5. Because a transient load current is born by the non-linear resistance 12, a circulating current is eliminated. Therefore, a current-limiting impedance and an auxiliary arcing contact are not necessary. Moreover, as a current to be discontinued by a main arcing contact is the load current only, the circuit-breaking burden of the main arcing contact is reduced. |
