| 摘要 |
PURPOSE:To prevent the wastage of contact points caused by an arc and the deterioration of a surrounding insulating medium by a method wherein a movable contact point is shifted while a fixed contact point and an auxiliary contact point are being bridged, and each auxiliary contact point is connected to the respective adjoining fixed contact point through the intermediary of a voltage control element. CONSTITUTION:A movable contact point 80 is brought to come in contact with a fixed contact point, and it is connected to a high-tension side tap 4. An auxiliary contact point 13 is provided between the fixed contact point 12 on the high- tension side and the fixed contact point 14 on the low-tension side. At this point, the movable contact point is brought into the state wherein it is contacted to both of its fixed point and the adjoining one auxiliary contact point from the state wherein it is contacted to one fixed contact point only, and then it is shifted to the state wherein it is contacted to the auxiliary contact point only. Also, the control voltage of the voltage control element 90 connected to the auxiliary contact point 13 is set at the voltage lower than the output voltage of the tap and higher than the intertap voltage. |
