TAP SWITCHING APPARATUS USED IN LOADING CASE

PROBLEM TO BE SOLVED: To make compact the whole of a tap switching apparatus used in the loading case of a transformer and realize its stable current application and its sure switching operation, by using a two-resistances and three-valves switching method. SOLUTION: The tap switching apparatus used in the loading case of a transformer comprises: two current limiting resistances and resistance-valves each of which is so connected in series with each other as to be interposed between a neutral point of the transformer and each of two movable contacts of a tap selecting device for selecting the taps of a tap winding; a converting switch S comprising static contacts each of which is interposed between each movable contact and each current limiting resistance of the tap selecting device and comprising a movable contact for selecting one of the static contacts; and also a main valve whereby the movable contact of the converting switch and the neutral point of the transformer. Moreover, in the lower end portion of a driving axis 2 driven in a rotary way by an energy accumulating device 1, this tap switching apparatus used in the loading case of the transformer has: a vacuum-valve opening/closing mechanism 30 having a cum 5 for opening/closing the resistance-valves and main valve in a predetermined order and having an actuating portion for opening/closing by the rotation of the cum 5 the resistance-valves and main valve so disposed in the outer periphery of the center of this cum that they correspond to the ones of the respective three-phases of the transformer; and above the cum 5 a movable portion 50 for driving concentrically to the driving axis 2 the movable contact of the converting switch S. COPYRIGHT: (C)2008,JPO&INPIT