Patent ID: 9054522
Filing Date: 2015-06-09
Classification: B32B,E04D,H01F,H01H,H02H,Y02A,Y02B

Abstract:
1. In combination with: a transformer having a plurality of taps; a load shunt; a main vacuum tube switch connected to the load shunt; and a selector connected to the main vacuum tube switch and connectable directly one at a time to each of the taps to conduct electricity from the taps to the load shunt, a load changeover switch assembly comprising: respective auxiliary branches each connected directly to a respective one of the taps and to the load shunt and each comprising, connected in series with one another: a respective resistor; a respective auxiliary vacuum tube switch, and a respective isolating switch closable to conduct electricity from the respective tap to the load shunt through the respective auxiliary resistor and auxiliary vacuum tube and openable to open-circuit the respective auxiliary branch; and control means for, when the selector disconnects from a connected one of the taps and moves toward a selected one of the taps, closing the auxiliary switch of the selected tap and then, when the selector connects to the selected tap, opening the auxiliary switch of the selected tap.