TAP CHANGER FOR LOAD-SELECTOR STEPPING SWITCHES AND FOR LOAD SELECTORS (DESIGN VERSIONS) Russian patent published in 1999 - IPC

FIELD: electrical engineering. SUBSTANCE: tap changer has two switching contacts movable in two directions. First contact is, essentially, power contact member connected through first vacuum switch to load tap; second one is resistive contact member also connected to load tap through series-connected second vacuum switch and intermediate resistor. Both main and resistive contact members are free to move irrespective of each other; power contact member always reaches new fixed contact member in steps before resistive contact member leaves former fixed contact member. Vacuum switches are used in power and resistive circuits. EFFECT: provision for minimizing switching load. 5 cl, 9 dwg