Image: Tap changing switch

Description: Animation of an on-load transformer tap changer, illustrating how taps can be selected without either interrupting supply or short-circuiting winding turns. The tap changer starts at tap position 2, with load supplied directly via the right hand connection. Diverter resistor A is short-circuited, diverter B is unused. If the tap changer is moved to tap 3, the following sequence occurs: Switch 3 closes, an off-load operation. Rotary switch turns, breaking one connection and passing load current through diverter resistor A. Rotary switch continues to turn, connecting between contacts A and B. Load now supplied via diverter resistors A and B, winding turns bridged via A and B. Rotary switch continues to turn, breaking contact with diverter A. Load now supplied via diverter B alone, winding turns no longer bridged. Rotary switch continues to turn, shorting diverter B. Load now supplied directly via left hand connection. Diverter A is unused. Switch 2 opens, an off-load operation. The animation then shows the tap changer returning to its starting position by reversing the above sequence of operations.
Title: Tap changing switch
Credit: Transferred from en.wikipedia to Commons.
Author: BillC at English Wikipedia
Usage Terms: Creative Commons Attribution-Share Alike 3.0
License: CC-BY-SA-3.0
License Link: http://creativecommons.org/licenses/by-sa/3.0/
Attribution Required?: Yes