Patent ID: 7595614

Claim:
A load tap changer, comprising: a first semiconductor device connected to a first gate trigger circuit; a second semiconductor device connected to a second gate trigger circuit; and a mechanical switch that shunts the first semiconductor device when the mechanical switch is in a first conducting position and shunts the second semiconductor device when the mechanical switch is in a second conducting position; wherein the mechanical switch is in electrical contact with a first pole when the switch is in the first conducting position, and wherein the mechanical switch is in electrical contact with a second pole when the switch is in the second conducting position; wherein the mechanical switch creates a first circuit between a source and a load through a first contact when the mechanical switch is in the first conducting position, and the mechanical switch creates a second circuit between the source and the load through a second contact when the mechanical switch is in the second conducting position; wherein movement of the mechanical switch from the first conducting position to the second conducting position, wherein the mechanical switch contacts neither the first or second pole, causes one of the gate trigger circuits to trigger its corresponding semiconductor device and complete a circuit through the corresponding semiconductor device for effecting engagement of a transformer tap.