Patent ID: 9324493
Filing Date: 2016-04-26
CPC Classification: H01F,H01H

Claim Text:
1. A tap changer for an electrical transformer, comprising a liquid-filled actuator, the actuator comprising: a movable piston having a longitudinal axis; an energy storing device, in mesh with the piston and being configured for storing energy during axial movement of the piston in a direction and for inducing axial movement of the piston in an opposite direction when the energy stored in the energy storing device is released; wherein a space is defined within the actuator, the space having a volume which varies with the axial movements of the piston; and at least one choke valve arranged for controlling a flow of the liquid, with which the actuator is filled, passing through the choke valve between the variable volume space and an outside of the actuator as a result of said axial movement of the piston when the energy stored in the energy storing device is released.