Fast earthing switch for interrupting non-short-circuit currents

A fast earthing switch comprising:

• two contacts of which at least one contact is movable in relation to the other contact between a closed position, in which the contacts are connected, and an open position, in which the contacts are unconnected, said contacts defining an arcing region in which an arc is generated during a current interrupting operation and in which an arc-quenching medium is present,
• a cylinder-like guiding tube in which the at least one movable contact forming a piston is slidably arranged for linearly moving between the closed position and the open position, whereby
• the guiding tube is closed at an upper end so that the piston defines a first compression chamber with the upper end for thereby decelerating movement of the piston when moving into the open position and/or
• the guiding tube is closed at a thereto opposite lower end so that the piston defines a second compression chamber with the lower end for thereby decelerating movement of the piston when moving into the closed position, and
• the piston is provided as disc-like piston sliding on an inner surface of the guiding tube and having a thereto orthogonal arranged piston rod linearly extending in moving direction within the guiding tube, and
• the disc-like piston comprises at least one piston bar-like element extending from the disc-like piston linear in moving direction towards the upper end and/or the lower end and the upper end and/or the lower end comprises a respective piston bar-like opening through which the piston bar-like element passes when the piston reaches the open position and/or the closed position, or
• the lower end comprises at least one lower bar-like element extending from the lower end linear towards the upper end and the disc-like piston comprises a respective lower bar-like opening through which the lower bar-like element passes when the piston reaches the closed position.

A method for decelerating movement of a piston in a fast earthing switch comprising:

• two contacts of which at least one contact is movable in relation to the other contact between a closed position, in which the contacts are connected, and an open position, in which the contacts are unconnected, said contacts defining an arcing region in which an arc is generated during a current interrupting operation and in which an arc-quenching medium is present,
• a cylinder-like guiding tube in which the at least one movable contact forming the piston is slidably arranged for linearly moving between the closed position and the open position, whereby
• the guiding tube is closed at an upper end so that the piston defines a first compression chamber with the upper end, and/or
• the guiding tube is closed at a thereto opposite lower end so that the piston defines a second compression chamber with the lower end and
• the piston is provided as disc-like piston sliding on an inner surface of the guiding tube and having a thereto orthogonal arranged piston rod linearly extending in moving direction within the guiding tube, and comprising the step of:
• decelerating movement of the piston when moving into the open position and/or into the closed position, whereby
• the disc-like piston comprises at least one piston bar-like element extending from the disc-like piston linear in moving direction towards the upper end and/or the lower end and the upper end and/or the lower end comprises a respective piston bar-like opening through which the piston bar-like element passes when the piston reaches the open position and/or the closed position, or
• the lower end comprises at least one lower bar-like element extending from the lower end linear towards the upper end and the disc-like piston comprises a respective lower bar-like opening through which the lower bar-like element passes when the piston reaches the closed position.