A drive unit is provided for a moving contact of a vacuum tube. The drive unit has a tube pin which is conductively connected to the moving contact, a drive which is connected to the tube pin, and a conductor bridge. The drive moves the tube pin. The conductor bridge is directly conductively connected to the tube pin and a stationary conductor and bridges a travel of the tube pin between a conductive switching state of the vacuum tube and a non-conductive switching state. A magnet drive is provided, which contains a first magnet element, which is connected to the tube pin, and a second magnet element. The two magnet elements are configured to build up a magnetic force between them when current is flowing through the vacuum tube and in this way generates a contact-pressure force of the moving contact onto a fixed contact of the vacuum tube.

The invention relates to an electric switch that serves to switch on and/or off electric devices and for this purpose has a contact system in the switch housing. By means of a manual actuating element or a remotely controlled actuator, a switching operation can be effected.

A variable force key, comprising a housing, a central shaft, and a magnetic ring, the central shaft extends into the housing, the top end of the center shaft is fixedly provided with a key cap seat, the central shaft can reciprocate in the housing in the vertical direction, the bottom end of the central shaft is fixedly provided with a limit member, the outer wall or inner wall of the bottom end of the limit member is provided with a flange, the magnetic ring sleeves the outer wall of the limit member or is arranged inside the limit member and located at the upper end of the flange. The variable force key further comprises an electromagnet or a hollow coil, which is arranged at the bottom in the housing, and when the central shaft moves downward, the electromagnet or the hollow coil can penetrate inside the limit member.

The emergency stop switch unit 2 as an operation switch unit includes a direct operation part 20A and an alternative operation part 20B. The direct operation part 20A has an emergency stop button 21 adapted to be directly operated. The alternative operation part 20B is adapted to be linked with the direct operation part 20A and alternatively operates the emergency stop button 21 in place of the direct operation part 20A. The alternative operation part 20B has a reception part 32 that detects a remote operation of the emergency stop button 21 and an electromagnetic solenoid 3 that actuates the emergency stop button 21 on the basis of the remote operation detected by the reception part 32.

The emergency stop switch unit 2 as an operation switch unit includes a direct operation part 20A and an alternative operation part 20B. The direct operation part 20A has an emergency stop button 21 adapted to be directly operated. The alternative operation part 20B is adapted to be linked with the direct operation part 20A and alternatively operates the emergency stop button 21 in place of the direct operation part 20A. The alternative operation part 20B has a reception part 32 that detects a remote operation of the emergency stop button 21 and an electromagnetic solenoid 3 that actuates the emergency stop button 21 on the basis of the remote operation detected by the reception part 32.

A fuse in form of breaking fusant by fusing breaking and mechanical breaking includes hollow shell; arc extinguishing medium filled in the shell; at least one piece of fusant arranged in the shell; and conductive terminals provided as penetrating through shell wall and capable to be connected to external circuit, two ends of the fusant are respectively connected with the conductive terminals, at least one breaking device that mechanically breaks the fusant is provided in the shell; driving device arranged outside the shell, after receiving external excitation signal, drives the breaking device to break the fusant in one of linear and rotational displacement modes or their combination; blocking structures are arranged between the breaking device and the shell wall; and the fusant located in the arc extinguishing medium is provided with weak positions where mechanical breaking strength of the fusant is reduced and fusing is easy to be achieved.

An electromagnetic energy converter including two plates each having an inner face; a flux variation device arranged between the inner faces, and which includes a first prismatic part, a magnet and a second prismatic part, and is arranged to pivot about an axis between two equilibrium positions, and for which the first and second prismatic parts each come into contact with an inner face; and a coil designed to be crossed by a magnetic flux generated by the magnet and guided by the two plates in a first direction when the device is in one equilibrium position, and in a second direction when said device is in the other equilibrium position.

In an embodiment a switching device includes two fixed contacts and a rotary contact bridge in a switching chamber in a gas-tight region, wherein the rotary contact bridge is rotatable about an rotation axis, wherein, in a first switching state, the fixed contacts are electrically conductively connected by the rotary contact bridge, wherein, in a second switching state, the rotary contact bridge is rotatable about the rotation axis relative to the first switching state, and the fixed contacts are electrically insulated from one another, and wherein the gas-tight region includes H.sub.2.

A variable force key, including a housing, a central shaft, and a magnetic ring, the central shaft extends into the housing, the top end of the center shaft is fixedly provided with a key cap seat, the central shaft can reciprocate in the housing in the vertical direction, the bottom end of the central shaft is fixedly provided with a limit member, the outer wall or inner wall of the bottom end of the limit member is provided with a flange, the magnetic ring sleeves the outer wall of the limit member or is arranged inside the limit member and located at the upper end of the flange. The variable force key further includes an electromagnet or a hollow coil, which is arranged at the bottom in the housing, and when the central shaft moves downward, the electromagnet or the hollow coil can penetrate inside the limit member.

Systems and apparatuses include an automatic transfer switch including a source pole coupled with a power source, a first load pole coupled with a first load, a second load pole coupled with a second load, a first switch selectively coupling the first load pole to the source pole, and a second switch selectively coupling the second load pole to the source pole.