A relay includes a housing, an electric contact system in the housing, an electromagnetic system in the housing, and a magnetic blowing arc-extinguish device. The electric contact system includes a static contact with a static contact portion and a movable contact with a movable contact portion. The electromagnetic system is configured to drive the movable contact to move between a closed position in which the movable contact is in electrical contact with the static contact and an opened position in which the movable contact is separated from the static contact. The magnetic blowing arc-extinguish device includes a permanent magnet statically provided near the static contact and configured to lengthen an electric arc between the static contact portion and the movable contact portion by an electromagnetic force to extinguish the electric arc.

The present disclosure relates to an arc extinguishing unit of a molded case circuit breaker with a barrier provided between a fixed contact and a movable contact when a circuit is cut off, including fixed contacts fixed to part of a base assembly case; movable contacts that come contact or are separated from the fixed contacts; and an arc extinguishing part that extinguishes an arc generated when the movable contacts are separated from the fixed contacts. The arc extinguishing part includes a pair of side plates; multiple grids installed at a fixed interval between the pair of side plates; and arc barriers each installed on a base assembly case in a slidable manner, and configured to be in an open state of being separated from the movable contacts when a normal current flows on the circuit or is cutoff, and to close when a fault current is cutoff.

In an embodiment a thermal protection device includes a housing, a varistor partly embedded in the housing, wherein the housing electrically insulates the varistor, and wherein the varistor includes a partly uninsulated contact surface, an inner wall of insulating material arranged adjacent to the contact surface of the varistor, a window in the inner wall configured to allow an electrical connection of the contact surface of the varistor in an operational state of the thermal protection device and a moveable insulation block configured to cover the window in the inner wall to insulate the varistor in a region of the window of the inner wall in a fault state of the thermal protection device.

In an embodiment a thermal protection device includes a housing, a varistor partly embedded in the housing, wherein the housing electrically insulates the varistor, and wherein the varistor includes a partly uninsulated contact surface, an inner wall of insulating material arranged adjacent to the contact surface of the varistor, a window in the inner wall configured to allow an electrical connection of the contact surface of the varistor in an operational state of the thermal protection device and a moveable insulation block configured to cover the window in the inner wall to insulate the varistor in a region of the window of the inner wall in a fault state of the thermal protection device.

A system for interrupting ignition is disclosed. Specific implementations of ignition interrupters may include a first conductive tab configured to couple to a spark plug; a second conductive tab configured to couple to a spark plug wire; a first tab holder coupled with the first conductive tab; a second tab holder coupled with the second conductive tab, where the second conductive tab overlaps with the first conductive tab; a sled positioned perpendicularly to a plane of the first conductive tab and the second conductive tab, the sled coupled between the first conductive tab and the second conductive tab; a first spring coupled to the sled; and a second spring coupled to the sled; where the sled may be configured to move to an open position in the gap between the first conductive tab and the second conductive tab, decompressing the first spring and the second spring.

An apparatus includes an electrical switch that includes (i) multiple first electrical contacts and (ii) a second electrical contact configured to bridge the first electrical contacts in order to form at least one electrical connection. The apparatus also includes a shape-memory actuator configured to move the second electrical contact in order to selectively open the electrical switch and break the at least one electrical connection. The shape-memory actuator may be configured to be returned to an original shape and the second electrical contact may be configured to be returned to a bridging position in order to reset the apparatus. The apparatus may further include a shutter member configured to be moved between the first electrical contacts in order to prevent re-bridging of the first electrical contacts and to extend an arc-gap between the first electrical contacts.

A power circuit shut off device includes a housing and a switch portion provided in the housing, and an operating member configured to turn on or turns off the switch portion. The switch portion includes a pair of terminals arranged along a bottom face of the housing, an electric conductive member having contact point portions and that is elastically urged toward the pair of terminals, and an insulating movable member configured to move along a direction in which the pair of terminals are arranged. The pair of terminals are brought into electric conductive to each other when the pair of terminals contact the contact point portions respectively. The insulating movable member is moved between a shut-off position and a conductive position by an operation on the operating member.

An apparatus includes an electrical switch that includes (i) multiple first electrical contacts and (ii) a second electrical contact configured to bridge the first electrical contacts in order to form at least one electrical connection. The apparatus also includes a shape-memory actuator configured to move the second electrical contact in order to selectively open the electrical switch and break the at least one electrical connection. The shape-memory actuator may be configured to be returned to an original shape and the second electrical contact may be configured to be returned to a bridging position in order to reset the apparatus. The apparatus may further include a shutter member configured to be moved between the first electrical contacts in order to prevent re-bridging of the first electrical contacts and to extend an arc-gap between the first electrical contacts.

The present disclosure relates to an arc extinguishing unit of a molded case circuit breaker with a barrier provided between a fixed contact and a movable contact when a circuit is cut off. The arc extinguishing unit includes fixed contacts fixed to part of a base assembly case; movable contacts that contact or are separated from the fixed contacts; and an arc extinguishing part that extinguishes an arc generated when the movable contacts are separated from the fixed contacts. The arc extinguishing part includes a pair of side plates; multiple grids installed at a fixed interval between the side plates; and arc barriers each rotatably installed on the side plates, and configured to open between the movable contacts and the fixed contacts by being rotated when a current flows on the circuit, and to close between the movable contacts and the fixed contacts when the current is cut off.

A thermally protected metal-oxide varistor is provided, including a disconnecting unit, a first varistor assembly and a second varistor assembly. The first varistor assembly and the second varistor assembly are connected in series through a low-melting-point alloy layer; wherein when the low-melting-point alloy layer is fused, the disconnecting unit acts to cut off the low-melting-point alloy. The two varistors are connected directly through solder joints without any transition connection member. The heat transfer path is reduced to the shortest path, and a faster response is realized compared to conventional products formed by a varistor and a disconnecting unit when abnormal over-current passes. Moreover, the slider functions as a physical separator capable of isolating the two varistors after the solder joints are fused, which further diminishes the risk of fire occurrence caused by the failure of instantly blocking current by the disconnecting unit when the varistor breaks down by over-current.