A protection device comprises a substrate, a fusible element and a heating element. The substrate comprises a first electrode and a second electrode on its surface. The fusible element is disposed on the substrate and connects to the first electrode and the second electrode at two ends. The fusible element comprises a first metal layer and a second metal layer disposed on the first metal layer. The second metal layer has a lower melting point than that of the first metal layer. The heating element is disposed on the substrate. In the event of over-voltage or over-temperature, the heating element heats up to melt and blow the fusible element. The second metal layer is 40-95% of the fusible element in thickness.

An overheat protection device and a varistor are provided. The overheat protection device comprises: a first electrode and a second electrode disposed to be spaced apart; a hot-melt wire located between the first electrode and the second electrode, the hot-melt wire being in electrical contact with the first electrode and the second electrode; and an insulator supporting the first electrode and the second electrode, wherein the hot-melt wire is melted into a liquid hot-melt material when the ambient temperature reaches a predetermined temperature, the liquid hot-melt material wets the first electrode and the second electrode, and the liquid hot-melt material does not wet the insulator at least at a portion located between the first electrode and the second electrode.

A three phase surge protection device is disclosed. In an embodiment a device include a stack comprising a first varistor, a second varistor and a third varistor, wherein the varistors are electrically connected to form a circuit and a first thermal disconnect configured to interrupt the circuit when a temperature of the first thermal disconnect exceeds a predefined temperature.

The invention relates to a disconnecting device for a surge arrester which is accommodated by a support body, and wherein plug contacts which are connected to at least one arrester element of the surge arrester extend from the support body. The invention further comprises a switching tongue which is connected at a first end to the arrester element via a thermal separating point and with a second end to one of the plug contacts. Furthermore, a spring-preloaded insulating disconnecting bracket which is pivotably mounted on the support body is provided, the spring preload acting on the thermal separating point via the switching tongue. According to the invention, the switching tongue is configured as a straight-surface, elongated, metallic, resiliently elastic disconnecting strip having a rectangular cross-section.

An electronic module for a power tool having an electric motor is provided including a printed circuit board (PCB), an inverter bridge circuit, a first conductive track disposed on the PCB and coupled to the power source, a second conductive track disposed on the PCB and coupled to the inverter bridge circuit, and a fuse strap provided between the first conductive track and the second conductive track. The fuse strap includes a main body spaced apart from the PCB, a first mounting portion mounted on the first conductive track via a first solder joint, and a second mounting portion mounted on the second conductive track via a second solder joint.

An installation structure of a temperature fuse is disclosed. The temperature fuse includes a first leg fixed to one surface of a printed circuit board (PCB), a bent part formed to be bent several times in an outer direction of the PCB from an end part of the first leg, and a second leg incorporated with the bent part and fixed to one surface of the PCB while being spaced apart from the first leg by a predetermined distance. The installation structure of the temperature fuse includes a third leg formed to extend from any one of the first leg and the second leg, a conductive member electrically connected to the third leg while being electrically isolated from the PCB, and a sensing part electrically connected to the third leg through the conductive member, and configured to detect whether a connection state between the third leg and the conductive member is normal.

The temperature sensitive pellet type thermal fuse includes a cylindrical case which has a first end and a second end, a temperature sensitive pellet, an insulating tube, a first lead which is inserted into the insulating tube and has an inner end serving as a contact portion, a movable contact which is electrically connected to the cylindrical case, a weak compression spring, a strong compression spring, and a second lead which is disposed on the second end of the cylindrical case. The movable contact includes a projecting contact portion which is provided at a central part of the movable contact, and the projecting contact portion and the contact portion of the first lead are in contact with each other inside the insulating tube.

The invention relates to a short-circuiting device for use in low-voltage and medium-voltage systems for the protection of property and persons, comprising: a switching element, which can be operated by the tripping signal of a fault detection device; two mutually opposite contact electrodes having power supply means, which contact electrodes can be brought into contact with an electrical circuit having connection points at different potential; furthermore, in at least one of the contact electrodes, a movable contact part, which is under mechanical preload and executes a movement to the further contact electrode with the assistance of spring force in the event of a short circuit; and a sacrificial element as a spacer between the contact electrodes, with an electrical connection between the sacrificial element and the switching element on the one hand and one of the contact electrodes on the other hand, in order to deliberately cause current-flow-induced thermal deformation or destruction of the sacrificial element. According to the invention, the movable contact part is in the form of a hollow cylinder which is closed on one side, and a spring for generating preload is inserted in the hollow cylinder. The hollow cylinder is movably guided in a complementary cutout in the first contact electrode, a sliding contact thus being formed. In the region of the base of the closed hollow cylinder, the cylinder wall of said hollow cylinder transitions into a cone at the outer circumference. Furthermore, a first pin-like extension, opposite to which a second pin-like extension insulated from the contact electrodes is situated, extends within the hollow cylinder, proceeding from the base. The sacrificial element, in the form of a bolt or screw, is arranged between the first and the second pin-like extension. A cutout, which has an internal cone and is matched to the external cone of the movable contact, is provided in the second contact electrode. The external cone and the internal cone form a bounce-free short-circuit contact region having frictional locking and interlocking connection on account of plastic deformation which occurs. Furthermore, according to the invention the switching element is designed as an auxiliary short-circuiter on the basis of an electric match.

A recyclable fuse includes a first contact and a second contact, and a current control unit allowing current to flow by electrically connecting the first contact and the second contact with each other when a temperature of the current control unit is less than a predetermined first temperature and preventing the current from flowing by electrically interrupting the first contact and the second contact from each other when the temperature of the current control unit is equal to or more than the predetermined first temperature.

A circuit protection element includes a vertical wall substantially perpendicular to a mounting surface of a circuit board in a mounted state; a first mounting part formed by being bent from the first end part of the vertical wall once and substantially parallel to the mounting surface; the second mounting part formed by being bent from the second end part of the vertical wall once and substantially parallel to the mounting surface; an elastic deformation part formed so as to project from the vertical wall in a predetermined direction, which has the contact part in the vicinity of an end part thereof on the opposite side to the vertical wall, and accumulates an elastic stress caused by elastic deformation thereof; and the self-locking part formed on the vertical wall and the elastic deformation part for maintaining the elastic deformation part in a state elastically deformed.