The present invention proposes a protection device which has a large rated voltage and a large rated current, which is capable of sufficiently suppressing arc generation during activation, and which is also capable of providing suitable protection against overcurrent due to short circuiting or the like of a main circuit. The protection device of the present invention includes (i) a protection element which includes a first thermal fuse and a resistor, and in which the resistor generates heat as a result of current passing through the resistor when there are abnormalities, and the first thermal fuse is activated due to this heat and interrupts the current, (ii) a PTC element and a second thermal fuse which are electrically connected in parallel to the first thermal fuse and which are electrically connected in series to each other, and (iii) a current fuse which is electrically connected in series to the first thermal fuse.

A fuse element comprises a low melting point metal layer, a first high melting point metal layer having a higher melting point than a melting point of the low melting point metal layer, and a restricting portion including a high melting point material having a higher melting point than a melting point of the low melting point metal layer and configured to restrict flow of the low melting point metal or deformation of a layered body constituted by the first high melting point metal layer and the low melting point metal layer.

A device for dissipating a surge includes at least three metal oxide varistors (MOVs). Each of the MOVs may be positioned adjacent to each other. Each of the MOVs may have two contact surfaces. Contact surfaces of adjacent MOVs are electrically connected together. The at least three MOVs include a first outer MOV, a second outer MOV, and at least one inner MOV positioned between the first outer MOV and the second outer MOV. The first outer MOV and the second outer MOV have a greater voltage at a given current than at least one of the at least one inner MOV. The device further includes a first connector electrically coupled to at least one of the at least three MOVs. The device further includes a second connector electrically coupled to at least another of the at least three MOVs.

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 reflowable thermal fuse including a fuse body, a conductive composite element disposed within the fuse body, first and second conductive terminals connected to the conductive composite element and extending out of the fuse body, a removable barrier covering a surface of the conductive composite element and in electrical communication with the first and second conductive terminals, and a solvent element disposed on the removable barrier and separated from the conductive composite element by the removable barrier, wherein the removable barrier has a fusing temperature that is greater than a reflow temperature of the reflowable thermal fuse.

A thermal limiter system for an electric motor includes a thermal limiter fuse having a hollow contact element anchored by solder to at least one of first and second terminals of the fuse. A coaxial spring element causes the hollow contact element to slidably release and separate from one of the first and second terminals due to overheating of the solder that is not caused by a flow of electrical current. The system also includes stator mounting blocks and a stator cooling jacket for a motor to be thermally protected.

A printed circuit board (PCB) assembly according to one embodiment of the present disclosure includes a first pad; a second pad disposed to be spaced apart from the first pad; and a thermal fuse provided with a first terminal and a second terminal which are each coupled to the first pad and the second pad by soldering. Here, a contact area between the first pad and the first terminal is smaller than that between the second pad and the second terminal.

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.

A surge protective device (SPD) module includes a module housing, first and second module electrical terminals mounted on the module housing, an overvoltage clamping element electrically connected between the first and second module electrical terminals, and a thermal disconnector mechanism. The thermal disconnector mechanism is positioned in a ready configuration, wherein the overvoltage clamping element is electrically connected with the second module electrical terminal. The thermal disconnector mechanism is repositionable to electrically disconnect the overvoltage clamping element from the second module electrical terminal. The thermal disconnector mechanism includes: an electrode electrically connected to the overvoltage clamping element; a disconnect spring elastically deflected and electrically connected to the electrode in the ready configuration; a solder securing the disconnect spring in electrical connection with the electrode in the ready configuration; and a heat sink member thermally interposed between the electrode and the solder, the heat sink member having a thermal capacity. The solder is meltable in response to overheating of the overvoltage clamping element. The disconnect spring is configured to electrically disconnect the overvoltage clamping element from the second module electrical terminal when the solder is melted. The thermal capacity of the heat sink member buffers and dissipates heat from the overvoltage clamping element to prevent the solder from melting in response to at least some surge currents through the SPD module.

This disclosure relates to a heat sensitive electrical safety device with a manually resettable device and an automatically resettable fuse. The manually settable fuse prolongs the serviceable life of the automatically resettable fuse.