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 novel temperature-triggered fuse device is configured to be activated at a designer-specified ambient temperature by utilizing wetting force among a pair of wetting material bays and a solder bridge or a solder ball. The solder bridge or the solder ball is typically positioned on top of the pair of wetting material bays separated by an electrically-insulated gap. Preferably, the wetting material bays are at least partly made of gold, nickel, or other elements suitable for generating an increased wetting force to the solder bridge or the solder ball upon increases in ambient temperature. The novel temperature-triggered fuse device can be integrated into various types of integrated circuits (IC's), or can function as a discrete fuse connected to one or more electronic components for robust protection from power surges and/or thermal runaway-related device malfunctions, meltdowns, or explosions. Various methods of producing the temperature-triggered fuse device are also disclosed herein.

Apparatus, systems, and methods for determining a temperature excursion are provided. In one example, a system can comprise a temperature switch component that experiences a temperature excursion associated with a metal alloy of the temperature switch component and one or more electrodes, wherein the temperature excursion is based on a temperature of the metal alloy exceeding a defined threshold value. Additionally, the system can comprise a radio frequency identification tag component that receives a signal, from an external reader device, utilized to determine that the temperature excursion has occurred based on a parameter change, associated with the temperature excursion, from a first parameter to a second parameter different than the first parameter.

A fuse element for an electric circuit, arranged on a circuit board of the electric circuit, has a surface area for fastening and establishing an electric contact on the circuit board, a first deforming area adjacent the surface area, a second deforming area connected to the first deforming area via a central area, the second deforming area including a contact area that abuts the circuit board, and a hook-shaped element insertable into an opening adjacent the contact area, the hook-shaped element is insertable into the opening by elastic deformation of the fuse element in the direction of the circuit board and, after insertion of the hook-shaped element into the opening and positive holding of the hook-shaped element on a lower surface of the circuit board, the first and second deforming areas exert an elastic force on the surface area in the direction away from the circuit board.

A surge protective device (SPD) module includes a varistor and an electrical conductor. The varistor includes a hole defined therein and extending through the varistor. The electrical conductor extends through the hole in the varistor.

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.

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.

A varistor component and a method for securing a varistor component are disclosed. In an embodiment a varistor component includes a first external contact, a second external contact, a varistor electrically connected to the first external contact, a path between the varistor and the second external contact and an active releasing device having a shutter and a heat sensitive element, wherein, under abnormal operation conditions, the heat sensitive element releases the shutter, and the shutter moves along a straight line and closes the path between the varistor and the second external contact.

A high-voltage direct-current thermal fuse including: a fusible component having two fusible alloy support arms parallel to each other; a fluxing agent; a fusing cavity; and two pins. The fusible component and the fluxing agent are sealed within the fusing cavity. The two pins are respectively connected to the two support arms. Technically, the fluxing agent only needs to have contact with the fusible alloy. Practically, the fluxing agent is usually coated over the fusible alloy. The fusible component in the high-voltage direct-current thermal fuse of the present application is a U-shaped structure having two parallel support arms. A high electric field intensity is generated when an arc is being cut off, as a result, the electrons repel each other, and the arc is lengthened, thereby increasing the speed of cutting off the arc.

A thermal fuse for an electrical circuit is described, with a contact arm by way of which two electrical conductors are electrically conductively connected to each other, wherein the connection of the contact arm to at least one of the two conductors is a soldered joint, which loses its strength when a activation temperature of the fuse is reached. In accordance with this disclosure a permanent magnet is provided, which generates a magnetic force, which lifts the contact arm from at least one of the two conductors as soon as the soldered joint loses its strength.