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A high-resistance connection (HRC) is a hazard that results from loose or poor connections in traditional electrical accessories and switchgear which can cause heat to develop, capable of starting a fire. [1] Glowing connections occur when relatively high current exists in a relatively large resistance object. Heat comes from power dissipation ...
A thermal switch (sometimes thermal reset or thermal cutout (TCO)) is a device which normally opens at a high temperature (often with a faint "plink" sound) and re-closes when the temperature drops. The thermal switch may be a bimetallic strip , often encased in a tubular glass bulb to protect it from dust or short circuit .
Glitched and garbled display on a workstation laptop with a defective graphics card that underwent extensive overheating from use in a hot environment. The second image shows the same laptop failing to operate properly due to the aforementioned graphics card defect, crashing the operating system and displaying a blue screen of death (albeit ...
A sudden fail-open fault can cause multiple secondary failures if it is fast and the circuit contains an inductance; this causes large voltage spikes, which may exceed 500 volts. A broken metallisation on a chip may thus cause secondary overvoltage damage. [1] Thermal runaway can cause sudden failures including melting, fire or explosions.
Every time the contacts of an electromechanical switch, relay or contactor are opened or closed, there is a certain amount of contact wear. If the contact is cycling without electricity (dry), the impact of the contact electrodes a slightly deformed by the resulting cold forging. [1]
Possible causes for overcurrent include short circuits, excessive load, incorrect design, an arc fault, or a ground fault. Fuses, circuit breakers, and current limiters are commonly used overcurrent protection (OCP) mechanisms to control the risks. Circuit breakers, relays, and fuses protect circuit wiring from damage caused by overcurrent. [1]
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When the contacts touch, the switch is closed; when the contacts are separated, the switch is open. The gap must be an insulating medium, such as air, vacuum, oil, SF 6. Contacts may be operated by humans in push-buttons and switches, by mechanical pressure in sensors or machine cams, and electromechanically in relays.