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A small circuit breaker typically has a manual control lever to switch the circuit off or reset a tripped breaker, while a larger unit may use a solenoid to trip the mechanism, and an electric motor to restore energy to springs (which rapidly separate contacts when the breaker is tripped).
Some thermal switches must be reset manually after having tripped. This type is used when an automatic and unattended restart would create a hazardous condition, such as sudden startup of a powerful motor without warning. These types of thermal cutouts are usually reset by pressing a push-button by hand or with a special tool.
This cooling usually takes a few seconds, though a tripped device will retain a slightly higher resistance for hours, unless the power in it is weaker, or has been often used, slowly approaching the initial resistance value.
These power strips have a reset button for the circuit breaker, which is used to return the strip to service after an overload has caused it to trip. On some power strips, the red, lighted rocker switch actually controls a thermal circuit breaker which flips to off when tripped. Resetting is done by flipping the switch back on. [11] [12]
In electrical engineering, a protective relay is a relay device designed to trip a circuit breaker when a fault is detected. [ 1 ] : 4 The first protective relays were electromagnetic devices, relying on coils operating on moving parts to provide detection of abnormal operating conditions such as over-current, overvoltage , reverse power flow ...
Automatically closing the breaker after it has tripped and stayed open for a brief amount of time, usually after 1 to 5 seconds, is a standard procedure. [ 5 ] Reclosers are often used as a key component in a smart grid , as they are effectively computer controlled switchgear which can be remotely operated and interrogated using supervisory ...
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Once triggered, they depend on the current-limiting circuitry of the power supply or, if that fails, the blowing of the line fuse or tripping the circuit breaker. The name is derived from having the same effect as throwing a crowbar over exposed power supply terminals to short the output.