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A fuse can clear a fault within a quarter cycle of the fault current, while a circuit breaker may take around half to one cycle to clear the fault. The response time of a fuse can be as fast as 0.002 seconds, whereas a circuit breaker typically responds in the range of 0.02 to 0.05 seconds.
An asymmetric or unbalanced fault does not affect each of the phases equally. Common types of asymmetric fault, and their causes: line-to-line fault - a short circuit between lines, caused by ionization of air, or when lines come into physical contact, for example due to a broken insulator. In transmission line faults, roughly 5% - 10% are ...
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).
The fuse element, or "fuse link", is the replaceable portion of the assembly that melts and breaks the circuit when the electric current through it exceeds its rated current value. There are many types of fuse elements for many different uses such as a type T fuse also known as a "slow-blow fuse" being used for sidelines.
Circuit-breakers can be placed at portions of a circuit in series to the path of current it will affect. If more current than expected goes through the circuit-breaker, the circuit breaker "opens" the circuit and stops all current. A fuse is a common type of circuit breaker that involves direct effect of Joule-overheating.
The prospective short-circuit current that can occur under short circuit conditions should not exceed the rated breaking capacity of the apparatus, otherwise breaking of the current cannot be guaranteed. The current breaking capacity corresponds to a certain voltage, so an electrical apparatus may have more than one breaking capacity current ...
In electrical engineering, IEC 60269 is a set of technical standards for low-voltage power fuses. [1] The standard is in four volumes, which describe general requirements, fuses for industrial and commercial applications, fuses for residential applications, and fuses to protect semiconductor devices.
Resettable fuses - PolySwitch devices. A resettable fuse or polymeric positive temperature coefficient device (PPTC) is a passive electronic component used to protect against overcurrent faults in electronic circuits. The device is also known as a multifuse or polyfuse or polyswitch.