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A residual-current device (RCD), residual-current circuit breaker (RCCB) or ground fault circuit interrupter (GFCI) [a] is an electrical safety device that interrupts an electrical circuit when the current passing through a conductor is not equal and opposite in both directions, therefore indicating leakage current to ground or current flowing to another powered conductor.
A shunt-trip unit appears similar to a normal breaker and the moving actuators are ganged to a normal breaker mechanism to operate together in a similar way, but the shunt trip is a solenoid intended to be operated by an external constant-voltage signal, rather than a current, commonly the local mains voltage or DC. These are often used to cut ...
Another cause of nuisance tripping is due to accumulated or burden currents caused by items with lowered insulation resistance. This may occur due to older equipment, or equipment with heating elements, or even wiring in buildings in the tropics where prolonged damp and rain conditions can cause the insulation resistance to lower due to ...
At two multiples of the rated current, the recloser's rapid trip curve can cause a trip (off circuit) in as little as 1.5 cycles (or 30 milliseconds). During those 1.5 cycles, other separate circuits can see voltage dips or blinks until the affected circuit opens to stop the fault current.
An automatic trip is an action performed by some system, usually a safety instrumented system, programmable logic controller, or distributed control system, to put an industrial process into a safe state. It is triggered by some parameter going into a pre-determined unsafe state.
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.
Listing price on eBay: $2,500 There were countless Japanese-made, cartoon-like ceramic figurines made during the 1950s, and some of the most valuable (and collectible) are vintage salt and pepper ...
A kick will occur when the bottom hole pressure(BHP) of a well falls below the formation pressure and the formation fluid flows into the wellbore. There are usually causes for kicks some of which are: Failure to keep the hole full during a trip; Swabbing while tripping; Lost circulation; Insufficient density of fluid; Abnormal pressure