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Rain sensor on the windshield of a car. A rain sensor or rain switch is a switching device activated by rainfall. There are two main applications for rain sensors. The first is a water conservation device connected to an automatic irrigation system that causes the system to shut down in the event of rainfall.
A residual-current device (RCD), residual-current circuit breaker (RCCB) or ground fault circuit interrupter (GFCI) [a] is an electrical safety device, more specifically a form of Earth-leakage circuit breaker, that interrupts an electrical circuit when the current passing through line and neutral conductors of a circuit is not equal (the term residual relating to the imbalance), therefore ...
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.
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 ...
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.
This is most likely to occur on a carbureted engine in cold weather, after a running engine has been shut off briefly before being restarted. Doing so can cause the choke valve to configure the mixture for a cold engine start, despite higher actual temperatures, resulting in an overly rich mixture and flooded engine.
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.
The high temperatures can also cause the contact metals to more rapidly oxidize and corrode. Contacts reach end of life for one of two reasons. Either the contacts fail to BREAK because they are stuck (welded) closed, or the contacts fail to make (high resistance) because of contact corrosion or because excessive material is lost from one or ...