Search results
Results From The WOW.Com Content Network
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 ...
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 ...
In practical situations, when an air coil freeze stat is not used, bypassed, or defeated, the air coil can freeze, and this causes a lack of air flow to the facility. [3] By contrast, when a water coil freeze stat is not used, the water coil can get so cold that it can freeze the cooling liquid in the exchanger and burst the exchanger. [ 5 ]
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 ...
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.
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]
Image credits: tereddits #2. A friend of my brother's named Dave habitually ditched high school. One winter we got a pretty good snowstorm and his dad made him shovel the sidewalk before he left ...
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 ...