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A terminal fault is a fault that occurs at the circuit breaker terminals. The circuit breaker interrupts a short-circuit at current zero, at this instant the supply voltage is maximum and the recovery voltage tends to reach the supply voltage with a high frequency transient. The normalized value of the overshoot or amplitude factor is 1.4.
Faults in an installation are, for example, overload and short circuit. [1] [2] There are four ways in which selectivity is achieved: [3] Current selectivity: different breaking capacities; Time selectivity: time delay before tripping of a breaker; Energy based selectivity: analysis of the current waves
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 ...
The maximum short-circuit current that a breaker can interrupt is determined by testing. Application of a breaker in a circuit with a prospective short-circuit current higher than the breaker's interrupting capacity rating may result in failure of the breaker to safely interrupt a fault.
They can be performed on a circuit involving capacitors and inductors as well, by expressing circuit elements as impedances and sources in the frequency domain. In general, the concept of source transformation is an application of Thévenin's theorem to a current source, or Norton's theorem to a voltage source. However, this means that source ...
If connected in series with the circuit it simply prevents reversed current, but if connected in parallel it can shunt the reversed supply, causing a fuse or other current limiting circuit to open. All semiconductor diodes have a threshold voltage – typically between 0.5 volt and 1 volt – that must be exceeded before significant current ...
The SI unit of electrical current. Ampère's circuital law The mathematical relation between the integral of the magnetic field over some closed curve to the current passing through the region bound by the curve. Ampère's force law The mathematical relation between the force between two current carrying conductors and the current flowing in them.
Conditional short-circuit current is the value of the alternating current component of a prospective current, which a switch without integral short-circuit protection, but protected by a suitable short circuit protective device (SCPD) in series, can withstand for the operating time of the current under specified test conditions.