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A typical application of inrush current limiters is in the input stage of non-power factor corrected switching supplies, to reduce the initial surge of current from the line input to the reservoir capacitor. The most popular application is the inrush protection of the AC current in switching power supplies (SPS).
An inrush current limiter is a device or devices combination used to limit inrush current. Passive resistive components such as resistors (with power dissipation drawback), or negative temperature coefficient (NTC) thermistors are simple options while the positive one (PTC) is used to limit max current afterward as the circuit has been operating (with cool-down time drawback on both).
It cannot limit the inrush current unless it cools for more than 1 minute to get a higher resistance. Another disadvantage is that the NTC thermistor is not short-circuit-proof. Another way to avoid the transformer inrush current is a "transformer switching relay". This does not need time for cool down.
Current limiting reactor. The main motive of using current limiting reactors is to reduce short-circuit currents so that circuit breakers with lower short circuit breaking capacity can be used. They can also be used to protect other system components from high current levels and to limit the inrush current when starting a large motor. [5]
The inrush current will increase as the capacitance value increases, and the inrush current will increase as the voltage of the power source increases. This second parameter is of primary concern in high voltage power distribution systems. By their nature, high voltage power sources will deliver high voltage into the distribution system.
Moreover, the high inrush current stresses the power supply, which may lead to voltage dips. As a result, lifespan of sensitive equipment may be reduced. [1] Another common side-effect, especially in residential installations, is voltage sag in the site's power supply created by the high inrush current, visible as flickering lights.
Limiting can refer to a range of treatments designed to limit the maximum level of a signal. Treatments in order of decreasing severity range from clipping, in which a signal is passed through normally but sheared off when it would normally exceed a certain threshold; soft clipping which squashes peaks instead of shearing them; a hard limiter, a type of variable-gain audio level compression ...
In an electric power system, overcurrent or excess current is a situation where a larger than intended electric current exists through a conductor, leading to excessive generation of heat, and the risk of fire or damage to equipment.