Current Interrupter Tutorials

Current Interrupter Tutorials Facts, Definitions, Uses Etc.

Circuit Breaker
An electromagnetic device that opens a circuit automatically when current exceeds a predermined value. It is capable of interrupting large values of fault power MVA resulting from the faults on the power system. It consists of current carrying contacts called electrodes which, under predetermined conditions, separate to interrupt the circuit. An arc is struck between them when the contacts are separated. This arc is extinquished either by lengthening the arc, cooling the arc, or splitting the arc. Due to this, the arc resistance increases resulting in the system voltage becoming unable to maintain the arc and the arc gets extinguised.

HRC Fuse
High Rupturing Capacity cartridge fuse is a good interrupting device because it gives a fast fault clearing and exhibits property of cut-off. It is useful in low and medium voltage installation to provide overload and short-circuit protection. The fuse element is of copper alloyed with tin. Its characteristics vary with the type of material and the shape of fuse element. The rated current of the fuse is the current which it can carry continously without deterioration.

Switchgear
The name given to a family of devices covering a wide range of equipment concerned with switching and interrupting the currents during normal and abnormal conditions. The equipment associated with controlling, protecting, regulating and measuring also belong to the switchgear family. It includes switches, fuses, Circuit breaker, isolator, relays, Control panel, metering panels lighting arresters, Current transformer, Potential transformer, and other associated items. The circuit breakers are assited by other components of the protective scheme. A switch is used for opening and closing the circuit. Fuse is used for over-current protection. The purpose of switching and protection is served by the swithgear. A circuit breaker is the switching and interrupting device in a switchegear.

Reactors
The purpose, of reactors incorporated in circuit breakers is to limit the short-circuit current flowing to a safe value thus providing protection of instruments. The concist of large coils of high self-inductance and very low resistance. Main type of reactors are magnetically shielded reactor, and the shielded reactor.

Answer all Frequent Questions About Circuit Breaker
1. The function of protective relay in a circuit breaker is to close the contacts when the actuating quantity reaches a certain predetermined value.
2. Low voltage circuit breakers have rated voltages of less than 1000 volts.
3. When A high voltage Alternating current circuit breaker is tested for endurance, it is tested for at least 1000 opening closing operations.
4. For high voltage Alternating Current circuit breaker, the rated short circuit current is passed for 3 three second.
5. Vacuum is not a type of the contactor for circuit breaker.

Current Interrupter Tutorials