Free Expert Guides on Power Systems, Circuit Design & Electrical Troubleshooting

The primary function of an electrical circuit breaker is to provide opening and closing of the current carrying contacts. Although it is seems to be very simple. But we should remember, that, one circuit breaker remains at its closed position for maximum period of its life span. Very occasionally it is required to operate a circuit breaker for opening and closing its contacts.Hence circuit breaker operation must be very reliable without any delay or sluggishness. For achieving this reliability t

Various routine tests are performed for ensuring the quality, performance of a circuit breaker and these are Power frequency over voltage withstand test Dielectric test on auxiliary circuit and control circuit Measurement of resistanceof main circuit or contact resistance test Tightness test orSF6 gasleakage test Design and visual checks Mechanical operation tests.Let us discuss them one by one.Power Frequency Over Voltage Withstand TestThe power system may experience different temporary power o

The rating of a circuit breaker includes: Rated short circuit breaking current. Rated short circuit making current. Rated operating sequence of circuit breaker. Rated short time current.Short Circuit Breaking Current of Circuit BreakerThis is the maximum short circuit current which a circuit breaker (CB) can withstand before it, finally cleared by opening its contacts.When a short circuit flows through a circuit breaker, there would be thermal and mechanical stresses in the current carrying part

The electrical power demand is rising rapidly. Now days, huge quantity of electrical power is necessary to transmit from one place to other for fulfilling this rising power demand. Bulk power transmission can be most efficiently done through high voltage electrical power transmission system. Hence, high voltage system becomes most essential requirement for power transmission. The equipments used in these high voltage transmission system, should be capable of withstanding this high voltage stress

For maintenance of circuit breaker or circuit breaker maintenance, it must be first switched off and then isolated from both sides by opening concerned electrical isolator.At this no isolated condition the circuit breaker must be operated for local and remote condition yearly and when required. The circuit breaker should be operated electrically from local and remote then mechanically from local. This type of operation makes the breaker more reliable by removing any coating developed between sli

History of SF6SF6 or sulfur hexafluoride gas molecules are combined by one sulfur and six fluorine atoms. This gas was first realized in the year 1900 in the laboratories of the Faculte de Pharmacie de, in Paris. In the year of 1937, General Electrical Company first realized that SF6 gas could be used as gaseous insulating material. After the Second World War, i.e. in the middle of 20th century, the popularity of using sulfur hexafluoride gas as an insulating material in electrical system was ri

What Does MOCP Mean in Electrical Terms?MOCP stands for Maximum Over-Current Protection and is defined as the maximum allowable current rating for the over-current protection devices (such as a fuse or circuit breaker) associated with a piece of electrical equipment (e.g. a motor or air conditioner). MOCP is the maximum permissible rating or size of the circuit breaker that will properly disconnect the circuit or equipment under any anticipated fault condition.If the protective devices are overs

Aresidual current circuit breaker (RCCB)is an electrical safety device that detects and interrupts an electrical circuit when there is a leakage current to the ground. It protects people and equipment from electric shocks, fires, and other hazards caused by faulty wiring, insulation failure, or accidental contact with live parts.An RCCB works on the principle ofKirchhoff’s current law, which states that the sum of currents entering a node must equal the sum of currents leaving that node. In a no

The power system deals with voltage above 36KV, is referred as high voltage switchgear. As the voltage level is high the arcing produced during switching operation is also very high. So, special care is to be taken during the designing of high voltage switchgear. High voltage circuit breaker, is the main component of HV switchgear, hence high voltage circuit breaker (CB) should have special features for safe and reliable operation. Faulty tripping and switching operation of high voltage circuit

From 3 KV to 36 KV switchgear system is categorized as medium voltage switchgear or MV switchgear. These switchgears are of many types. They may metal enclosed indoor type switchgear, metal enclosed outdoor type switchgear, outdoor type switchgear without metal enclosure, etc. The interruption medium of this switchgear may be insulating oil, SF6 gas or vacuum. The main requirement of power network is to interrupt current during faulty condition irrespective of what type of CB is used in the MV s