Section 1: Electrical interview questions and answers about switchgear and protection What are the functions of protective relays? To detect the fault and initiate the operation of the circuit breaker to isolate the defective element from the rest of the system, thereby protecting the system from damages consequent to the fault. Give the consequences of… Read More »
Circuit breaker is a mechanical device designed to close or open contacts member thus closing or opening of an electrical circuit under normal or abnormal conditions. Circuit breakers are usually employed for the protection of electrical circuits, they are equipped with a trip coil connected to relay or other means. A circuit breaker is a… Read More »
Brushless motor also known as BLDC motor is a synchronous motor that gets power by a DC electric source. It uses an integrated inverter, which ultimately produces an AC electric signal to drive the motor. British scientist Michael Faraday first experimented with the idea of the electromagnetic induction motor in the early 1800’s. During that… Read More »
A contactor is an electrically controlled switch used for switching an electrical power circuit , similar to a relay except with higher current ratings. Contactor is in fact an electromechanical switch. Low-voltage Contactor is an electrically controlled switch used for switching an electrical power circuit, similar to a relay except with higher current ratings. A… Read More »
What is a balun? A Balun is special type of transformer that performs two functions i.e. impedance transformation and balanced to unbalanced transformation. The term balun is a contraction of “balanced to unbalanced transformer” Why do we need a balun? Baluns are important because many types of antennas (dipoles, yagis, loops) are balanced loads, which… Read More »
In this method of inter-connection the similar ends either the ‘start’ or ‘finish’ are joined together at point N. This common point N is called star point or neutral point. Ordinarily only three wires are carried to the external circuit giving 3-phase, 3-wire star connected system but sometimes a fourth-wire, known as neutral wire is… Read More »