Top 250+ Solved Testing and Commissioning of Electrical Equipment’s MCQ Questions Answer
Q. On what factor does the operating speed of the relay depend?
a. Rate of flux built up
b. Armature core air gap
c. Spring tension
d. All of these
Q. Protective relays can be designed to respond to ___________.
a. Light intensity, impedance
b. Temperature, resistance, reactance
c. Voltage and current
d. All of these
Q. What is the purpose of back up protection?
a. To increase the speed
b. To increase the reach
c. To leave no blind spot
d. To guard against failure of primary
Q. What is the major cause of the failure of the circuit breaker?
a. Trip circuit open
b. Trip latch defective
c. Spring defective
d. All of these
Q. Why are the isolators used?
a. Break abnormal current
b. Making under fault conditions
c. Breaking the circuit under no load condition
d. None of the above
Q. The isolators used in the transmission lines are capable of breaking
a. Fault current
b. No current
c. Charging current
d. Load current
Q. For which among the following the current ratings are not required?
a. Circuit breakers
b. Relays
c. Isolators
d. Load break switch
Q. What is the making to breaking current ratio for an extra high voltage circuit breaker?
a. More than 1
b. Equal to 1
c. Less than 1
d. A negative value
Q. Which of the following circuit breaker is highly reliable and has a least maintenance?
a. Oil circuit breakers
b. Air blast
c. Vacuum circuit breakers
d. SF6 circuit breakers
Q. The rating of the circuit breaker is usually determined on the basis of ____________ fault.
a. Symmetrical
b. Line to line
c. Single line to ground
d. Double line to ground
Q. Which among these circuit breakers produce the least arc energy?
a. Plain oil
b. Minimum oil
c. Air blast
d. Air break
Q. A thermal protection switch provides protection against what?
a. Overload
b. Temperature
c. Short circuit
d. Over voltage
Q. What does protective relay provide?
a. Provide additional safety to the circuit breaker in its operation.
b. Close the contacts when the actuating quantity attains a certain predetermined value.
c. Limit the arcing current during the circuit breaker operation.
d. Earth or ground any stray voltage.
Q. What is the main purpose of oil in oil circuit breakers?
a. Provide insulation
b. Quenching ar(C)
c. Provide cooling of contacts.
d. None of the above
Q. What is the advantage of using oil as the arc quenching medium?
a. Good cooling properties.
b. High dielectric strength.
c. Acts as an insulator.
d. All of these.