Top 250+ Solved Testing and Commissioning of Electrical Equipment’s MCQ Questions Answer
Q. On which of the following routine tests are conducted ?
a. Oil circuit breakers
b. Air blast circuit breakers
c. Minimum oil circuit breakers
d. All of the above
Q. Which of the following medium is employed for extinction of arc in air circuitbreaker ?
a. Water
b. Oil
c. Air
d. SF6
Q. Thermal overload relays are used to protect the motor against over current due to
a. short-circuits
b. heavy loads
c. grounds
d. all of the above
Q. Magnetic circuit breaker has ______ trip action.
a. delayed
b. instantaneous
c. both of the above
d. none of the above
Q. D.C. shunt relays are made of
a. few turns of thin wire
b. few turns of thick wire
c. many turns of thin wire
d. many turns of thick wire
Q. The relay operating speed depends upon
a. the spring tension
b. the rate of flux built up
c. armature core air gap
d. all of the above
Q. In order that current should flow without causing excessive heating or voltage drop,the relay contacts should
a. have low contact resistance
b. be clean and smooth
c. be of sufficient size and proper shape
d. have all above properties
Q. Circuit breakers usually operate under
a. transient state of short-circuit current
b. sub-transient state of short-circuit current
c. steady state of short-circuit current
d. after D.C. component has ceased
Q. Circuit breakers are essentially
a. current carrying contacts called electrodes
b. arc extinguishers
c. circuits to break the system
d. transformers to isolate the two systems
Q. The current zero interruption, in oil and air blast circuitbreakers, is achieved by
a. lengthening of the gap
b. cooling and blast effect
c. both (A) and (B)
d. deionizing the oil with forced air
Q. Air blast circuit breaker is used for
a. over currents
b. short duty
c. intermittant duty
d. repeated duty
Q. An efficient and a well designed protective relaying should have
a. good selectivity and reliability
b. economy and simplicity
c. high speed and selectivity
d. all of the above
Q. Burden of a protective relay is the power
a. required to operate the circuit breaker
b. absorbed by the circuit of relay
c. developed by the relay circuit
d. none of the above
Q. A differential relay measures the vector differencebetween
a. two currents
b. two voltages
c. two or more similar electrical quantities
d. none of the above