Top 250+ Solved Testing and Commissioning of Electrical Equipment’s MCQ Questions Answer
Q. A fuse is never inserted in
a. neutral wire
b. negative of D.C. circuit
c. positive of
d. C. circuit
Q. Which of the following circuit breakers is used for the railway electrification?
a. Air blast circuit breaker
b. SF6 circuit breaker
c. Bulk oil circuit breaker
d. Minimum oil circuit breaker
Q. The stability of arc in vacuum depends on _________.
a. The contact material only.
b. The circuit parameters only.
c. The contact materials and its vapour pressure.
d. Both (b) and (c)
Q. SF6 is which type of gas?
a. Electro positive
b. Electro negative
c. Both (a) and (b)
d. None of these
Q. What is the average rate of rise of restriking voltage upto the first peak?
a. 525 * 103kV / sec
b. 453 * 103kV / sec
c. 582 * 103 kV / sec
d. 467 * 103 kV / sec
Q. Circuit breakers usually operate under
a. Steady short circuit current
b. Sub transient state of short circuit current
c. Transient state of short circuit current
d. None of these
Q. What is the actuating quantity for the relays?
a. Magnitude
b. Frequency
c. Phase angle
d. All of these
Q. Which among these are the main characteristics of a fuse element?
a. Low melting point
b. High conductivity
c. Least deterioration due to oxidation
d. All of the above
Q. What is the making capacity of the circuit breaker?
a. Less than the asymmetrical breaking capacity of the breaker
b. Greater than the asymmetrical breaking capacity of the breaker
c. Equal to the asymmetrical breaking capacity of the breaker
d. Equal to the symmetrical breaking capacity of the breaker
Q. In a circuit breaker the contact space is ionised by what?
a. Field emission from the contact surface.
b. Thermal emission from the contact surface.
c. Thermal ionisation of gas.
d. All of above.
Q. A three phase, 33 kV oil circuit breaker is rated 1200 A, 2000 MVA, 3s. What isits symmetrical breaking current?
a. 1200 A
b. 3600 A
c. 35 kA
d. 104.8 kA
Q. What should be the value of fusing factor?
a. Equal to zero
b. Equal to one
c. Less than one
d. More than one
Q. What is the relation between the fusing current and the diameter of the wire?
a. I = k d3
b. I = k d3/2
c. I = k d2
d. I = k d2/3
Q. The making and breaking currents of a 3 phase ac circuit breakers in powersystems are respectively in ________form.
a. rms value, rms value
b. instantaneous value, rms value
c. rms value, instantaneous value
d. instantaneous value, instantaneous value