Top 150+ Solved Switch Gear and Protection MCQ Questions Answer
Q. Ionization in circuit breaker is facilitated by
a. high temperature
b. increase of mean free path
c. increasing field strength
d. all of the above
Q. In a circuit breaker the basic problem is to
a. maintain the arc
b. extinguish the arc
c. transmit large power
d. emit the ionizing electrons
Q. Overheating of relay contacts or contact born out is due to
a. slow making and breaking of load circuit contacts
b. foreign matter on the contact surface
c. too low contact pressure
d. all of the above
Q. Interruption of large currents by relay requires
a. arc suppressing blow out coils
b. wide separation of the opened contacts
c. high speed opening of contacts
d. all of the above
Q. Shunt capacitance is neglected while considering
a. short transmission line
b. medium transmission line
c. long transmission line
d. medium and long tr
Q. The time of closing the cycle, in modern circuit breakers is
a. 0.003 sec
b. 0.001 sec
c. 0.01 sec
d. 0.10 sec
Q. Insulation resistance of high voltage circuit breakers is more than
a. 1 mega ohms
b. 10 mega ohms
c. 100 mega ohms
d. 500 mega ohms
Q. H.R.C. fuses provide best protection against
a. overload
b. reverse current
c. open-circuits
d. short-circuits
Q. The delay fuses are used for the protection of ________ .
a. motors
b. power outlet circuits
c. fluorescent lamps
d. light circuits
Q. Which of the following is the least expensive protection for overcurrent is low voltage system ?
a. Rewireable fuse
b. Isolator
c. Oil circuit breaker
d. Air break circuit breaker
Q. Resistance grounding is used for voltage between
a. 33kVto66kV
b. HkVto33kV
c. 3.3kVandllkV
d. none of the above
Q. The contacts of high voltage switches used in power system are submerged in oil. The main purpose of the oil is to
a. lubricate the contacts
b. insulate the contacts from switch body
c. extinguish the arc
d. all of the above
Q. In Railway applications ______ circuit breaker is used.
a. SFe
b. bulk oil
c. minimum oil
d. air break
Q. To protect most of the electrical equipment handling low power, thetypes of relays used are
a. thermocouple
b. electronic and bimetallic
c. both (a) and (b)
d. none of the above