Top 150+ Solved Switch Gear and Protection MCQ Questions Answer
Q. The main function of a fuse is to
a. protect the line
b. open the circuit
c. protect the appliance
d. prevent excessive currents
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. The arcing contacts in a circuit breaker are made of
a. copper tungsten alloy
b. porcelain
c. electrolytic copper
d. aluminium alloy
Q. Which of the following medium is employed for extinction of arc in aircircuit breaker ?
a. Water
b. Oil
c. Air
d. SF6
Q. With which of the following, a circuit breaker must be equipped for remote operation ?
a. Inverse time trip
b. Time-delay trip
c. Shunt trip
d. None of the above
Q. A thermal protection switch can protect against
a. short-circuit
b. temperature
c. overload
d. over voltage
Q. Arc in a circuit behaves as
a. a capackive reactance
b. an inductive reactance
c. a resistance increasing with voltage rise across the arc
d. a resistance decreasing with voltage rise across the arc
Q. Thermal circuit breaker has
a. delayed trip action
b. instantaneous trip action
c. both of the above
d. none of the above
Q. Relays can be designed to respond to changes in
a. resistance, reactance or impedance
b. voltage and current
c. light intensity
d. all above
Q. Thermal overload relays are used to protect the motor against overcurrent 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