Quiz On Circuit Breaker
.
- 1.The medium employed for extinction of arc in air circuit breaker is
- A.
(A) SF6
- B.
(B) Oil
- C.
(C) Air
- D.
(D) Water.
- 2.Which of the following circuit breakers is preferred for EHT application
- A.
(A) Air blast circuit breakers
- B.
(B) Minimum oil circuit breakers
- C.
(C) Bulk oil circuit breakers
- D.
(D) SF6 oil circuit breakers.
- 3.For high voltage, ac circuit breakers, the rated short circuit current is passed for
- A.
(A) 0.01 sec
- B.
(B) 0.1 sec
- C.
(C) 3 seconds
- D.
(D) 30 seconds.
- 4.Interrupting medium in a contactor may be
- A.
(A) air
- B.
(B) oil
- C.
(C) SF6 gas
- D.
(D) any of the above.
- 5.In air blast circuit breakers, the pressure of air is of the order of
- A.
(A) 100 mm Hg
- B.
(B) 1 kg/cm2
- C.
(C) 20 to 30 kg/cm2
- D.
(D) 200 to 300 kg/cm2
- 6.SF6 gas is
- A.
(A) sulphur fluoride
- B.
(B) sulphur difluoride
- C.
(C) sulphur hexafluorine
- D.
(D) sulphur hexafluoride.
- 7.SF6 gas
- A.
(A) is lighter than hydrogen
- B.
(B) is lighter than air
- C.
(C) has density 2-times as compared to that of air
- D.
(D) has density 5 limes as compared to that of air.
- 8.The pressure of SF6 gas in circuit breakers is of the order of
- A.
(A) 100 mm Hg
- B.
(B) 1 kg/cm2
- C.
(C) 3 to 5 kg/cm2
- D.
(D) 30 to 50 kg/cm2.
- 9.While selecting a gas for circuit breaker, the property of gas that should be considered is
- A.
(A) high dielectric strength
- B.
(B) non-inflammability
- C.
(C) non-toxicity
- D.
(D) all of the above.
- 10.A sudden short-circuit in an ac system causes a rise in __________ in the short-circuited phase.
- 11.The voltage appearing across the circuit breaker pole after final current zero is called __________ voltage.
- 12.The voltage across the circuit breaker pole after final current zero is recovery voltage.
- A.
True
- B.
False
- 13.Air circuit breakers are used for voltages above 12 kV.
- A.
True
- B.
False
- 14.Arcing contacts of circuit-breakers are generally made of copper tungsten alloy.
- A.
True
- B.
False
- 15.The insulation requirements of switchgear are determined by __________ voltage.
Questions: 5 | Attempts: 4843 | Last updated: Apr 30, 2019
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