Quiz On Circuit Breaker

15 Questions | By Mikkilisuresh123 | Last updated: Mar 20, 2022 | Total Attempts: 161

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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.

SF₆gas
- 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.