Air Blast Circuit Breaker - MCQs with answersQ1. Which type of air is used in air blast circuit breaker?
a. Ionised air
b. Air free from moisture
c. Air should have least CO2
d. Air must have oil mist.View Answer / Hide Answer
Q2. When using air blast circuit breaker, current chopping is a phenomenon observed when
ANSWER: b. Air free from moisture
a. A long overhead line is switched off.
b. A bank of capacitors is switched off.
c. A transformer on no load is switched off.
d. A heavy load is switched off.View Answer / Hide Answer
Q3. Why is the resistance switching used in a air blast circuit breaker?
ANSWER: c. A transformer on no load is switched off.
a. Reduce the magnitude of fault current.
b. Control the CB operating time.
c. Damp out the fast transient.
d. Change the fault current power factor.View Answer / Hide Answer
Q4. What is the type of air blast in cross blast type CB?
ANSWER: c. Damp out the fast transient.
a. The blast of air is along the arc.
b. The blast of air cuts across the arc.
c. Both (a) and (b)
d. None of the above.View Answer / Hide Answer
Q5. The air blast circuit breakers for 400 kV systems are designed to operate in how much time?
ANSWER: b. The blast of air cuts across the arc.
a. 0.1 s
b. 0.5 s
c. 50 ms
d. 100µsView Answer / Hide AnswerQ6. In axial blast type of CB, expansion of air takes place from?
a. High pressure to low pressure.
b. Low pressure to high pressure.
c. Always in high pressure.
d.Always in low pressure.View Answer / Hide Answer
Q7. What is the breaking capacity of the air blast circuit breakers?
ANSWER: a. High pressure to low pressure.
a. 5000 MVA
b. 6000 MVA
c. 7000 MVA
d. 10000 MVAView Answer / Hide Answer