# Restriking voltage in Circuit Breakers - 1 - MCQs with answers

## Restriking voltage in Circuit Breakers - 1 - MCQs with answers

Q1. What is restriking voltage?

a. The transient voltage that appears across the circuit breaker contacts at the instant of arc extinction.
b. The transient voltage that appears across the circuit breaker contacts at the end of arc extinction.
c. Both (a) and (b)
d. None of above.

ANSWER: a. The transient voltage that appears across the circuit breaker contacts at the instant of arc extinction.

Q2. In a circuit breaker, the active recovery voltage depends upon which among these?

a. Circuit conditions.
b. Power factor.
c. Both (a) and (b)
d. None of the above

ANSWER: c. Both (a) and (b)

Q3. On what factor does the rate of rise of restriking voltage (RRRV) depend on?

a. System voltage.
b. Circuit power factor only
c. Switching conditions
d. Both (b) and (c).

ANSWER: d. Both (b) and (c).

Q4. Rate of rise of restriking voltage depend on_____________?

a. Type of circuit breaker.
b. Capacitance of the system.
c. Inductance of the system.
d. Both capacitance and inductance of the system.

ANSWER: d. Both capacitance and inductance of the system.

Q5. The stability of arc in vacuum depends on _________.

a. The contact material only.
b. The circuit parameters only.
c. The contact materials and its vapour pressure.
d. Both (b) and (c)

ANSWER: d. Both (b) and (c)

Q6. Why is it difficult to interrupt a capacitive circuit?

a. The current has a leading power factor.
b. The restriking voltage can be high.
c. Current magnitude is very small.
d. Stored energy in the capacitor is very high.

ANSWER: b. The restriking voltage can be high.

Q7. Recovery voltage is the value of rms voltage that reappears across the poles of a circuit breaker before_______________

a. Restriking voltage
b. Final arc extinction
c. Rise of voltage
d. All of the above

Q8. What is the interrupting medium in the contactor?

a. Air at atmospheric pressure.
b. SF6 gas
c. Oil
d. All of the above.