Practice Test: Question Set - 10
1. Thermal circuit breaker has
- (A) Delayed trip action
- (B) Instantaneous trip action
- (C) Both of the above
- (D) None of the above
2. Magnetic circuit breaker has _________ trip action.
- (A) Delayed
- (B) Instantaneous
- (C) Both of the above
- (D) None of the above
3. The relay operating speed depends upon
- (A) The spring tension
- (B) The rate of flux built up
- (C) Armature core air gap
- (D) All of the above
4. Air blast circuit breaker is used for
- (A) Over currents
- (B) Short duty
- (C) Intermittent duty
- (D) Repeated duty
5. Directional relays are based on flow of
- (A) Power
- (B) Current
- (C) Voltage wave
- (D) All of the above
6. The voltage appearing across the contacts after opening of the circuit breaker is called _________voltage.
- (A) Recovery
- (B) Surge
- (C) Operating
- (D) Arc
7. The ground wire should not be smaller than No ________ copper.
- (A) 2
- (B) 4
- (C) 6
- (D) 10
8. The reflection coefficient at the open circuited end of a transmission line.
- (A) Zero
- (B) Infinity
- (C) Unity
- (D) None of the above
9. Discrimination between main and back up protection is provided by the use of relays which are
- (A) Fact
- (B) Sensitive
- (C) Slow
- (D) None of the above
10. Short-circuit currents are due to
- (A) Single phase to ground faults
- (B) Phase to phase faults
- (C) Two phase to ground faults
- (D) Any of these
11. Distance relays are generally
- (A) Split-phase relays
- (B) Reactance relays
- (C) Impedance relays
- (D) None of the above
12. Which of the following devices will receive voltage surge first travelling on the transmission line?
- (A) Lightning arresters
- (B) Relays
- (C) Step-down transformer
- (D) Switchgear
13. Arc in a circuit breaker is interrupted at
- (A) Zero current
- (B) Maximum current
- (C) Minimum voltage
- (D) Maximum voltage
14. If the fault occurs near the impedance relay, the VII ratio will be
- (A) Constant for all distances
- (B) Lower than that of if fault occurs away from
the relay
- (C) Higher than that of if fault occurs away
from the relay
- (D) None of the above
15. The power loss is an important factor for the design of
- (A) Transmission line
- (B) Motor
- (C) Generator
- (D) Feeder
Blogger Comment
Facebook Comment