Q.451 Blind spot in a point in zones of protection where
A. Partial protection is available
B. No protection is available
C. Complete protection is available
D. None of the above
Ans.: B
Q.452 Which zone of distance relay is affected by the transient over reach phenomenon?
A. First zone
B. Second zone
C. Third zone
D. None of the above
Ans.: A
Q.453 In differential protection scheme a stabilizing resistance is required to
A. Block the relay current
B. Increase the relay sensitivity
C. Reduce the effect of non linear CTs
D. None of above
Ans.: C
Q.454 The magnetizing inrush current in a transformer is rich in the
A. Second harmonic component
B. Third harmonic component
C. Fifth harmonic component
D. Seventh harmonic component
Ans.:A
Q.455 The detection of unbalance in current in large induction is rich in the done by
A. Negative sequence current
B. Positive sequence current
C. Zero sequence current
D. None of above
Ans.:C
Q.456 The cause of surge voltage in power system are
A. Lightning
B. Switching operation
C. Faults
D. Any of above
Ans.: D
Q.457 The pressure of SF6 gas in circuit breaker is of the order of
A. 100 mm Hg
B. 1 kg/cm^2
C. 3-5 kg/cm^2
D. 30-50 kg/cm^2
Ans.: C
Q.458 Current chopping phenomenon is associated with
A. Resistance switching
B. Capacitance switching
C. Small inductive current
D. Asymmetrical current
Ans.: C
Q.459 Commissioning tests in relay are carried out to ensure
A. correct relay characteristics
B. that no damage has been done in transit
C. capacity of relay
D. none of above
Ans.: B
Q.460 Wave base transform measures information in
A. Time domain only
B. Frequency domain only
C. Time and frequency domain
D. none of above
Ans.: C
Q.461 Why air-gap between poleshoe and armature kept optimum?
A. To reduce armature material
B. To reduce reluctance of magnetic path
C. To increase resistance of arm winding
D. None of above
Ans.: B
Q.462 At which condition d.c machine gets maximum efficiency?
A. At no load
B. At full load
C. When constant losses become equal to variable loss
D. Both A and B
Ans.: C
Q.463 At which condition d.c series motor should start?
A. At no load
B. At load condition
C. At both A and B
D. None of above
Ans.: B
Q.464 The speed control of d.c motor can be accomplished above the rated speed by
A. Armature control method
B. Field control method
C. Both A and B
D. None of above
Ans.: B
Q.465 The main drawback of brake test of d.c machine
A. The output of motor cannot be measure accordingly
B. Requires identical machines
C. Not accurate
D. Requires large calculation
Ans.: A