Electrical Engineering questions and answers for competitive exams published here which help the Electrical Engineering candidates going to attend the upcoming Recruitment Examination for the post of Junior Electrical Engieer, Electrical Engineer, Electrical Project Manager, Electrical Engineering Project Head etc.
Question No. 1. The range of efficiency for shaded pole motors is
(a) 5% to 35%
(b) 80% to 90%
(c) 50% to 75%
(d) 95% to 99%
(A) double frequency currents in the rotor
(B) healing of rotor
(C) vibrations
(D) all of the above.
(a) 5% to 35%
(b) 80% to 90%
(c) 50% to 75%
(d) 95% to 99%
Answer: (a) 5% to 35%
Question No. 2. Unbalanced 3-phase stator currents cause
(A) double frequency currents in the rotor
(B) healing of rotor
(C) vibrations
(D) all of the above.
Answer: (D) all of the above.
Answer: (b) it has low starting as well as running currents at relatively high power factor
Question No. 6 . The Potier's triangle separates
(A) stator losses and rotor losses
(B) fixed losses and variable losses
(C) armature voltage and field voltage
Answer: (D) armature leakage reactance and armature reaction mmf.
Question No. 7. It is advisable to avoid line starting of induction motor and use starter because
(a) it will run in reverse direction
(b) it will pick up very high speed and may go out of step
(c) motor takes five to seven times its fullload current
(d) starting torque is very high
Question No. 3. An important advantage of a synchronous motor over wound round induction motor
is that
(a) its power factor may be varied at will
(b) its speed is independent of supply frequency
(c) its speed may be controlled more easily
(d) none of the above
Answer: (a) its power factor may be varied at will
Question No. 4. Pitch factor is the ratio of the emfs of
(A) short pitch coil to full pitch coil
(B) full pitch winding to concentrated winding
(C) full pitch winding to short pitch winding
(D) distributed winding to full pitch winding.
is that
(a) its power factor may be varied at will
(b) its speed is independent of supply frequency
(c) its speed may be controlled more easily
(d) none of the above
Answer: (a) its power factor may be varied at will
Question No. 4. Pitch factor is the ratio of the emfs of
(A) short pitch coil to full pitch coil
(B) full pitch winding to concentrated winding
(C) full pitch winding to short pitch winding
(D) distributed winding to full pitch winding.
Answer: (A) short pitch coil to full pitch coil
Question No. 5. Two-value capacitor motor finds increased application as compressor motor in small
home air-conditioners
because
(a) it is comparatively cheaper
(b) it has low starting as well as running currents at relatively high power factor
Question No. 5. Two-value capacitor motor finds increased application as compressor motor in small
home air-conditioners
because
(a) it is comparatively cheaper
(b) it has low starting as well as running currents at relatively high power factor
(c) it has almost non-destructible capacitor
(d) it is quiet in operation
(d) it is quiet in operation
Answer: (b) it has low starting as well as running currents at relatively high power factor
Question No. 6 . The Potier's triangle separates
(A) stator losses and rotor losses
(B) fixed losses and variable losses
(C) armature voltage and field voltage
Answer: (D) armature leakage reactance and armature reaction mmf.
Question No. 7. It is advisable to avoid line starting of induction motor and use starter because
(a) it will run in reverse direction
(b) it will pick up very high speed and may go out of step
(c) motor takes five to seven times its fullload current
(d) starting torque is very high
Answer: (c) motor takes five to seven times its fullload current
Question No. 8. Two alternators are running in parallel. If the field of one of the alternator is adjusted, it will
(A) reduce its speed
(B) change its load
(C) change its power factor
(D) change its frequency.
Question No. 8. Two alternators are running in parallel. If the field of one of the alternator is adjusted, it will
(A) reduce its speed
(B) change its load
(C) change its power factor
(D) change its frequency.
Answer:(C) change its power factor
Question No. 9. Flywheel is used with D.C. compound motor to reduce the peak demand by the motor,
compound motor will have
to be
(a) cumulatively compounded
compound motor will have
to be
(a) cumulatively compounded
(b) under compounded
(c) level compounded
(d) differentially compounded
(c) level compounded
(d) differentially compounded
Answer: (a) cumulatively compounded
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