Quiz: Electrical Engineering
Exam: DFCCIL
Topic: Alternators
Each question carries 1 mark.
Negative marking: 1/4 mark
Time: 10 Minute
Q1. Which one of the following methods gives voltage regulation higher than the actual value in an alternator?
(a) ZPF method
(b) MMF method
(c) EMF method
(d) ASA method
Q2. At lagging loads, the effect of armature reaction in an alternator is?
(a) Neutralizing
(b) Cross magnetizing
(c) Magnetizing
(d) Demagnetizing
Q3. An integral number of slots per pole is often used in an alternator in order to:
(a) Eliminate harmonics in the waveform
(b) Provide insulation
(c) Permit easy installation of stator coils
(d) Provide easy removal in case of repair
Q4. Salient pole machine has ……
(a) large number of poles
(b) small number of poles
(c) small diameters
(d) long cores
Q5. Damper in a large generator is used to: –
(a) Increase stability
(b) Reduce voltage fluctuation
(c) Reduce frequency fluctuation
(d) All above
Q6. Harmonics present in alternators affect:
(a) Pitch factor
(b) Chording factor
(c) Neither Chording factor nor pitch factor
(d) Chording factor and pitch factor
Q7. Synchronous generator……………………reactive power.
(a) neither generates nor absorbs
(b) absorb
(c) generate and absorb
(d) generate
Q8. Damper windings are provided to:
(a) Prevent hunting in synchronous motors and provide starting torque in generators
(b) Prevent hunting in generators and provide starting torque in synchronous motors
(c) Provide starting torque in synchronous motors and generators
(d) Prevent hunting in both generators and synchronous motors
Q9. In order to eliminate the fifth harmonic voltage waveform, the phase voltage of an alternator, the coil should be pitched by:
(a) 72°
(b) 36°
(c) 15°
(d) 18°
Q10. In an alternator, if α=60⁰, then find the pitch factor:
(a) 0
(b) 1
(c) 0.5
(d) 0.866
SOLUTIONS
