Alternator MCQ | Synchronous Generator MCQ

111. If the rotor emf per phase at standstüll is E₂ and the motor is operating at a slip (s), the generated rotor emf per phase under running condition will be

1. s²E₂
2. E₂
3. sE₂
4. E₂/s

112. The distribution or winding factor is defined in an alternator in terms of

1. Power factor
2. Electromotive force
3. Power
4. Current

113. The speed of two pole alternator at 60 Hz is

1. 3600 rpm
2. 750 rpm
3. 300 rpm
4. 1500 rpm

114. What is the frequency of voltage generated by an alternator having 6-poles and rotating at 900 rpm?

1. 50 Hz
2. 50 rad/s
3. 45 rad/s
4. 45 Hz

115. Alternators are constructed with

1. Rotating armature and rotating field
2. Stationary armature and rotating field
3. Rotating armature and stationary field
4. Stationary armature and stationary field

116. A synchronous generator is feeding a zero power factor (lagging) load at rated current. The armature reaction is

1. Magnetizing
2. Demagnetizing
3. Cross-magnetizıng
4. Ineffective

117. The armature reaction effect in a synchronous machine depends on

1. Load current
2. Power factor of the load
3. Speed of the machine
4. Both load current and power factor of the load

118. How can the reactive power delivered by the synchronous generator to be controlled?

1. By changing the prime mover input
2. By changing the excitation
3. By changing the direction of rotation
4. By changing the prime mover speed

119. The stator winding of an alternator is normally connected in star to eliminate the ________ harmonic component of the voltage waveform.

1. Third
2. Fifth
3. Seventh
4. None of these

120. In a synchronous generator, a divided winding rotor is preferable to a conventional winding rotor because of

1. Higher efficiency
2. Increased steady-state stability limit
3. Higher short circuit ratio
4. Better damping