Adjusting the speed of the prime mover of an alternator is primary necessary. Which one of the following is the reason for this ?

To get constant frequency

To get constant voltage

To get increase polarity

None of the above

To increase stability

To increase output

To decrease output

To reduce voltage fluctuation

1800 rpm

1200 rpm

1000 rpm

600 rpm

rotating alternator

rotating field with a smooth cylindrical rotor

rotating field with a salient pole rotor

rotating armature with field

2 slip rings

3 slip rings

4 slip rings

6 slip rings