WorksheetsAlternator Quiz
Total questions: 10
Worksheet time: 5mins
When the speed of an alternator increases
The frequency decrease
The frequency increases
The frequency remains same
The frequency changes
In alternators the standard practice, now a days is to have
Rotating field
Rotating armature
Both A & B
Static Field
In an alternator, the armature reaction will be completely magnetizing in case the load power factor is
Zero lagging
Zero leading
0.866
Unity
In an alternator the voltage generated per phase is proportional to
Number of turns in coil
stator current
rotor current
stator resistance
An alternator is capable of delivering power at a particular efficiency. The frequency can be increased by
Reversing the armature rotation
Reversing the field polarity
Increasing the current supplied to the field electromagnets
Increasing the armature speed
In an alternator the armature reaction is mainly influenced by
The power factor of the load
Short-circuit ratio
Speed of the alternator
Total current drawn
Regulation of an alternator supplying resistive or inductive load is
Always negative
Always positive
Both Positive and Negative
zero
In an alternator short pitch coils are used
To reduce the stray losses
To reduce the size of the machine
To provide accurate phase difference of 1200 between
To reduce the harmonics in generated e.m.f.
In an alternator terminal voltage rise will be more
When leading load is thrown off
When lagging load is thrown off
When unity power factor load is thrown off
No change in load
If the input to the prime mover of an alternator is kept constant but the excitation is increased, then
kVA will be lagging
>kVA will be leading
>kVA will be changed
The power factor of the load remains constant
