Which of the following statements is NOT correct about the significance of stationary armature alternator?

Question

Question

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SSC JE Electrical 9 Oct 2023 Shift 3 Official Paper-I

The output current can be easily taken from rotor winding.
The armature windings of the rotating field alternator are not subjected to centrifugal forces.
The armature windings can be braced better mechanically against the high electromagnetic force.
The rotating field type alternator has a smaller size than the rotating armature type.

Answer 1

The correct answer is option 1.

Construction of alternator

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The main components of an alternator or synchronous generator are rotor and stator. The rotor is a rotating part and the stator is a stationary part.

In alternators, the field winding is placed on the rotor whereas the armature winding is placed on the stator.

Reasons for placing field winding on the rotor, not on the stator:

The output current can be led directly from fixed terminals on the stator (or armature windings) to the load circuit, without having to pass it through brush-contacts.
Armature winding deals with the high levels of voltages, hence it is easier to insulate a stationary winding as compared to rotating winding.
The stationary 3-phase armature can be directly connected to the load without going through large, unreliable slip rings and brushes.
Only two slip rings are required for DC supply to the field winding on the rotor. Since the exciting current is small, the slip rings and brush gear required are of light construction.
Due to the simple and robust construction of the rotor, a higher speed of rotating DC field is possible. This increases the output obtainable for a machine of a given size.
For large-rating alternators, the construction of the armature on the rotor becomes more complex.