Question

Explain the working of a single-phase AC generator with necessary diagram.

Answer 1

1. The loop PQRS is stationary and perpendicular to a plane, when field windings are excited, magnetic field is produced around it.
2. Let field magnet be rotated in a clockwise direction. Assume initial position is horizontal, the direction of a magnetic field is perpendicular to plane of loop PQRS Induced emf is zero. It is represented by O in the graph.
3. When rotates to 90°, a magnetic field is parallel to PQRS, an induced emf becomes maximum. Direction of induced emf is given by Flemming’s right-hand rule.
   
   The loop PQRS and field magnet in its initial position
   
   Variation of induced emf with respect to time angle
4. When rotates to 180°, field is perpendicular to PQRS, an induced emf is zero. It is represented by point B.
5. When rotates to 270°, field is parallel to PQRS, an induced emf is maximum but in a reverse direction.
6. Current flows in SRQP. It is represented by point C.
7. On completion of 360°, field is perpendicular to PQRS, an induced emf is zero and noted by point D.
8. When field magenets complete one rotation, induced emf in PQRS finishes one cycle.
9. Frequency depends on the speed of field magnet rotates.