To reduce the copper loss

To increase the residual magnetism

To decrease the residual magnetism

To reduce the reluctance of magnetic path

Cast iron

Soft iron

Aluminium

Rolled Steel

Supplies output continuously

Makes output in the uni direction

Makes output in the opposite direction

Collects the output from alternate conductors

Pulsating voltage

Oscillating voltage

Alternating voltage

Direct current voltage

To increase the flux in air gap

To decrease the magnetizing current

To magnetize the poles to produce coil flux

To increase the reluctance of magnetic path