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

Soft iron

Cast iron

Cast steel

Stainless steel

Reduce the friction loss

Reduce the windage loss

Reduce the hysteresis loss

Reduce the eddy current loss

Shunt generator

Series generator

Differential compound generator

Cumulative compound generator