Empire

Cotton

Bamboo

Terylene

Ground test

Polarity test

Open circuit test

Short circuit test

Generate maximum flux

Reduce the stray losses

Maintain the rotor speed constant

Produce more uniform rotor field and torque

Iron loss

Copper loss

Friction loss

Windage loss

By rotor rheostat control

By changing applied frequency

By changing the applied voltage

By changing the number of stator poles