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