Full pitch winding

Half pitch winding

Long chorded winding

Short chorded winding

Limit the current in holding coil

Increase the current in holding coil

Increase the voltage in holding coil

Decrease the voltage in holding coil

Field diverter method

Field tapping method

Armature diverter method

Supply voltage control method

Increase the holding coil current

Decrease the holding coil current

Protect the shunt field from over current

Protect the motor in case of open in shunt field

Maintain rated speed

Maintain motor characteristics

Avoid armature reaction effect

Prevent motor from over loading