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

Field control method

Voltage control method

Armature control method

Ward Leonard system of speed control

Regulate the field voltage

Reduce the armature current

Control the armature reaction

Smooth operation of motors

Cotton

Bamboo

Fiber glass

Leatheroid paper