Produce high voltage to initiate the rotation
Produce high current to start rotate the motor
Produces torque and runs near in synchronous speed
Produce a high magnetic-field to maintain a constant speed
Insufficient excitation
Defective pony motor
Open in damper winding
Short in damper
Varying the motor load
Varying the rotor excitation
Varying stator voltage in motor
Varying stator current in motor
Maintain power factor
Excite the field winding
Maintain constant speed
Start the synchronous motor
SCR converter
Rotary converter
Motor generator set
Mercury arc rectifier