Reason for alternator not producing voltage on board ship

Reason for not producing voltage:

• Loss of residual magnetism.
• Failure of Diodes.
• Malfunction of slip rings and brushes.
• Faulty AVR.
• Loss of Excitation.

Producing voltage but not producing full voltage:

• Prime mover RPM is less.
• Loss of residual magnetism.
• Faulty AVR.
• Air gap is too high between starter and rotor winding.
• Short circuit in field coil.
• Decrease in pole strength.