The most serious fault on alternators that requires immediate attention is the stator winding fault.
These faults occur primarily because of the insulation failure of the stator windings. The main types of stator winding faults, in order of importance in ascending order are mentioned below:
- Fault between phase and ground
- Fault between phases
- Inter-turn fault that involve turns of the same phase winding
It is important to note that stator winding faults are most dangerous faults and if these faults are not immediately cleared, they lead to burning of stator coils.