Balanced earth fault protection is generally provided in:
- Small size alternators
- Medium size alternators
- Large size alternators
- None of the above
Correct answer: 1. Small size alternators
Balanced earth fault is generally provided for the small size alternators. The reason is that in small-sized alternators, the natural ends of three-phase windings are internally connected to a single terminal. Thus making the use of the Merz-Price circulating principle impossible. For this reason, the earth’s fault-protection is provided for protection against earth faults.