To get more voltage

To share more loads

To improve efficiency

To maintain constant frequency

Dark and bright lamp method

Ward - leonald method

Over excitation method

Under excitation method

All 3 lamps in dark

All 3 lamps in bright

Two lamps bright and one lamp dark

One lamp bright and two lamps dark

3

6

8

10

Megger

Phase sequence meter

Synchroscope

Centre zero ammeter