3. Stand-alone generator operation

3.1 Regulated constant speed on linear load

This operation (figure 20 ) corresponds to the equivalent single-phase Behn-Eschenburg (smooth poles) or Blondel (salient poles) diagrams, but the operation is quite different in this case, as voltage and frequency are no longer externally imposed. The speed must be adjusted at all times to keep the frequency constant, by acting on the mechanical power of the drive unit. This is particularly the case with emergency generators. This is usually done automatically by means of a speed controller.