Generator Power factor Calculation with varying Output Power
The power and the power factor are both determined by the load characteristics and the response of the load to changing frequency and voltage. The engine speed controls the generator's output voltage and frequency. The engine determines the maximum power. If the generator delivers too much electrical power to the load, it will require more torque than the engine can deliver and overload the engine.
The generator has a maximum safe output voltage and output current. The minimum power factor will mostly be determined by the maximum current. Wound-field synchronous generators have additional limitations determined by the maximum field current limitation and control considerations.