Hi.

Can someone explain how a generator power factor can be altered? For example if a diesel generator has the ability to be set to operate with a power factor between 0.8 lagging to unity. What exactly is done to the generator to alter the power factor at which it operates?

Thanks

 

Power factor of a system is determined by the load on the system(inductive , capacitive). The power factor at the alternator is controlled by the excitation of the alternator field current ie by increasing or decreasing the field current to over or under excite the field. This causes the alternator to "export" or "import" VARS(reactive power) and helps to maintain power factor of a whole system at a desired level usually about 0.85 to 0.9 lagging.