Significance

• A generator's output frequency is based exclusively on the number of revolutions per minute of the engine and the number of magnetic poles in the engine. Standard designs use two or four magnetic poles surrounding the rotor.
  
  

Considerations

• Many generators feature meters on their control panel that will give you a direct reading of the rpm your motor is operating at. If this is not the case, however, you can use a multimeter capable of measuring Hertz attached to the output wire from your generator to determine the frequency yourself.
  
  

Formula

• Determine the rpm of your generator's rotor, and multiply this number by the number of magnetic poles it uses. Divide the result by 120 to find the frequency of the generator in hertz, the standard unit of electric frequency.