How to Measure Output on a Portable Generator

Portable generators are useful power sources at times when you don't have access to the traditional power grid. They're commonly used to supply household electricity in a power outage and to power up construction sites and recreational vehicles.



Generator manufacturers provide the power ratings for each unit. But if you want to know the "actual use" power output of your machine, you can measure it yourself. The power output of a generator is expressed in terms of watts. To determine the watts produced by your generator, you must multiply the current by the voltage. To ensure that the resulting number is correct, make sure your current reading is in terms of amps and your voltage reading is in volts.

Things You'll Need

• Digital multimeter

Show More

Instructions

• 1

  Set up the generator in a well-ventilated spot.

• 2

  Start the generator and let it settle down to a steady speed.

• 3

  Put your multimeter on the "AC volts" setting. Choose the correct range setting for measuring in the range of 120 volts.

• 4

  Touch the two multimeter leads to the positive and negative terminals of your generator's AC outlet. The voltage reading will appear on the digital display.

• 5

  Write down the voltage reading in volts.

• 6

  Remove the leads from the generator.

• 7

  Set up your multimeter to read amps in the range of your generator's specified current output. This usually means plugging the leads into different terminals on the multimeter: the black lead to the common terminal labeled "COM," and the red lead to the terminal designated for the high current range.

• 8

  Measure the current output in amps.

• 9

  Write down the current reading.

• 10

  Multiply the voltage reading by the current reading. The result is the power output of your generator in watts.