Total Harmonic Distortion

Total Harmonic Distortion (THD) is a measure of how much an electrical signal has been distorted from its original shape. This distortion happens when extra frequencies are added to the original frequency, which can cause problems in electrical devices. THD is usually measured as a percentage, and lower THD values are better because they indicate that the signal is cleaner and more accurate. Essentially, THD is a way to check if an electrical signal is good or bad, and lower THD means better quality power.

 

• "Clean Power" or a "Pure Sine Wave" is considered to be power with a THD or less than 6%.
• Units with THD over 6% can cause sensitive electronics like computers, televisions, and cell phones to fail prematurely. The electrical distortion may cause components to malfunction or operate improperly.
• The Total Harmonic Distortion (THD) of standard portable generators is typically in the range of 9% to 15%, and some generators may produce as much as 30% THD. As the cost of the generator decreases, the THD is more likely to increase.
• All XD, XG, XC, XT-EFI, and GP-EFI models provide power with Less than 6% THD.
• Generac inverter generators produce ≤3% THD, making them ideal for use with sensitive electronics.
• Generators that produce between 6% - 30% THD are NOT recommended for use with sensitive electronics.

Can I improve the THD of my generator?

No, harmonic distortion is determined by factory-installed components and cannot be modified by the end user. 

See also

• What is TruePower™ Technology?
• How does the sine wave produced by a generator relate to total harmonic distortion (THD)?
• Are Generac Home Standby Generators Safe to Power Sensitive Electronics?