AC voltage follows a sine wave. A perfect sine wave is shown below on the left. The position of the winding groups and other factors in the generator end determines the generator’s output voltage sine wave. Since the generator end is not prefect there are variations in a mechanically produced since wave from “perfect.” This variation is called Total Harmonic Distortion or THD.
Perfect Sine Wave
Variant Sine Wave
The diagrams above show a perfect sine wave (left) without any THD, and a sine wave with variations (right). All of Winco’s current product offering has THD of less than 6%. This is suitable for most applications.