There are two main reasons to choose an American Rotary phase converter over other options. American Rotary phase converters offer line-to-line voltages that are balanced within 5% and gives full power. This means your equipment runs better and lasts longer than on a static converter which only allows you to get 2/3rds of the power. The second reason to choose a rotary converter from American Rotary is that American Rotary offers a Lifetime warranty on its phase converters compared to a solid state digital converter's 1 year warranty and static's 90 day - 1 year warranty.