rotary converters are better for high horsepower aps but I have been running an electronic phase converter on my 5 horse mill for about 7 years and still going strong .....just make sure you wire it right and use big enough wire...in and out....it has been so long since I have looked at it that I don't remember what brand it is but I will try to remember to look and let you know the next time I log on. With 7.5 horse you are on the edge of what I would run with an electronic though.