Virtual Frequency Drives

We have a 3-bay PDQ laser wash, starting its 4th year of operation. This past month all 3 of our 15HP AC-Tech VFDs within our G5 pump stations failed within 3 weeks of eachother. Has anyone else encountered this problem? We are past the warranty period, so we were out of luck with no-cost replacements.

Many failures I have seen where caused from power feed issues ie a week 3rd leg or a wild leg. A VFD will run on 2 legs for a while but seem to wear out the units after a while. Also if they get over-voltage on one leg from time to time they don't like that to well and fail. So what I am saying is watch for voltage problems. What type of voltage service do you have at your location? You may need a buck boost installed.

You can buy fault detectors that shut down if a leg is lost.
I got one off ebay

I think you mean VARIABLE, not virtual.

Your right, I meant to say Variable.