Hi,

If I have 300 computors each with a load of 400watts and I want to make provision for UPS back-up, what size UPS do I cater for? I have 3 phase 400VAC available.:rolleyes:

Best bet is to call the manufacturer and work with them. They'd be more qualified to help.

A big part of my job is calling people all day finding prices and tracking materials down. You can find out a lot about how something works if you call their tech department.

Sorry, a UPS is not the way to go. Use a backup generator and a _________ system. Fill in the blank. This seems too much like a homework problem.

Besides watts is the wrong term to use. You should use VA.