Can a step up transformer designed to step up from 110v to 220v be used to step up from 230v to 460v? (I'm thinking one of those cheap Chinese auto transformers from ebay, in the 1kva-2kva range)
I expect it will tolerate a small over voltage, such as 10% or 20%, but could it do double (or more), or will it overheat pretty much instantly?
The application is to step up single phase to input into a motor VFD to get the most out of it and drive a motor which can't be re-wired from Y to delta to run at 230v. I'm aware that this will only work with a single phase input VFD, or a three phase VFD de-rated appropriately.