I'm not sure how this degraded into a political septic field, but the original poster's question didn't deserve it.
To test a 480v unit on 240 single, is simple, as many of our simple posts identify. I actually run all my 480v VFDs on single phase, from 120 or 240v mains using a dry transformer wired backwards- primary to the source, secondary to the VFD.
To just test to see if it powers up, you can use a 250vA control transformer, just so long as it has a 120/240v secondary and a 240/480 primary... as it was noted above... '4 way'. If you don't have one in your shop, it's time to get one, because it is a veritable 'swiss army knife' for electrical testing and isolation.
Many VFDs will run on single phase... there are some that just won't, and some that're smart enough to complain ("Phase Loss Protection"). There's also some that'll complain, but the fault can be disabled. If you wanna RUN it on single, just make sure that you don't load the VFD over about 50-70%, because the VFD's input rectifiers and capacitors will be under a fair amount of strain... rectifiers from the higher current-per-leg, and capacitors from the ripple.
While capacitor reforming IS a valid concern, I've NEVER been in a circumstance where it was a problem with any of my VFDs... and ALL of MY VFDs were surplus pull-outs that came to me on a pallet, and I paid mebbie ten bucks a piece for 'em. Not a single one got reformed, and the only ones I wasn't able to use, were the ones that were smashed in critical places, or missing desirable pieces....
But if you MUSt reform (and I have done it with many of my antique radios)... just creatively wire the VFD's power supply in series with a common incandescent lightbulb... start with a 3w nightlight, leave it on for an hour or two, then switch to 1 15, then 30, then 50, then 100... then go to full power. It'll either be fine, or it'll die.