All VFDs are technically capable of being fed with single phase power and running 3 phase motors, it's inherent in the concept of how they function. The thing is, the VFD must be de-rated for two reasons;
1) The diodes on the rectifier side will see more current on fewer diodes (4 instead of 6) because of the difference in current between 3 phase and single phase. Single phase current is higher by the square-root of 3 (1.73x).
2) The rectification process of single phase power will cause more "ripple" in the DC bus, so it needs more capacitance on the DC bus to take care of it, AND the capacitors will run hotter than normal.
So for BOTH of those reasons, most mfrs will require that you over size the VFD by a factor of 2 as a MINIMUM. So look at the FLA of the 3 phase motor, double it, then select a VFD that is rated for AT LEAST that many amps. The quick and dirty way is to just double the HP rating, so for a 7-1/2HP motor you buy a 15HP drive. You ALSO have to be aware of the heating issue and cut the ambient temperature rating by 1/3, so if a VFD is rated for 40C (104F) operation, it can't handle more than 25C (77F) ambient, or you can de-rate it a little more, so a 20HP drive for a 7-1/2HP motor. Many people don't bother with that second de-rate and take their chances here, because for the most part, these machine tools aren't run continuously.
Smaller drives, up to 3HP at 240V, are sometimes available for single phase input without de-rating, simply because at those small sizes the difference in cost of the larger components becomes insignificant so they just throw them in that way. That's becoming less common however because prices have dropped and margins are tighter for the drive mfrs. So now they sell a drive that looks the same and uses the same case, so the physical size remains the same, but the part numbers are different because the 3 phase versions are using smaller power devices. But no matter what, above 3 HP you must at least double the size of the VFD relative to the motor current. There are a couple of people, like Polyspede and AC Tech, that sell/sold larger drives rated for single phase, but if you compare prices you discover that it's just a marketing trick in that they are the same cost as just buying the 2X drive and de-rating it. They just do it for you on the nameplate.
The "gotcha" to the 2x program however is that a FEW brands of VFD do not allow you to do this, simply because they have Phase Loss protection and they don't give you a way to disable it. The drive COULD work, but they don't let you do it. So you have to RTFM before you buy it to make sure. That used to be more common but lately more and more of the VFD mfrs have figured out that they were missing out on a market segment.
