240VAC single phase to 208VAC 3 phase

I am looking to power a 10hp 208VAC 3phase motor from a PowerFlex 70 on a 240VAC 1 phase input.

Assuming I buy an oversized drive (Rockwell is recommending 50% over). Are there any other things I should watch out for? Anyone have experience with this that could offer some tips?

Nearly all of our machines to date have been 480VAC in and 480VAC out 3 phase.

Well, a 10HP motor should consume around (10*746W)/0.9eff = 8.3 kW.
8.3Kw at 240Vac = 34.58 amps.

So you're 240Vac supply should be able to handle 35 amps at full load.
Add to that all other electrical rules of your region.

*All calculation are approximated

Please be sure the drive will operate on single phase. Some drives have input phase loss built into them. I'm sure others will quote the technical details but here is my basic layman's approach. The sizing of the drive is because the components are current rated as well as voltage rated. The single phase current on the two operating phases is much greater to make up for the loss of the other phase. Simple rule of thumb is to double the HP or KW size of the drive. Also, please remember that the starting current is much higher than the running load. Most inverters will go into current limiting at peak current, not running current. The motor and drive may stall if peak current is reached prior to reaching running speed. Most times the simplest and best solution is just change the motor to match the power source but it could be a little iffy at 10HP.

The PF70 will work fine on a single phase input. Make sure you understand the term "de- rate" however. 50% de-rate means the VFD is rated for 2x the motor FLA. this is necessary to not only handle the increased current on the diode bridge, but also to increase the
SC bus capacitance because with a single phase input, there is a lot more DC bus ripple. The drive will not shut down on input phase loss, but it may shut down on excess DC bus ripple. Doubling the size it what you do to avoid that.

Other than that, no problem at all, it's done all the time.