Just like a 1N200X diode...
Hee hee... "Inverter-Duty"... "Enhanced Testing"...
Yeah, just like the 1N200X series diodes... All parts made the same, the ones given a 1N2007 simply passed the 1kv test... while the lower specs (1N2004, etc) leaked at lower PRVs... otherwise, same dude.
Well, totally avoiding the scientifics- I took my '58 BRJ mill, and cut the 3-phase plug off. Wired it direct to an Allen-Bradley AA08A (bulletin 1305?)'s A_B_C terminals, hooked in a 20K pot, a direction/stop switch, and two 100-ohm 500w wirewound resistors (to the DB terminals, and have been running it on single-phase 240v (L1, L2) for the last eight months. I put the motor belt on center sheave (so the sheaves are closest to equal sizes) and haven't done anything but cut metal since.
Works great, hasn't smoked.
Only think I'd really be concerned about (in terms of using a non-such-rated 'inverter' type... is running it slow and not having it provide itself with enough cooling airflow. In that case, rip out the original fan, and put a decent-flow 'muffin' type fan on the housing, make a suitable shroud to direct cooling air into the motor.
Also note, and I'm not certain how much it really matters... Bridgeport used to heavily advertise it's method of machine cooling... motor cooling air went through the head in many places to keep the various drive segments cool. Perhaps it mattered, and perhaps it only mattered when trying to split ten-thousanths... I don't know, but be aware of it anyway.