You cannot run a single phase motor on a 3ph VFD, There are 1ph VFD's out there for 1ph motors that are cap-start-cap-run (no centrifugal switch) but they are very unreliable and tend to drop out of control as soon as rpm drops too low.
The reason for de-rating a VFD when hooked into 1ph is that the DC supply has less capacity on 1ph than 3ph, the AC input is rectified filtered and then converted to variable 3ph out. If you dont intend running your 3ph motor up to maximum current then you can get away without derating.
Also usually the reason for faulting out when using fast accel. decel rates is overvoltage not overcurrent due to the regenerative action caused by rapid braking.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.