Robert Swinney wrote:
Under-powered VFDs cannot cope with the starting surge demands of a "too" large motor.
It is not the starting surge, it is the line current. The line current
of most motors doesn't change much from no-load to full load. What
changes is the angle between voltage and current. So, an undersize VFD
can't supply the line current the motor draws, even at no-load.

Jon