"Jon Elson" wrote in message
...
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

Most VFDs incorporate over current protection for the output transistors. A
large motor
will be seen as a overload and shutdown the output. The inrush current looks
like a short
circuit to the vfd and it shuts down.

Best Regards
Tom.