John,
To quote HopefulDave:
.....older inverters (ABB ACS300 series, for example) have two banks of reservoir capacitors, a little rewiring to put the neutral between the banks and live to two of the rectifier's three phase inputs and it thinks it has 480v in when you feed it 240... Again, derating by about a third is in order!
So, no undervoltage problems.
When I modded mine I ran it up via a Variac and an internal relay clicked in at 190v input.
Phil.