Dead VFD

A friend of mine has a Motortronics series KP1-210 inverter on a lathe
conversion (in his home shop) and the inverter has gone 'toes up' indicating
a 'Transistor Fault'.

First question: Does anyone have access to a schematic of this unit? He has
contacted the manufacturer but they said that they don't have schematics for
out-of-production units (hard to believe they threw out EVERY copy!).

Upon preliminary examination it looks like one of the sections of the
'output module' (potted module bolted to the large heat sink and directly
connected to the motor terminals) is shorted. I have not studied the module
yet but isn't this likely to be something like two FETs connecting the motor
lead to either power rail?

My thinking is that I could replace the bad section with a suitable power
FET module to get him up and running again but I wonder if I should replace
all three sections so that they are matched?

The unit is rated at (front panel label):

Input: 200-240 Volts, 3-phase
Output: 200-240 Volts, 3-phase, 13.9 KVA, 35 Amps

He is using it in 'derated' mode, feeding it with single phase 230 volts and
driving a 7.5, 208 3-phase volt motor.

Is it possible that he blew it because he's using 230 V to drive a 208 V
motor? He hadn't told me until yesterday about the 230 .vs. 208 issue.
Could he be trying to drive a motor wired in 'Y' configuration? (I'm over
my head on 'Y' .vs. Delta other than knowing that they are different) Is
this doable?

If I can replace the output module, can anyone suggest a rating, model,
supplier?

Cheers,

Chuck Hackett
"Good judgment comes from experience, experience comes from bad judgment"
7.5" gauge Union Pacific Northern (4-8-4) 844