hello,
has anyone had the big semiconductor fuses blow on a system 12? we've been blowing the 400A fuse intermittently. There has been times where 5 out of the 6 are blown.
From what i have gathered it happens when the car is in motion and it clips a door lock. regardless of speed I've seen it on high speed and while leveling into floor.
After fuse is replaced, and doors are working properly car will run fine. Does anyone have any input on where to start looking?
The setup is an icontrol/ibox with a haughton machine

In general, those Amp Traps are extremely sensitive and should all be replaced when any of them go. It could be that you have been chasing around weakened fuses. If it was only at high speed I would suggest making sure the fields are weakening enough to keep armature current at nameplate. I had similar problems on a System 12 drive that ended up being a weak original equipment breaker that was left in the system before the disconnect. I would go through all the connections from the disconnect through the isolation transformer. A good thermal imaging camera is an excellent tool for this kind of problem. Maybe a bad contact in one of the contactors. It would show up quite a bit hotter than the others.

Car needs to set up by the book. Are the overloads set up properly on the drive? Is the voltage at the bottom of drive at least what the armature is rated for? Are the drives offsets setup correctly? Also how about the motor field voltage? What controller IMC or Ibox?

When car is setup your supposed to pull door lock wire while setting up to adjust certain settings to prevent this type of stuff. My bet is that the overcurrent is maxed out along with other settings.