text: <s>[INST] PF 400 Faults Summary: PowerFlex 400 Overcurrent and Ground Fault on Start CommandI have around 60 PowerFlex 400 drives running and most run perfect. On about 20 of the drives, I regularly get either an overcurrent fault, a ground fault, or both as soon as I send a start command. I clear the fault and the drive starts and runs fine. Sometimes the drive will start without faulting. I'm using a 30 second ramp start. Any ideas? [/INST] http://literature.rockwellautomation.com/idc/groups/literature/documents/um/22c-um001_-en-e.pdf Take a look at page 18 of the user's manual link above. It discusses the phase-to-ground jumper for ungrounded systems. You haven't told us what frame sizes you're using or if your system is solidly grounded or not. This might be one source of the problem. It also might be the distance of the motors from the drives - how long are the T-leads from drive to motor? \\n </s>