In article tswIc.7241$i_3.2328@fed1read04,
says...
Hello All,

I have just aquired a new to me Enco 13" lathe. The lathe itself runs
very well. But my VFD is giving me fits. About every third or fourth
time I turn the lathe on, I get a OC-C fault on my 3hp TECO 100FM VFD.
The lathe has a 3hp 3phase motor. The OC-C fault is supposed to
indicate "Overcurrent during constant speed". The causes indicated in
the manual are 1. Load changes excessively, or 2. Input voltage
fluctuates excessively. The actions are 1. Check load condition 2.
install a reactor between power supply and inverter.

The fault will occur on start up with just the 3 jaw chuck as a load.
It has never occured, once the lathe has reached running speed. I have
increased and decreased the start up time, with no effect on the
problem. The load should be pretty constant. I am not sure what a
"reactor" is.

Do any of you electronics wizards have an idea of what the problem
might be?


Are you running the VFD on single phase input? Have you
measured the line voltage at the inverter's terminals?

Some VFDs can be set to display the voltage of the internal
DC bus. If this unit can display bus voltage it may
indicate, or help rule out, a problem with the supply
voltage. Running the VFD on single phase or low line
voltage could cause the "Input voltage fluctuates
excessively." condition.

You might also look for "current boost" or similarly named
parameter that will allow for short increases in motor
current without tripping the drive.

Ned Simmons