over current

[OahuMechanical]

I have a press unit wth 3 motors and 3 vfds. The control panel is reading over current and press 2 is not working. Its a very old japanese unit, the vfd for press 2 has 3 lights, (power, run, error). Only "power" is displayed on that vfd, no run, no error. When the motor and vfd are disconnected over current is still displayed. Everything else on this units works. Note this motor is controlled via a pot. No wiring diagram. Please help!

 

[waross]

Do you at least have a brand name?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[LionelHutz]

Not enough info to help.

 

[jraef]

If a VFD is indicating over current and it is not running or even forefeet to a motor, it is toast. Thine to replace it. No point in diagnosing it, the cost to repair an old analog drive will exceed the cost of a new digital one. Time to upgrade.

"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> faq731-376

 

[mikekilroy]

if vfd is turned on (enabled/run on) with no motor connected and it says "output short" then it is toast as Jraef says. period. buy a new one. or have that one repaired. what is the brand/model? if there is spindle orient & position feedback of some kind, you may have to buy exact model or have someone who does retrofits of these look at schematics to see if they can replace it with another brand (assuming the present model is obsolete). Post schematic if you want and some of us who do this for a living can give you more details......