[rebrumm]

the brand new mill i use at work with less than 80 hours on it suddenly quit working. i took a look at the VFD and it was showing an EF3 error code . i looked in the book and found this means a simultanous forward and reverse signals to the drive. i removed the panal on the control pendant and removed both fwd and rev wires from their switch effectivly opening both. the VFD continues to display EF3 and won't reset. any ideas?

thanks
russ

[Mike Nash]

Well actually, EF3 is an External Fault which means Terminal S3 is either on when it should be off, or vice versa depending on the setting of n052. The default is for n052=3 wich is External Fault N.O. meaning the drive will fault with EF3 displayed if the input to terminal 3 is ON. On could be 24V or 0V depending on the setting of switch SW1 (PNP or NPN). If N052 is set to 0 it implies the drive was setup for 3 wire control with Start and Stop pushbuttons and S3 is the Reverse direction selector switch input in which case you shouldn't have an EF3 showing up.

Good Luck, this one should be pretty easy to find.
Mike Nash

[rebrumm]

Mike.. i have been thinking about your post for the best part of an hour. the pendant has a DPDT center off panal switch. S1 goes to the fwd side, S2 to rev with a jumpered common out going to a NC E-STOP connected to S3. what confuses me is.. it would appear to me that S3 would have a continous signal untill either the fwd/rev was centered or the E-STOP was hit. since the mill did stop for a tool change and never worked again i don't understand what could have happened.

the pendant has only fwd/rev, E-STOP, speed pot and coolant pump controls.

thanks

russ brumm

[Mike Nash]

Sorry to take so long. I saw a post about Google SketchUp and thought I would give it a try. Not Bad.

I would suspect n052 should be programmed for Fast Stop N.C. which would be n052=21 if E-Stop is connected to S3. It might be possible it was set to 4 for External Fault N.C. but that would require a reset after an E-Stop was pressed. There are plenty of possibilites, but these drives tend to be very reliable. Does the E-Stop normally require a reset? If so, I would suspect the E-stop switch itself or any other associated switches in series with it. You can check S3 with a meter or use u-06 to see what the drive reports. You'll need the manual to understand u-06. See page 4-3.

The manual is available as a PDF here:
http://www.yaskawa.com/site/dmdrive.nsf/link2_NewWindow/MNEN-5JLRKP/$file/TM.V7.01.pdf?OpenElement

If that is link is busted, search for TM.V7.01.pdf at http://www.yaskawa.com

Mike Nash

[rebrumm]

thanks mike for your help
after reading you posts and reading the manual i found the problem in less than 5 minutes. when i first looked inside the pendant i failed to notice a pair of wires connected in parallel across the E-Stop. i followed the cable to an external microswitch mounted near the manual spindle brake arm. for whatever reason the switch had closed. this is odd since the manual brake has never been used because of the dynamic braking from the drive works very well. this switch has to be a retrofit by the dealer where we bought 4 of the mills (Atrump 3's) because of the poor placment. anyway it works now

thanks again
russ brumm Clairton PA