Welding and Machine Electronics

[Corley5]

I needed to do some welding on the Fabtek and still do  ;)  The computer boxes say to unplug all connections going into them before welding or damage may result.  I unplugged them and then had to reposition the head and had all sorts of error messages.  The plugs are messed up and need new pins but after some screwing around I was able to get things working again.  I still need to do the welding but don't want to unplug the boxes again until I have the new pins for the plugs.  Is disconnecting the battery cables good enough?

[pineywoods]

Corley, I'd say unplug everything going into the computer box before welding. Pulling off the battery cable won't help and may even make things worse. All them cables make an excellent antenna that will pick up induced current and radio frequency emissions generated by the arc . I've seen old fashioned incandescent light bulbs taken out by arc welding nearby, computer stuff is a lot more fragile.

[wildbill]

ive never had a problem with both automotive or industrial electronics and welding.  done both stick and mig in both environments.  however since you can disconnect the computer it is the safest bet.  a few minutes of replacing pins vs. buying a new ecu seems worth the trouble.

[justallan1]

I think I'd do your welding when you have it all disconnected just to be safe. I figure the warning stickers are there for that one time out of a thousand and I may just be that one. It's probably going to cost you an hour at most versus down time and money if something goes bad.

Allan

[DDDfarmer]

My real job is at a hydro-electric site.  One of my co-workers site was under some maintenance and needed some welding done on a bearing pedestal.  Lets just say these newer hydro sites are getting to be wired up the ying-yang.  Vibration, speed, temp, deflection and on and on. 

There was one stray arc.  Costs added up to.......could be a very nice pickup truck.

I would say unplug and isolate all you can.  Your labour is very cheap compared to some of the electronics out there.

[Gary_C]

Check your operators manual for specific machine instructions. It's extremely important to follow all the directions on these machines or you can have big problems.

On my Ponsse harvester, I have to do things in a specific sequence to prevent problems. I've only gone thru the steps once and can't remember all the steps and the order, but they include disconnection the engine connector, disconnect the battery cables and bolt the cables together, turn on the grounding switch, remove the computer, disarm the fire supression system, and turn off the master switch.

The whole process is a real pain but it's very necessary. Some of those computerized circuit boards are so sensitive you can destroy them just by disconnecting then and touching the connectors. Just the static electricity in your body can zap them.

[thenorthman]

I just disconnect the battery... never had a problem except the one time I didn't disconnect the battery and it fried... the battery.

Make sure you have your ground set up in the right direction.  Welding makes a circle from positive to neg,  if you have a neg ground all should be well if you reverse it... who knows... (the only real reason to reverse it is when welding thin material keeps the heat in the filler material and not in the part, even then it don't help a whole lot)

I have welded on cnc machines while they where running with no ill effects, and believe me the computers on them are very fragile and very large, pushing 240v compared to 12-24v

[Jamie_C]

We always unplugged the cables from the computer in the cab when doing any welding and also turn off your main power switch

[bushmechanic]

I would say for you to do whatever you think is right. Personally I have had that much trouble with connectors that I don't unplug them anymore for me it's just not worth the hassle. I don't disconnect the batteries either but in saying that I did purchase two surge protectors from Napa. They come in 12 and 24 volt and they clip on the batteries for welding on equipment with electronics. I keep the ground electrode as close as possible to the weld and have yet to fry any electrical component. Maybe I have good luck but it's really up to the owner on how it gets done.

[1270d]

Between the ecu, PC, head computer and hub Im pretty sure there is over 10k in computers on my machine.  I disconnect all of them when welding.  It takes around ten minutes but seemsworth the extra time.  I have welded with it connected once with no iI'll effect, but won't make a habit out if it.  Unplugging is cheap insurance.   

[Ken]

I had zero experience with machines that had computers prior to buying the harvester.  We did do some minor welding on the machine a number of times before I took the time to thoroughly read through the manual.  We had only been unhooking the batteries.  Now I make sure that all connections are unhooked.  It only takes me 4 or 5 minutes.  Guess I got lucky a few times.

[SPIKER]

...
don't disconnect the batteries either but in saying that I did purchase two surge protectors from Napa. They come in 12 and 24 volt and they clip on the batteries for welding on equipment with electronics. I keep the ground electrode as close as possible to the weld and have yet to fry any electrical component. Maybe I have good luck but it's really up to the owner on how it gets done.

We built a lot of equipment in 12 ~24 VDC with Saure-Danfoss PCs on them.   This was a daily/weekly welding on Brand New machines for re-work or add on items.   I worked there 5 years and I bet we burnt up 50+K in Computers in that 5 years from people NOT disconnecting them prior to welding.   This included things from the SD Computers, to CAT & Cummins ECUs down to Relays and Lights.   One of the worst ones took out the CANBUS system and 9 SD PCs and one of the 2 CAT ECUs.   The 2nd Engine ECU dies a couple weeks into testing...   

We bought some of the ZAP Protectors but no one seemed smart enough to use one...

When welding on the machines always grind off the paint next to spot to be welded on, then clamp the ground there onto the lose part or part farthest away from the battery/Electronics.   I also suggest you disconnect the Battery and the Electronics but if you cant then disconnect both Neg and Pos Battery Cables and short them together to keep the +/- tied while welding.   This should help isolate both the + and the - from getting Zapped.

Mark

[Corley5]

Been gone since yesterday and just got home and read the operators and service manuals.  It says to shut the main switch in the cab off and ground as close as possible to the area to be welded.  Nothing is said in either manual about unplugging the computers at the boxes in the cab.  The stickers on the boxes clearly say to unplug them.  I'm going to and shut off the battery disconnect and unhook and connect the battery cables to themselves for good measure.  This is on the agenda for morning.  Thanks guys  8) 8)

[GRANITEstateMP]

I know from my experience in racing (stockcars) that it's always better to air on the side of caution, we always unhook the MSD (ignition) box(es) and normally remove the battery.  For the time it takes to do it (in a racecar) vs. the possible failure / cost, just seemed like the thing to do.  With that said, it's a heck of a lot easier to for us to do it on a racecar vs. a piece of equipment with multiple systems...

[Corley5]

I unhooked everything, did the welding, hooked everything back up and it all works.  I have to re assemble some more stuff yet and weld on it again Friday