It would be really useful to know what else should be disconnected or done beside disconnect the battery .I did some welding on the bucket of my old pc200 a few months ago . lately it has been getting hard to start and now the only way it will start is to put a screwdriver across the terminals on the starter motor.:beatsme
This should get lots of responses on weather or not a computer should be disconnected. Regardless of that I can't think of any engineering reason the batteries should be disconnected. If anything the battery would tend to absorb voltage spikes and moderate any stray voltage. I think if the computer is not disconnected the best thing you could do is leave the batteries connected. And I am not an engineer but I would like some real information from one who actually works with the electronics side of it.
Komatsu 150 said:Regardless of that I can't think of any engineering reason the batteries should be disconnected.Click to expand...my new merc truck has a ton of computers and a nice big sticker on it saying if you are welding to disconnect both terminals but none about disconnecting any computers.i guess the short answer is computers don't explode...
before any welding on a machine, the main ground off the batteries must be disconnected.kobelco also recommends disconnecting the harnesses from the computers on the machine. most models have 2 (c-1 & c-2) some new machines even 3 including the ecu.another option, there is surge protectors that join across the batteries 12, 24 & 36 volt that remove any spike from welding.i know a heavy equipment road welder that swears by ityou can purchase from snap-on tools as well as a company in Quebec supposedly sells a really good unit.with this unit there is no need to disconnect.
If you disconnected the batteries and earthed close to the weld, I'd say that your alternator failure is a coincidence.I'veneverlost an alternator or ECM that can be traced back to welding, and I've done about some fairly heavy duty jobs. Arc-air off and mig welding on grousers, compactor feet, blade skins etc.
I'm with Cmark on this. The diode problem in the alternators is something very common to almost all Japanese designed excavators. Some use a third wire as a signal that the engine is running while others use it as a frequency indicator which is calibrated to the speed of the engine. Alternators like all other man made components wear out. It's not necessarily something someone did to cause it.The Komatsu product has between 16 and 20 diodes in the wiring harness to protect against voltage spikes. The rest of the manufacturers have somewhat less.Going back to the computer issue I'm sure there is little chance of burning a computer when the welder ground is connected next to the place being welded. Putting the ground clamp on the track and welding on the bucket though will cause you grief and possibly not just to the computer. I have seen fry marks on engine crankshafts from just this practice. Given the cost of a computer and all the rest of the components I would suggest at the very least disconnecting the battery. Depending on where I'm welding and what machine I'm working on I would also disconnect the computer as well.
Does your Hitachi Zaxis, have a ground disconect like Komatsu does? If it does I thing as long as Hitachi was not running this was a coincidence. I have never had a problem welding on a machine, and I have made that fatal mistake and i the heat of welding noise and re-positing found that the komatsu, or Case was running. I think removing the ground at least would prevent starting and re-positing. We have so many things going on at the same time it's a real challange. There is also a fuse-able link on Komatsu in case something like the ground disconect doesn't not work.You will know if the disconnect doesn't work the engine will shut off but the rest of the electrical will be on like the control panel. Wack the disconnect with a hammer and it will disconnect. Tea Party 4/15/09
I know that Volvo always recomended that you switch of the master switch when welding, and from B series excavators, E series loaders and the D series ADT which all came out around the same time (2001/2002) that you disconnect all the computers on each machine before welding on any part of the machine!! I have heard some horror storys about Hitachi electrics, I.E blown computers from simple things like jump starting, even heard about one guy who was wiring an air horn type horn horn on a zaxis, earthed it wrong and blew the computer!! Not sure how much i belive that one tho! How ever i know a good auto electricain and will ask him if its posiable to blew a computer from welding!
I'd say your alternator went out on its own. Disconnecting the battery, and keeping the ground clamp nearby where the welding is done is about all you can do. Which is always a good idea.The path of least resistance comes into play. Now with a bad ground clamp connection, and a welding machine that has an earth ground, well, most anything is possibile then. When current starts trying to find its way through your machine trying to find a ground is when it gets bad. The Diode, (more likely the diode trio) in your alternator is a lot tougher than any of the electronics are. Reverse breakdown voltage is often a few hundred volts. Mig machines typically run around 28 volts.Above all do what you feel is right and what the Manufacturer says. But always have a good ground on unpainted, clean metal. People often laugh at me, with my choice of ground clamp, which is a piece of plate bolted to my ground cable, that I will tack weld to what I am welding on. That way I know I have a secure path to ground.All that said, we are talking about welding carbon steel with the SMAW (stick) or GMAW (mig) method. Not high frequency GTAW (tig).I've worked on and around very high end computer automation equipment for years. We always turn off the Power, ground close to where we work.
Before I weld on equipment I allways unhook the battery.The thing that I beleve is most important is allways be directly grounded to the piece you are welding on.For instance ,If you are welding on the excavater bucket,dont clamp the welder ground to the tracks.I was making an extreme example.welding current can damage bering's,cylinders,hydraulic line's etc.
Before welding on the Terex Atlas duck, batteries MUST NOT be disconnected, Earth isolator must be ON, computer connectors must be disconnected ( 6 off) 2 ecu connectors, also connector to night heater must be disconnected, then earth very close to welding point.
I agree with 25c the best you can do is disconnect the neg cable, i had welded all kinds of repairs on machines and never had a problem.
Im not sure what needs to be disconnected, but I can say we were replacing the batteries on a 2000 pete with a C15 Cat , while doing so I guess we touched a terminal to another we shouldnt have because we fried the computer, hauled the truck to Cat to get it fixed , new computer and the truck wouldnt start ,turned out we also fried the starter making it short out inside its self , i dont know how that all happened but it did , needless to say becareful when dealing with electronics and computers
Anybody intending to do any welding work on a newer generation machine definetly needs to be aware of the manufacturers spec before doing so.I always understood to disconnect at minimum the earth terminal but seeing what Terex Atlas state in the manual now leaves me totally bemused ( quite normal then really)
AtlasRob said:...leaves me totally bemused ( quite normal then really)Click to expand...Good one, Rob. I'm glad to see there's someone out there that suffers from the same (quite normal) perplexing dilemmas that vex me more often than is happily desired!Thank goodness for Scotch Whisky. :tong
I would not think it neccessary to disconnect the computer. Disconnect the battery and then clamp both battery leads together. This should prevent a voltage difference across any of the electrical components. As others have said, its important to keep the earth lead close to where you are welding and have nothing vurnerable between the earth and welding point. I think the best precaution though if welding a bucket is to take it off the machine. It's playing safe and probably not neccessary but its a quick, cheap and surefire way of ensuring you do no damage.