Mobile welding using car alternator.

[blue lump brian]

I stumbled across a thread from about 5 years ago, where I think it was Hugh F suggested using a 90 Amp Bosch alternator as a welding generator- I presume one of these:

http://www.ebay.co.uk/itm/Saab-9000-Bosch-0123320039-Alternator-45-90-amp-1994-98-/380152601232?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item5882dc5a90

This could be just what I'm looking for, to patch up my Land Rover chassis. Has anyone had a lot of success on thin material with this setup?

 

[piman]

Hello Brian,

I haven't heard of this but it sounds very unlikely, I assume you are talking about using arc welding rods, and I doubt if they would strike and sustain an arc using a car generator?

Alec

 

[rtbcomp]

You remove/modify the regulator so it gives a higher open circuit voltage.

 

[asmeix6g]

i was at a trade fair a few years ago, some company will kit your van out for you, their welder runs off an alternator.... they were inviting people up to use it... i was one of those people... it was awful! truly awful! i didnt rate it at all! it was the worst thing iv ever attempted to weld with! IMHO - dont bother with it and bear in mind that was a professional company that had obviously done the best they could!

 

[shenion]

I made a portable using a 200A Motorcraft alternator, .

Worked well on stick with just a big rheostat on the field, an output filter cap and a reactor coil. Ran at about 70V OCV spinning at 5k RPM.

MIG requires a regulator to control the voltage. For a good setup, you need a good reactor and filter caps, neither are cheap (nor is a good alternator that can output a higher voltage.)

 

[nickk]

i knew a man who had one on a transit years ago-kept wearing out alternators 'cos the belt had to be overtight to combat slipping.

 

[welditifyoucan1]

I stumbled across an article about some chap in the States who makes tig welders using alternators. He extensively altered the control methods and even included an hf circuit. He says it worked!

 

[dannyp]

an alternator has the potential to work very well.

the bosch alternators can make some serious ocv if the regulators malfunction, main problem is voltage drop off vs loa as the winding will saturate, you need an altornaor off a wagon that has a 24v output in unmodifyed state and good for about 200 A

 

[blue lump brian]

Thanks for all the replies so far. A little bit of context-I'm looking at options for vehicle patching under less than ideal conditions- I don't even have a driveway, and any work I do has to be by a busy roadside. I usually manage -eventually- with the spanner work, but welding is where I'm snookered- I'm looking for ways to take an off-grid welding operation to any quiet spot. Gas would be one solution, but generator-friendly MIG or TIG would be better. Question- what *are* the voltage and current demands of an arc for material up to 2mm? What are the voltage, current, and stability demands of a generator? Do you stabilise the arc voltage or current? Thanks for any help.

 

[R Kraft]

Most mig welding voltages start at about 15v for about 25a.
2mm would be about 80a at 18v.
24v would be about 200a.
For mig, you would need to stabilize the voltage.
Robert

 

[shenion]

For arc, you stabilize the current (constant current). Most are 24v or so with a no load voltage of 50V or more.

 

[Ed.]

There is this one on E-bay, was thinking about putting one in my 4WD but it is way too pricey for what I wanted.

http://www.ebay.com.au/itm/Onboard-...30006690120?pt=BI_Welders&hash=item358d779148

Have no idea if it is any good.

Regards

Ed.

 

[KemppiFrog]

Saw an article in the Mother Earth News (US mag for back to nature types) running an altenator off a Briggs & Stratton Lawn mower. Think it was 24v and they got it to do some rough stick welding. There was some mucking about with the voltage regulator. Better than nothing, but not what you want. Probably a 5000w cheapy 230v genset (B&Q) running a low amp MIG would do for car stuff.
KF

 

[shenion]

There are several. Here's a real old one using an aircraft generator on a car:

http://www.green-trust.org/junkyardprojects/FreeWelderPlans/AutoArcWelder.pdf

Also one using old microwave transformers:

http://www.dansworkshop.com/2008/03/homebuilt-arc-welder/

Also, the Amptramp group on Yahoo is for home built alternator welders. The owner of the group built one using 5 alternators running off a diesel engine. A huge beast that cranks out over 300 amps.