I wish 3 phase was available

is the only benefit of a three phase mig that you can attain higher amp settings?

Or is there some other voodoo at work?

No, all the decent MIG/TIG units on eBay are 3-phase only.

Have found some decent units 2-phase. Seem they are all in California, 2100-mile shipping is over $670. No longer a bargain.

Tim said:

is the only benefit of a three phase mig that you can attain higher amp settings?

Or is there some other voodoo at work?

Click to expand...

3 phase are usually smoother because there's less rectification required to get true dc.

Thia page explains it much better than I can

http://www.allaboutcircuits.com/vol_3/chpt_3/4.html

Si

It's well worth checking out the spec on the welders you see on eBay - Miller and Lincoln have pdfs for the old machines. Many are 2 phase but can be described as 3 phase as they run off 2 of the three phases. Some of them have jumpers at the back that can be changes for different voltages. I'm running the mother of all Millers off a 240V single phase supply. There was a choice of 208V, 380V and 415V and I chose the 208V setting - seems happy.

As simon says, the 3ph units are significantly smoother to use.

Problem is many are 440/575v/3 phase.

Those 3 on ebay are about 5 miles away. I have asked if I can come look at them to see if I can rewire for single phase.

Problem is most are from sellers that buy out equip from some production plant that closes. They know little about them.

Most newer ones have a lot of options. Most are older and hard to find any info on them.

If one of those 3 are usable, I might just get them all, sell the ones that cant be used on single phase.

I know the miller is 3-phase only (miller has all manuals online)

Lincoln site is no help.

Seller emailed back, the Airco 300amp AC/DC Heliwelder will work on single phase.

Current price is $250 for all 3. Will bid, If I get them, will sell other 2. Maybe come out ahead

Good luck Shenion. Sounds like you could be onto a winner.
Si

OMG! I got them for $260.00

So I get a nice big TIG unit and can probably sell the other 2 for close to $1k ea (they sell for that price all the time.)

Time to hitch up the trailer

Well done - that's amazing value just for the TIG - paid the equivalent of $1200 for mine on eBay.

It'll be extra cool if selling the other two pay for it and some extra. Is this tour first TIG? You'll love it.

Yes, my first TIG. Can't wait for seller to give address so I can go get it (about 5 miles away.)

The other two sell routinely for over $1k each. Will do a PROPER listing with info, model #s serial #s, lots of picts etc for each of the other two. I will offer to take units to truck ship dropoff to save shipping. I CANT LOSE .

This is case a sloppy listing with little info and a cryptic title caused seller to lose big time. His loss, my gain.

Edit: He is 6.9 miles away, will pick up thursday morning. Now need to make room in the garage.

Congrats!!!

I just had a similar situation, £162 for a complete running (ok, almost) 3.9 v8 Range Rover, listed in the spares section.

Similar nick regularly fetch £500, i pick it up this weekend.

Well done Shenion. You'll have to let us know what they're like, and how much you make by listing them properly! (we won't tell the IRS)

Si

My EBay haul



Well, picked them up. Some surprises and disappointments. Was probably 1400 lbs of stuff I have to unload. Sooo glad no one cut me off driving back. Definitely felt the weight trying to stop. It hauled it real nice, trailer has been great,

1. There was a box in front of the Airco in the ebay picture. I figured it was a water cooler or HF start for the TIG. Turns out it is a beat up wire feeder (half of case is broken off.) There is a Tweco gun attached.
2. No TIG gun (there is a hand drawing on the front of the Airco showing TIG gas connections.) But i get the feeling they don't know the difference between MIG and TIG.
3. There is a beat up, corroded spool gun included with cover missing.
4. Some of this stuff may have been outside in the rain (spool gun). Maybe not, this was some auto repair place with open bays. Probably was near door. Just the humidity in the summer here would cause the corrosion.

I spent some time online looking for manuals. The airco is not online (have to buy them.)

The Lincoln is a R3S-325. 325 amps! But it is 3 phase. I looked at the schematic and I think I can rewire it for single phase (2 phase). Theoretically I should be able to get 216 amps with this setup. I doubt I will ever need more than 180A. It has a LN-7 wire feed with a Tweco #4 gun. Looks real heavy duty, would be a real pain in tight places. If I can't modify it safely for single phase, will sell it. Otherwise, will be a nice setup. Can sell my Clarke and pay for all 3 Although, it would be nice to have something a bit portable.

The Miller looks good. It is a 330A peak, 250A rated unit (200A at 100% duty cycle.) 3-phase. Will sell this one. There are 3 on ebay at $300-$500 right now.

The Airco 300 AC/DC Heliwelder was the one I was interested in. It is a single-phase beast. Thought it would get me into TIG real cheap. Now, not so sure. I would think I would need a HF start unit and of course a torch. Don't think unit has any scratch start.

Another option is to see if I can use the Lincoln wire feed on the Airco. This is what confuses me. The Lincoln and Airco are basically arc welders. I thought arc was constant current. MIG is constant voltage. But the Miller is definitely a CV unit and was set up for arc welding.

Well, now to get my engine hoist out and try to make room for these.

is the miller a mig?

Haze said:

is the miller a mig?

Click to expand...

It was used as both a MIG and arc welder. The Arco wire feed was hooked up to the Miller. There was also arc cables with it.

The Arco looks like they stopped using it. I think this thing weights 750 lbs. After finally wrangling my engine hoist and put in center of garage, I looked it over.

I did not see anything burnt inside. Real old-school tech. Saw some selenium rectifiers in the top 4 MASSIVE transformers, big fan, lots of power resistors.

Jeez, this thing says 5 to 465 amps!

There are two capacitors in the high-frequency circuit that have oozed goo. That answers my other question, yes it does have HF start. I do not see anything else that looks burned. Probably the capacitors failed, TIG would not arc, so they abandoned it and bought the Miller to run the MIG wire feed.

They should keep you out of mischief for a while Shenion!

Si, these are 220V 300+amp beasts. Should be able to get me into a lot of trouble

Ok, preliminary results:

The Airco wire feeder works even though half the case is broken off (the cover and the end of the front panel.) It feeds real smooth even with the old 15' cable..

The Lincoln wire feeder works. It is set up for 0.045 wire, so I can't test welding with it.

These wire feeders have motors that are about 8" long and 4" in diameter. All steel. The airco has both rollers driven. I could mount one of these things on my Jeep and use it as a winch

I hooked up the Lincoln power source (325 amp, 100% duty). I set it for single phase. Should be ok as long as amps is kept below 200. Everything worked, wire feed, gas solenoid, output voltage. I'll clean this up and it should sell at a good price. There are several on ebay from $800 to $1500. It is real dirty though, will need work to clean up. Some corrosion on bottom of case and on main panel.

The Airco wire feed has connectors for the Miller power supply. It feeds fine but needs a hub for the reel. Use a bolt and some washers and set up a 4" reel of 0.030 wire. I will probably try it with the Miller this weekend. The miller looks good. The hand crank for the voltage is real tight and must be 100 turns.

The Airco is a beast. Real dirty inside (all this stuff is covered in oil slime.) Took out the two bad capacitors. Typical, value/voltage is not printed on them (there are embossed areas where the values would go. Instead there is a Miller Electric part # the side.) Will see if I can get them. My searches show these are what fails on these units. In the back are water and gas solenoids, HF adjustment. So looks like TIG setup will be easy (will probably get a small air-cooled torch.) Front panel has HF start: Start, Off, Continuous.

I should take some pictures of the inside of the Airco. hundreds of pounds of iron, steel and copper. Lots of wires, relays, power resistors but no circuit boards. Must be early 70's at the latest.

Both Tweco #4 MIG torches look good and have 15' leads. The one on the Airco fed properly. Need new tips and shrouds are a bit ragged. They have quick disconnects. Switches work fine.

There are two arc stick electrodes. One is air cooled. Of the 3 units, only one ground clamp. I have a lifetime supply of 00-gauge wire.

We have welding!

Could not wait till weekend. Wired up the Miller to a 20A breaker (less chance of burning it up.) Again only single phase. Connected the Airco wire feed, gas etc. Flipped power switch on Miller. No sounds, nothing on meters, no lights (there are none)

Pulled trigger and loud slap of contactor, and voltmeter went to 20. Barely a hiss from gun.

Tried a short weld. Spotty results. Pulled torch from feeder and still hardly any gas coming out. Unscrewed nipple from gas solenoid and it was solid crap (looked like clay.)

Cleaned it out, pulled trigger and lots of gas. Did a few beads, still a bit spotty. Probably need to set the inductance higher (was probably set for high-current stick.) Also, tip is all corroded, will need new one.

These guns weigh like 5 lbs with the wire hanging down, real heavy duty.

Well, 2AM, time to get some zzzzs