I think I need a new welder

mkirsch

Well-known Member
Starting to think there's something wrong with my old Lincoln 225AC tombstone with Miller 150DC rectifier... I think it's getting tired after 40 years of abuse.

I can't run 1/8" rods for %$#@ anymore. Hobart 6011 or 7018, all they want to do is stick and sputter even up to the rectifier's max of 145A. Makes me look like a total hack.

It used to work much better. I have no problems with Dad's Hobart Stickmate so it ain't me...

I thought the old Lincolns were bulletproof?

Any thoughts on a replacement? I'm real curious about those multiprocess welders like the Miller Multimatic 200.
 
take the diode out of line and try to run that 1/8 6011 on about 95a straight ac.. etc. see what ya get.

are you running 6011 dc or 6010?

in any case.. if it runs 6011 ac, on 95a the machine is probably working, and i'd look at the diode pack..
 
For giggles can you bypass the add-on rectifier and try the AC side only with the 6011?

If it still acts funny then my bet is that the selector switch is corroded up. There are How-to instructions on the web on how to clean this switch. Most parts are still available from Lincoln if you were to need any, but you usually do not need any. Usually some fine sand paper and scotch brite pad is all you need after some switch disassembly. Would we worth your time to try it.

For a replacement welder (which is very unlikely) then I would go either either Hobart Stickmate or Miller Thunderbolt (they are same welder actually). There is even a bigger version that is available over the standard 230AC/160DC output model if you willing to spend extra $.
 
If you think you need a new welder I would go with that thought! WooHoo! An excuse-ummm,,errr-reason to buy a new welding machine.(Doesn't mean you cannot keep and fix the old one too, right?)
I bought an Everlast Stick, TIG, plasma machine and think it is awesome to have the extra process abilities as well as the small package it comes in!
Great machine for the money. Hard to go wrong with a Miller though if you can justify the $$$...Sure love my Miller 211 wire feed. It just seemed worth the extra bucks for a name brand wire machine that I use a lot.
 
I've added a rectifier to my ancient Smith stick welder. Can you tell me the value of the capacitors on your machine.
 
I'd be more inclined to bet on the rectifier pack or simply bad cables. Those go bad too... more than you think. Doubt it's the old Linc. Those things are pretty well indestructible.

Rod
 
Also check if your open circuit voltage at the AC side is about
80V.
If good voltage level, it can be connection problems, wiring, or
diode(s). If diodes, one may be open or high resistance.

If low voltage level on all switch settings and source breakers
are good, with no load (open circuit), then the transformer may
have shorted windings if the magnet wire insulation got too
hot. But that older unit probably has pure copper windings,
very good stuff! So if it is low then something is wrong back
towards the transformer.

Greg
 
Adding capacitors will bring the open circuit voltage up to 95 volts.Too much.You need a choke coil on a DC converter.
 
How does it weld on AC?A 225 Lincoln should have an idle current of 2 amps.Have you measured the primary voltage.Should be 240.
 
Oh my...
Sorry I was over optimistic.
I've never owned one until recently and a lot of folks keep saying the old units had copper and not copper-alloy. Some say that they are now all Aluminum which would really be high resistance.

So were the older units still only good for about 20% duty cycle at 225 Amps?

Greg
 
I have a circuit diagram from a manufactured unit that indicates capacitors, but does not give the capacity. I think they are used to smooth the peaks.
 
It's funny how people rant about the AC 225 being so bullet proof yet you never see any in welding shops. They're OK for a hobby or small farm welder but are still a low end machine. They were always 20% duty cycle.
 
I am a beginner stick welder with an AC-225, 275A diode bridge, and a choke coil out of a Weldanpower G8000.
My only fear with my 20% duty cycle limit is overheating the transformer's winding insulation.
My only hope is to attach a thermocouple to the transformer laminations so I can monitor the core temperature every so often between welding runs.
And stop when the temperature rises by about 40 deg C.

Greg
 
OK let me take a stab at this...
Yes the cap smooths the full-wave bridge-rectified DC and also raises the average voltage to the level of the top of the peaks.
Bad news is when you go to start the arc you get a big nasty snap :-( , not good...
Having just an inductor choke coil is good for starting the arc and for maintaining the arc.
The coil limits the inrush pulsating DC current when starting the arc.
The coil also maintains the pulsating DC arc nicely once started.

All I can say is if you insist on a big fat cap, then better have a "large" choke coil to limit the inrush current when starting the arc.



Greg
 
Just use it. I doubt you're going to pouring rod after rod of 5/32" or bigger rods. Do a weld, chip it off and do another weld. That will give a little time to cool off between rods.
 
Yea I used 5/32 rod after rod just last week and did stop to let it cool at times but I tell you what I could almost fry an egg on that €£^*€ transformer. Reached underneath for grins just too see how hot and man I was worried.

Don't have the the dough for a nice power plant 100% duty rig so I'll be careful with what I've got for now.

Regards,

Greg
 
Its time to buy a Lincoln Idealarc 250.Weighs twice as much as your 225.Needs a 70 amp service.A new one costs 2 grand.Duty cycle is much better.
 
Hi 36 coupe,

AC or AC/DC?

In 1964 I had what was considered a decent job for a high school student---box boy in a supermarket making around $2 an hour. Today, the minimum wage in this state is more than 4 times that, but a Lincoln 225 AC is only about 3 times what you paid that year. So things are getting cheaper. Of course, gas now costs about 15 times as much as it did then, and houses cost about 25 times as much, so you've got to pick your bargains.

Stan
 
Greg,

Why do you say that aluminum windings would have really high resistance? Aluminum has the 4th least resistance of any metal (silver, copper, gold, aluminum, in that order). It was used for house wiring in the mid to late 20th century (that use was ended for problems other than its efficiency), and it is currently much more common than copper for feeder lines in residential and light commercial installations (larger installations than that I don't know).

The Lincoln Electric representative/historian who told me that Lincoln 225 buzz boxes have never been manufactured with copper windings on the transformer, said that some Idealarcs were copper and some were aluminum but that I would never be able to notice the difference. My guess is that it's a status kind of thing, as it is with most consumer products: If someone knows there's a difference, then they swear that they can detect the difference, but blind comparisons usually demonstrate that they can't. Well conducted tests have shown that people who won't drink any other vodka but Grey Goose (or any other high priced brand) are consistently unable to pick it out of a group of six brands---including really cheap ones---in blind taste testing.

Stan
 
I was misinformed about the AC225 having copper windings as well... They have been aluminum from day one...
 
Frown :-(

So what's going on?
Able to run with AC, fried diodes, connections, cables, smoked transformer, we're dying to know....

Thanks,

Greg
 
The difference between pure copper and pure aluminum is significant when you are talking 225 Amps of current, enough to generate excessive heat.

Pure copper has about 38% less resistance than the same size aluminum.

My guess is that they are using an alloy mix that has resistance closer to copper.
The only reason to use higher resistance wire than pure copper ( other than cost) is to form a current limiting action at the cost of excessive heat.

Aluminum house wiring in the old days was downright dangerous especially with high current stuff.

BTW, I have a piece of flaked off wire insulation from my AC-225 and will check at what temperature it starts to melt. Let me just say this, i held a lighter to one of those flaked off pieces and guess what. It not only melted but caught fire too. Those engineers are not formulating the wiring varnish very well!

Regards,

Greg
 
Well, two things (and then I'm not going to post on this thread any more---I feel like I've about run what I have to say into the ground). Pure copper may have 38% less resistance than the same size aluminum conductor, but aluminum has a moderate weight advantage and a significant cost advantage over copper so there's no reason to use the same size. Aluminum cables supplying electricity to a residence are much larger than copper cables which would carry the same load, and they're still just a fraction of the cost of copper.

The other thing is that aluminum house wiring wasn't dangerous because of heat generated by high resistance. It was dangerous because it expanded and contracted at a different rate than the dissimilar metal (i.e. non-aluminum) screws to which it was attached in outlets (and probably switches, too). This caused attachments to loosen which led to arcing which led to fires. This is still a problem in electrical service panels where the aluminum supply cables attach to the lugs. It's less serious than the old aluminum house wiring because most homeowners and amateur electricians are rightfully wary of working this far upstream, and real electricians know how to deal with it. But lots and lots of illegal and/or incompetent wiring of lighting and outlet circuits has always been done, and always will be. That's why aluminum house wiring stopped being legal many years ago.

I don't think you and I are disagreeing about anything. We're talking about different aspects of the same thing.

Stan
 
Copper is better but for most projects you'd never notice any difference. The best example of why copper is better deals with Lincoln SA 200 engine drives. Pipeliners noticed that on the machines made from about 73 with aluminum shunt coils, that the machines would heat up and not keep consistent amperage settings. They'd start off in the morning and after a couple hours have to turn their heat up. Then after they had lunch, the machines would be too hot and they'd have to turn them down again. For THIS application, the aluminum was a real PIA! So much so that Lincoln went back to all copper in the Classic and later pipeliner series machines. Price out a 200D pipeliner and you'll see they cost more than a larger non true DC generator machine.
 
It was just AC, delivered to my door.I bought a 50 lb box of 1/8 rod for 9 bucks.In any case a 93.00 selling price was too low to use copper windings.There was a 180 amp welder made by Lincoln that drew just 37.5 amps at full output.It must have had power factor capacitors to keep input current that low.I have done minor repair work on small welders and never saw any copper wire in the main windings.
 
You need a bleeder resistor across the capacitor bank to discharge it when the welder is turned off.Finding a choke coil is a major problem.I made one for my converter.Replacement welder parts must be made with gold.
 
There a Lincoln Ideal arc on craigs list for 160 bucks asking price. AC/DC. If I were younger Id buy it.My DC converter cost 100 bucks to build.I had a lot of the parts on hand.You can put a small welder into failure mode if you push it.
 
(quoted from post at 12:55:22 07/05/13) Frown :-(

So what's going on?
Able to run with AC, fried diodes, connections, cables, smoked transformer, we're dying to know....

Don't know what's wrong with it yet.

Tried on AC and ran a few 1/8" 6011's at 90A. Runs better, but I'm still having a problem striking an arc.
 
mkirsch,

Glad to hear back.

May want an electrician if not yourself to help you out. I'm sure
you know 240V is not something to take lightly! No pun
intended.

Since you are using AC and having trouble striking an arc,
now check the AC open circuit voltage where the cables
hookup. Should be about 75 to 80 volts AC though the entire
switch positions. If good voltage level then bad connections or
high resistance somewhere when trying to strike an arc.

If low then could be a worn out transformer, provided you have
a good stiff 240V source.

Check for 240V on the primary even when striking an arc.
Leave the AC voltmeter hooked up to the source and stick the
rod to see if your source is stiff!

If that's good and good connections, good front panel power
switch, cleaned secondary switch contacts for setting the
current, and good as new cables and lugs, then you may have
melted wire insulation in the transformer itself.

Like others say, the source should have 2A of idle current with
open circuit electrode. The idle current may be higher if the
primary has shorted windings. May not see a difference if the
secondary has shorted windings but will see a lower open
circuit voltage on the secondary.

HTH,

Greg
 
Thanks 36 coupe,

I was lucky to get some parts cheap locally.

$50 for Weldanpower inductor choke (never used)
$60 for four 275A stud diodes
Free aluminum heat sink plates for diodes
Etc. etc

Well I have to hold on to the money right now, times are getting tuff for somes of us...

For now I'll just keep the run time down and watch the temp.
I have a K type thermocouple 3" stainless probe that I'll thermally attach to the laminations and run the lead outside to read temps. I'll have to turn the welder off before connecting the probe since the mag field will cause erroneous measurements if not overload the meter input.

Take care,

Greg
 
The primary voltage has to be measured, it may be low at certain times of day in some places.My 225 has a tap for low voltage.I am at the end of a three phase line in a rural area.Voltage is steady at 242.I would measure primary and secondary voltage when the welder is burning a rod at 150 amps.
 
When you say "melted" that reminds me that the original cooling fan on this welder seized up, and Dad continued to use it that way for quite a while. Never anything major just farm repairs.

That's how he ended up with a Hobart Stickmate LX for Christmas one year... and how I ended up with the Lincoln.

I replaced the cooling fan with a big 220V computer muffin fan, but I don't know if it's moving enough air. Even that may be a moot point if the damage was already done.

I'll check it out using your recommendations when I get time.
 

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