I really can't understand ANYONE who would 'thumbs' down this video?? You take the Welding community clearly down a highly responsible, thorough and methodical context for how to approach this safely. People are weird. Keep up the great work Greg! I would've never thought of doing this on my own but now learning this old dinosaur from your instruction, I'm way more confident to consider it.

First and probably the best welders joke I’ve ever heard Greg. I was so excited to share that with some of my friends but they wouldn’t have a clue as to what I was talking about. Some things are best kept on ice for later. 👍

Holy Power Drain Batman! We'll take down the entire grid for Gotham City if we turn this bad boy on!! Lolol Old School is very, very, cool. Great vid and explanations of how these old mothers worked.

The amperage is controlled by saturating the magnetic field of the transform by controlling DC current going into the CWD winding through the rheostat R2. It is very simple and very reliable. I maintain a bunch of SRH333 & SRH444 welding machines which are very similar, just much larger.

I think I saw that one on marketplace. I’m excited to see the video.

You have yourself some very well deserved fans visiting this great channel. Nice work!

Give me a good old transformer/rectifier machine over these damn inverters! 41 years in the welding industry, I’ve learned that the inverters have limited lifespan’s, and when something fails on them, it costs as much to repair them as it did to buy it! Our shop bought several Miller inverters and they ran great for a couple years, then they quit. Sending them to repair revealed a PC board failure, the same one on each machine, and the repair cost was over 2/3rds of the purchase price! Meanwhile, the Miller SRH-333 transformer/rectifier machines that were purchased new in 1979 were still operating flawlessly in 2020 when I retired! And these things were used in heavy railcar repair, and had hundreds of hours of air-arc gouging on them! There’s an element of people out there that like buying new stuff all the time. I’m not one of them! Give me the bulletproof, tried and true, ugly as Fido’s ass, machine, and everyone else can buy the pretty little green inverters!

Thank you for the break down of this machine. The think that changes the voltage reminds me of a reostat

That is a really nice bit of kit.

FYI, I believe that JE serial number makes that machine a 1984 model.

The potentiometer is controlling the strength of the field on the top of the schematic. This is a saturable reactor and through physics (magic) I don't understand, controls the output of the main transformers. It's like adding a magnetic brake to the field. (Eddy currents)

Hay man you after my own heart with that old Miller welder I have a Lincoln 225 amp tombstone buzz box run on 50 amp breaker my old one the best I can tell is a 73 model the fan is down but going to get a new one can not beat old junk.lol

Rocking it old school!

Wow! Someone who actually knows what they are doin inside a old welding machine! Thank You! I am gonna subscribe!

Amperage adjustment is done by a 30vdc control circuit. It’s done with a Magnetic Amplifying Transformer. The more DC in the circuit, the less amperage you get out. If you lose the control circuit, check the little bridge rectifier. On my my Miller 330AB/P it was I believe a 40A rectifier. The second time it failed I replaced it with with a 70A on a heat sink. Never buy parts from Miller or Lincoln. You’ll pay $100 for a $10 part. Do your research and find it online from another source.

Not that we were discussing jank wiring or anything but I had a unit that had 2 regular 120 plugs that they must have been plugging into 2 different outlets/breakers from around the shop.

It looks like it adjusts the amps by using a 30v winding on the secondary run through a rectifier then through that variac(adjustable resistor) and then back into the transformer on a another secondary witch would induce a stationary magnetic field into the transformer this would then increase or decrease the inductince of the transformer and change how much current it can deliver(sorry for spelling errors)

Love the content bro! Keep it up...

I'm in UK and use an old Syncrowave 250 on 3 phase 415v 32amp. I didn't think these big beast would run single phase.

Ok so my high school class slipped a little over the years so according to the web it is approximately 75,000v per inch for electricity to jump a 1 inch air gap so Im assuming at 1/2 inch air gap 52:51 you need approximately 37,500v so your wrapping tape with your 120v per line in is completely is unnecessary as a matter of fact it may cause issues down the road .. if the tape heats up and starts to come off overtime .. this is why you never see tape been used in a location like that always clean terminals no tape that can get hot and catch fire. Don’t want to sound like an ass here but these machines were Engineered and approved by UL and CSA to work for years 😊 I believe the stud broke off when they disconnected the welder … that cable is way to stiff to be moving it around completely the wrong cable if you want to move it around should have had a lot more strands of copper like the one you installed nice and flexible.

😂😂 2 for 1 😂😂. Most of this is over my head, but you make it interesting and have a knack for dumbing down for the uninitiated. Another great video! Thanks!

Excellent video & nice score! I'm especially interested in part 2, to see how it welds & learn more about the bridge rectifier and choke (which I'm considering adding to a Lincoln tombstone).

RE studs .. don’t forget that it is only 120v going through each stud not 240v. However if you are running the welder at 480v or even 600v then the amperage will be much lower and the studs don’t give a crap about voltage more about amperage and heat .. lets not forget it takes over 10,000v for electricity to jump a 1 inch gap and your little stud could handle 10,000v as long as you amps are low .. if I remember my high school Electrical classes correctly

You are a smart man. I went to engineering school (mechanical)where I learned a little about circuits, but it wasn’t until I worked with cathodic protection and rectifiers that I became familiar with transformers, diodes, chokes, etc. You explain it well. The 7024 rods run well, btw. They lay down a lot of metal. Amps up, let it burn.

Nice! I'm about to be refitting my Dad's old Rainbow Warrier Welder from Sears in 1976. I'd imagine they are very similar. I know it has a massive transformer!

And the high low switch looks to be energizing 4 large coils or 4 small coils creating a larger or smaller magnetic field to feed the output could above and below the switched coils.

Random thought. I keep seeing these cool looking welder videos. They say they’re a laser welder.

If you find the AC only machines, don't be affraid to consider a heat sink and rectifier since they can be found online for well under $50. Maybe add a fan too and power supply if there isn't a fan voltage power source. The heat sinks might be something you can home brew from like a computer CPU. Like noting above, replacing the diodes, you can just purchase a full bridge rectifier either as super cheap lower current ones that can be paralleled together or just spend a little more for the larger current (Amps = A) single one well overrated for your machine. I didn't realized those Millers had such a large inductor to smooth the signal. Nice! Sure beats DIY homebrewed microwave oven transformer cores rewound as inductors to smooth the DC.

Very cool! I really like that old stuff, too. But not for daily work. When handling lower amperage a shoebox can offer, I would choose the shoebox. For higher amperage you would be in need of your personal power plant... I rebuilded my fathers transformer 220 or 400v 40-160A output, AC only. Very smooth arc and fun to weld with but... heavy and inefficient. (not as heavy as your new old miller😂). To be honest it was basically for a tribute to the "old days" as well to my father himself who welded with this machine for almost a lifetime. So I will keep and use it - for fun, for understanding old technique and for the history within. I think that small brass stud is sufficient because of the very short distance it has to carry the power compared to the cord. Your "jumpers" may help to anneal the poor conductivity of the steel studs. It is interesting, how things are made somewhere else, because here we are tought never to solder on crimpc-onnectors or bolted terminals because the solder behaves like a highly viscose liquid under constant pressure and float so that the connection becomes unstable over times. As always: great video on a very interesting topic! I really appreciate that you get into savety in first place. An other viewer moaned that every idiot could rebuild such a machine. I partially agree but that idiot may somewhen in his life(perhaps near the end) start to smell like grilled chicken. So everybody who does not want to end up sa a "welldone" hillbilly should take advantage in watching this video and follow your advice.

Meanwhile, that Machine cranks up and the neighborhoods lights all dim 😂

That machine with dinse connectors would just make it sweet.

It's a rheostat yes it varies the voltage going through the transformer it's an auto transformer

Reostat to control amps out.

Could you plug it into a landline to be safer?

I have the Dialarc 250 HF as my Tig machine. I have the Titanium 225 for SMAW. The Miller is on a 240V 100 amp service. The T225 is on a 240V 50 amp service.

Yes sir I'm a fan of the old school welding machine those are the only ones that are school had that's how I was taught to weld and you can add a suitcase to it too. I'm finding a lot of older Miller machines I've been entertained for a dynasty 500 DX that is down the road from my house. The old welding guy has been trying to get rid of it but nobody is interested in it. He has given me a hell of a price for it to.

Nice thanks !!! Are you at all familar with cebora welders?

Meh. I’m reading the guys here who love these old machines. They’re ok. Nit great. Sure they last, but really, that’s not a big deal. A company writes off their equipment. No big deal. There are very good reasons these things have died out, and good riddance. It’s odd how they do these connectors. Copper is around 90-93% efficient. Brass is around 30-40% efficient. The steel is around 25% efficient. I would never had designed something that way. It gives me the chills looking at it. It’s really called three wire cable. But all three are conductors so I suppose it’s technically correct. Greg, I wouldn’t solder that as soldering creates a higher resistance joint. Normally it’s not too much of a problem, but with really high amperage connectors it could cause heating.

Another interesting item is that Miller supposedly no longer produces any transformer type machines. Even their longtime buzz box “Thunderbolt” machine is an inverter. An inverter that’s easily stolen because it will fit in a lunchbox!

an old miller man i am a. sucker for old stuff to

Miller uses codes based on the serial number to give you the manufacturing date.

i run nothing but 60 year old welders and i never have any issues with them

The word you're looking for is rheostat, power is controlled by magnetic amplification.

Now draw for us Why 240v is more efficient then 120v... And the Diff between 1 & 3 Phase... And the Diff between Pulse setting's on newer stuff...

A thyristor?

Ok looked again closely at your video looks like you used shrink wrap not tape 👍🏻 my bad

i bet they use capasetrs now also DAM DAM DAMN auto correct

Big ha ha ha... The whole space... Mwahahaha. As little as she is she sure is cute! And for 250 280 a value as well!!! Mine is at least twice as big. And weighs probably about 1500. Regardless, she's a beaut! Good buy! (I'm assuming I'm that guy...)

I really enjoy the channel and I’m definitely not trying to sound like the typical internet hater but…. Why buy this at all? Wouldn’t something like that Titanium 225 do everything this machine will do? Aside from duty cycle of course, it seems like $300 could be spent on something like the titanium with the advantage of a warranty with none of the disadvantages like lack of portability and huge footprint.

And then build us a Stick Welder out of a Microwave Transformer like those dudes from India Do... haa

Seriously. You created a video on how to rewire a welder. Any idiot can do this.