Mig welder as a power source

Thread Starter

Ed.

Joined Nov 16, 2016
19
Hi, I have just joined this forum and am also a newbie when it come to electronics and this is my first post, so please bear with me.

I have a couple of projects in mind and I am thinking of using my large inverter MIG welder as a power source (24Kw), but potentially have an issue on start up. My MIG has very good control over the voltage output which ranges from 10-40V DC (it can regulate the voltage to 0.1 of a Volt) and up to 600 amps at 40V but the problem is that it also has a voltage no load spike of up to 75V when it first starts up the power (arc Strike) for a short time before it settles down to the chosen voltage .

The first project is a HHO generator to produce gas for a heating torch/furnace and the second is to make an electroplating tank. So my problem is that I would like to remove the spike when I switch on the power to the electrolysing cell and also to the electroplating tank. The electrolysing cell will be in three separate banks of 7 plates, each bank will be individually wired with a 20A circuit breaker, for different levels of gas output, but they can be switched on together for maximum output, and powered with 12-14V per bank which should keep the voltage down to about 2V per plate. From all the Youtube videos on these cells I have watched it seems that such a bank would draw about 15-20 amps per bank.

So with my very limited knowledge of electronics I was thinking of using an initial load such as a 500w lamp to absorb the initial spike and then add the connection to the electrolysing cell / plating tank which by that time, the MIG will have settled down to the chosen voltage. From what I remember, amperage is a function of the drain so that the MIG power source will output only the amps that the cell requires at the chosen voltage, is that correct?

Am I barking up the wrong tree or will this work, or is there a more suitable/elegant solution I could try to remove the spike? The reason I am think of using the MIG is that I already have it and also it will save me hundreds of dollars in yearly gas bottle rental charges, which for the majority of time will sit there idly until I need to heat something or electroplate some work that I have made.

What I also don't know is, is there any risk to the MIG welder? my logic says it shouldn't as a welder is designed to work as a partial short circuit power source but I could be wrong, I certainly don't want to damage the welder.

Any thoughts/ideas from anyone?
Voltage-Amperage Graph Miller invision 456P.jpg
Cheers
Ed.
 

Thread Starter

Ed.

Joined Nov 16, 2016
19
Miller Auto Invision 456P is the welder, the Auto circuit board for the robotic cell has been bypassed so it is just a basic MIG welder now.
 

tcmtech

Joined Nov 4, 2013
2,867
I see. :(

I worked as a welder service tech for a local welding supply business a number of years ago and got to know Millers inverter welder line very well. In the whole time I was there there was never a single day I did not have at least one if not 3 - 5 of them cross my workbench so I got to know them extremely well. Probably better than the engineers who designed them well. ;)

The spiking issue is easy to fix. Just cut the power cord off and throw the thing in a dumpster.
As a experienced service tech I can assure you I would never own any of Millers inverter welders even if someone gave me one (unless I modified the shyte of it to fix the numerous weak aspects of their design) and I am a true blue Miler guy. In fact my last name is Miller and all my go to day in and day out use welders I have are Millers. Just not any of those POS inverter units.

Other than that I would say put a high current switch or contactor on the output and turn that on once the units voltage stabilizes if the dumpster approach does not seem workable for you. :oops:
 

shortbus

Joined Sep 30, 2009
10,045
Maybe it would be easier and cheaper if a MIG is what your sure will work for you as a power supply to just get a cheap Harbor Freight one to use for this. Instead of screwing up a Miller. But an old Lincoln "tombstone" from Craigslist and a rectifier made from stud mount diodes would be even more robust.

I'm hoping you do a lot of research on this large of a HHO project. To know how to keep the hydrogen and oxygen completely separate. To keep from making a bomb, one spark could ruin your day.
 

tcmtech

Joined Nov 4, 2013
2,867
Maybe it would be easier and cheaper if a MIG is what your sure will work for you as a power supply to just get a cheap Harbor Freight one to use for this. Instead of screwing up a Miller. But an old Lincoln "tombstone" from Craigslist and a rectifier made from stud mount diodes would be even more robust.
The old lincoln tombstone units are constant current units with dismally low duty cycles in all but the lowest of ranges and quite far from being robustly built being very few but the very old units have anything more than light aluminum or copper clad aluminum for their windings.

MIG power supplies are constant voltage sources and more suitable for electroplating power supplies.
 

Thread Starter

Ed.

Joined Nov 16, 2016
19
Hi guy's, whilst I appreciate your dislike of the Miller inverters, I think that you have missed my point, whether or not they are any good is irrelevant and I am not going to get into a debate or defend their design or shortfalls, I have only owned one Miller welder so I do not know their overall general reliability but the one I own has been 100% reliable and hope that it continues to do so.

The point is, it is what it is and this is what I have to work with, so that is what I have. I do not wish to purchase another welder or a transformer, which then has to rectified etc. to do what this one already does.

If I have to spend hundreds of dollars getting another welder or transformer and added costs to do what is required, then I mights as well just gone and hired the gas bottles, although that still wouldn't give me access to an electroplating setup.

So as in my first post, I needed to find out if what I proposed will work with regard to the lamp idea or is there a simpler/better way to remove that spike, any constructive ideas are welcome.

I am also aware of the risks involved in having a combined oxygen/hydrogen gas mix.
 

#12

Joined Nov 30, 2010
18,224
This is where a schematic is important. If we could see the schematic, somebody might figure out what to change to get rid of the start-up pulse.
 

Thread Starter

Ed.

Joined Nov 16, 2016
19
Getting rid of the spike internally isn't an option as the welder still has to function as a MIG welder and that spike is essential to the proper initial arc strike of the MIG, sort of like a start up boost to aid the arc getting established. What ever I end up doing has to be as an external add on between the output cables and the electrolytic cell/ electroplating tank.
 

#12

Joined Nov 30, 2010
18,224
What ever I end up doing has to be as an external add on between the output cables and the electrolytic cell/ electroplating tank.
I don't believe you.
Switches have been invented. Any internal modification can be switched off so as to leave the MIG welder in its original condition.
Even if you refuse to add a switch, we can still benefit from the availability of a schematic.
 

tcmtech

Joined Nov 4, 2013
2,867
The Invision 456 series were designed to work as both a scratch start constant current TIG and stick power supply or as constant voltage source for MIG and spool gun work so they are capable of running 80 - 95 volt open circuit voltages so even if it's set for MIG mode constant voltage output it should not be spiking the output to 80+ v0lts for long enough to matter especially for electrolysis work.

To be fair I felt the Invision series were better built than the XMT series based on just not seeing near as many for the numbers the place I worked for sold that ever came back on warranty and I do have a pair of junk ones (smashed up pretty bad in a accident so I got them for scrap value.) in my shop that I picked up years ago intending to strip them of their parts but never got around to it.

I'm sure I could make one good one from the pair (with a lot of beating) but dang, it would mean going back on my word to never own and use a Miller inverter welder for its intended purpose. But then if I did build one for the pair I would have the opportunity to beef up all the areas I found were the most failure prone too. Still I have had them sitting on a storage shelf for close to 10 years now so obviously they are not drawing my attention too badly. Not even for parts salvage. :oops:
 

tcmtech

Joined Nov 4, 2013
2,867
I don't believe you.
Switches have been invented. Any internal modification can be switched off so as to leave the MIG welder in its original condition.
Even if you refuse to add a switch, we can still benefit from the availability of a schematic.
Take your pick!

Not much to work with detailed schematics wise.

https://www.millerwelds.com/support/manuals-and-parts

All major setting and functions are controlled off the logic board which Miller was pretty tight about sharing with anyone ever.
Even as a service tech all I got to work with for those types of boards was either replace it send it to them to be repaired to work with. :(
 

#12

Joined Nov 30, 2010
18,224
All major setting and functions are controlled off the logic board which Miller was pretty tight about sharing with anyone, ever.
Sounds like the wrong welder for this job.:( Another un-repairable like most retail products with a microprocessor in them?
even if it's set for MIG mode constant voltage output it should not be spiking the output to 80+ v0lts for long enough to matter, especially for electrolysis work.
That seems like a good thing.:)
I have had them sitting on a storage shelf for close to 10 years now so obviously they are not drawing my attention too badly. Not even for parts salvage.
Yeah...That's what I call a Bin Gonna (Bin Laden's cousin?). "I bin gonna do that for 10 years.":D
 

tcmtech

Joined Nov 4, 2013
2,867
Sounds like the wrong welder for this job.:( Another un-repairable like most retail products with a microprocessor in them?
Yea they have several uC chips on them. I never was able to get much of their control boards deciphered to figure out what they were doing but it's all related to several uC IC's in one way or another.
There were never any software updates though.
Just service bulletin notices that if a board went bad the newest version used in the most recent model was granted to be reverse compatible with all previous units and some models of machines had quite a few board revisions from their earliest production point to their last ones.

I know the XMT units had a bunch that and despite a old board and new one looking the same and connecting the same putting old board in a new machine would either and most often not work at al or if they did they caused all sort so off things to happen.

BTW, In service tech world the XMT stood for 'Extreme Maintenance Technology' as in, there was no simple maintenance to do when they broke down. Everything every time was s major and extreme bottom up machine rebuild. :mad:
They were amazing machines when they worked but every one I ever saw sold I outrightly told the guy buying it to trade it off for a new one before the warranty is out because if it quits after that, and it will, you will be money ahead to buy a new one rather than fix yours. My boss even backed me up on telling customers that.

Yeah...That's what I call a Bin Gonna (Bin Laden's cousin?). "I bin gonna do that for 10 years.":D
Yea every winter I think that I will pull one or two of those projects off the shelf and have ago at them but that never happens.
 

#12

Joined Nov 30, 2010
18,224
every winter I think that I will pull one or two of those projects off the shelf and have a go at them, but that never happens.:(
Every 2 or 3 years I get rid of most of my Bin Gonnas. I keep repeating this mantra: "The fact that I have not done anything about this in 3 years is a 'behavioral truth' which demonstrates that, deep down, I don't believe it's important." Then it goes in a Dumpster or the load headed for the scrap metal buyer.:)
 

Thread Starter

Ed.

Joined Nov 16, 2016
19
I case anyone is interested here is the correct pdf for my particular model via the serial number, the schematics are in the back part of it. The spike may not be an issue for the electroplating tank but I was thinking about adding a PWM controller to the electrolysis setup which has a max of 50V which might not go too well with that spike.
Similar to this:

http://www.ebay.com.au/itm/191780885010?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT

Don't know if I will need to yet and will decide after I build the cell and try it out on straight DC and see what happens. From what I have read the PWM module is supposed to enable a cell to produce more gas than direct DC. If the cell does produce enough gas then I won't worry about adding it as it will be just another thing that can go wrong.
 

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Thread Starter

Ed.

Joined Nov 16, 2016
19
I don't believe you.
Switches have been invented. Any internal modification can be switched off so as to leave the MIG welder in its original condition.
Even if you refuse to add a switch, we can still benefit from the availability of a schematic.
As for adding or connecting a switch to somewhere internally, I wouldn't even know where to begin or to find out where it should connect to. I did say in my first post that I was a newby to electronics. So schematics don't help me at all, and if I get someone else to do it, then I go back to my original problem of it costing more than the rental price of gas bottles so it defeats the entire exercise.

Hence the reason I wanted to go for a simple solution if it would do the job safely.
 
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tcmtech

Joined Nov 4, 2013
2,867
I can see your idea being practical for electroplating but for gas generation to run a heating torch or furnace system your end result efficiency is going to be so terribly low it won't be practical for anything. Especially so if you present torch work is running you hundreds of dollars worth of gas a year right now.

Even if you achieved 50% conversion 24 KW would only give you ~36,000 BTU (a big handheld propane torch easily does that) when in terms of a flame based fuel torch is not good for much plus your realistic operating costs for electricity plus all the system maintenance is going to be way higher than just using a common propane/air torch or common burner for heating anything.

What are you heating and how big and hot does it need to be? That in itself would be a far more realistic thing to discuss here.
 
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