Eco mod my welder
 

I picked up a craftsman 230 amp AC welder for $100. It was in rough shape.
One thing I do not like about its rated for a .77 power factor.

This means that it draws around 11,000 Volt Amps of reactive or apparent power for this highly reactive inductive load. That is 50 amps of 220.
It draws 8.6kw of true power.

If the power factor was corrected to closer to 1 it would only draw 39 amps.

I figure if a few high voltage non polarized capacitors can knock 11 amps (of 220!) off the reactive load. How can I not do this?

Aside from saving 11 amps of utility power I would like to be able to run this off grid on a generator and I don't want to screw up the power for any other items being run off the generator. Also saving 11 amps of 220 when you are on a generator is very valuable.

Only problem is I am having trouble with the math that you use to figure out how much capacitor you need to correct power factor.

I think it will take 3 or four 100uf motor run capacitors to fully correct the P.F. when running the welder at full power. Or more I really don't know for sure.

Only thing I can think of is run it through my kill-a-watt meter, up to 20 amps and check the P.F. with and with out capacitors and then wing it with an amp clamp only from there on. If I get the power factor corrected it should read closer to 40 amps, if not then closer to 50 amps.

Then once I get this power factor thing straightened out I am going to convert it to DC.

The difference between an 0.8 power factor and a power factor of 1 means the engine has to work up to 27% harder to drive the generator.
On a generator you may not have the horsepower to do that.

oilpan,

The main problem with passive (capacitor) PFC is that the capacitors will continue to draw current when you are not actually welding. Sure, you might use 10 amps less peak current, but you will be continuously drawing more than that 10 amps at idle. Instead of inductive reactance at full load, you will be drawing capacitive reactance at part load and idle.

The other problem is that power factor is a moving target. Depending on how many amps and how much inductance (dig or sharpness control) you are using, the power factor will change. The phase angle will change due to amp draw, arc length, material thickness, grounding method, cable length, etc. ON ITS OWN.

Another thing to consider is that capacitor "padding" the input of the welder only corrects for linear (or passive sinusoidal) mismatching. Anything active in nature (generators, regulators, rectifiers, transistors, etc.) pushed or pulled through causes harmonics, which could interfere with other parts of the system. One bad situation is feedback with the generator due to resonance.

Not trying to put you off your idea, but this is the kind of stuff that electrical engineers have fun with. Of course, they use sophisticated, expensive equipment, and even more sophisticated formulas and methods of figuring out what's actually happening in the circuit. Cuz with AC power, most standard test equipment lies to a certain extent.

It looks like I will be trying to find a happy medium then.
I think to cancel out that apparent power with the welder going at full power would take 480uf but all that unused reactance would be a waste. I don't plan on running full power very often.
I ran my machine some today and I think I will be keeping it between 120 and 180 amps for now 145amps seems like the happy place.

I could always run the capacitors on switches to cut way down on unused reactance.

I got the 100uf motor run capacitor I ordered in and promptly ran a quick test. I plugged it into my kill a watt meter.
The kill a watt meter detected 0 amps, 0 watts going to the capacitor, which is exactly what I was expecting.

What you are saying about reducing the load on a generator may be correct ?

But , I would like to point out to you , the reactive amperage is not read by the traditinal power company mechanical watt meter . Which is one reason PF is kind of a touchy subject with the power company . Not so much for residental , but for commercial or industrial companies .

I do not know if electronic watt meters can read reactive amps ?

I worked at an iron foundry , years ago . Two electrical induction furnaces . ( Big inductive reactance ! )

They each had a capacitor bank . The controls would switch in / switch out more or less capacitors . It would maintain a PF of from .95 to 1.05 .

Lastly , as long as you are hooked up to commercial power , it is probably a non issue , as long as you are not doing much welding . If you are doing a lot of welding , maybe so ?

God bless
Wyr

I don't know what you plan to do with this welder but a 1/8" 7018, or 5/32 6011 rod will probably run comfortably at 110 amps or less. Your arc voltage will probably vary between 20 and 30 volts. 30 x 110 = 3300 watts when welding. You will You guys will have to do the math to account for losses while you backtrack to the 240v line. Your biggest amp draw will be when your rod sticks to the work. :)

Well it turns out the power meter can read apparent power.
Since I belive in math and reproduceable scientific experiments (unlike the AGW community), I will tell you what I did and how I did it. I dont make crap up and tell you to believe it.
You will need a power company power meter, kill-a-watt meter, 200w incandescent light bulb with drop light, and a 110v arc welder with a really horrible power factor.
I have a 2 main panels, since I split the lines coming out of the power meter. I turned off the house power so the meter was stopped. This leaves only my small power panel energized. No chance something can kick on and screw with my test.
Test 1, plug in the incandescent and count the number of seconds between marks passing on the disk.
It took 3 seconds for each mark to pass and check its actual consumption on the kill-a-watt meter.
Test 2 used my small arc welder with its horrible 0.22 power factor. It draws 120 watts of real power and 500 some units of apparent power. I removed the drop light and plugged in my welding machine in to the same kill-a-watt meter.
When the welder was flipped on it turned the power meter disk much faster. It was between 1 and 2 seconds per meter count.

Now if power meters only read true power then the welding machine with its 120watts of true power should have turned the power meter much slower than the 200w bulb with its 207 watts of measured true power.
Wouldn't you think?

To adress "power factor is always a moving target in a welding machine", umm its not.
Basically the excessive reactive power is a fixed amount. Then when you strike an arc true power and apperant power increase in unison, raising the power factor from say 0.22 or 0.33 to 0.6 or 0.7 at full load while welding depending on the machine. There is still roughly 400 more volt amps than watts, at no load versus full load but the ratio of watts versus volt amps is a lot better when under load.
The machines draws the same power factor reguardless of the output amps setting at no load.

I power factor corrected my mig welding machine with great results. I figured I needed at least 30uf of capacitance to get my machine into greater than 0.9 power factor territory.
So in installed a terminal board and put 30uf of 200v metalized film capactors in parallel with the welding transformer. At no load it brings my mig welders power factor from 0.33 to 0.55, while welding it increased the power factor from 0.7 to 0.92. I have some 2.2uf 200v metalized film caps in the mail, I am going to fine tune the pf up to .96 at full power.
And best of all its putting out 10 to 15 more amps than ever before, its drawing more true power and apparent power compared to before with the same settings as before and putting out more welding amps. Thats so not not a problem for a little 110v mig, I just turn down power or move faster.

Looking at a newstyle digital power meter there appears to be 2 power consumption measurements.
One reading appears to be tracking high power factor consumption when VAs are 20% higher than watts and the other reading appears to be billing just regular wattage.

I am sure power consumption at less than 0.80pf comes with a nice penalty. I would like to live in the same town where everyone has this meter.

So the mig welding machine is running well above 0.80pf, up to .95, but I have 2 problem air compressors, one runs a .7pf after some minor power factor correction (I added a salvaged 8uf oil filled motor run capcitor) and i have another compressor that runs a .44pf.

Adding 200uf of motor run capacitors to my main compressor has reduced apparent power consumption by 400 VoltAmps.
The pay off for this mod is 200 hours of run time, if there is no low power factor penalty on the digital utility meter.

Good to see your success with this , sounds like you have it tweaked perfectly.

The current electronic residential meters do read power factor. According to the elec guy that I talk to that installs and sets up the commercial meters the elec company does monitor what is going on the PF in residential applications and said not to be surprised if it becomes a place for fees like it is for commercial as it has been talked about.

I have seen a digital residential meter that had a tally for counting "80% VA" power consumption.
I can only assume they are collecting your power consumption when average power factor going onto the house drops below 0.80, to charge you more.
The meter I saw had collected 100s or thousands of regular watts of consumption, but only 10k of the infamous "80% VA".

On an electromechanical residential meter, it doesnt track power factor but as you use more VoltAmps those VoltAmps spin the meter faster.

I was told , in school , that the traditional electro-mechanical meters Measure only true kilowats , not volt amprts ?

God bless
Wyr

Check out my watt versus VoltAmp tests in the OP using a residential electromechanical meter.
It definitely responded to the excessive VoltAmps load I put on it as if they were watts.
The way excessive voltamps load down a generator I think the power company should charge for them.

I originally started out on this power factor thing to make my machines corporate with long extension cords and being powered remotely by a generator. Its turned into an attempt to turn the utility meter slower, which is working quite well.

I recently constructed another air compressor. A 220volt machine this time.
I was able to power factor correct it to save about 1.7 amps, about a 5% power savings, nothing compaired to the 25% to 30% power savings capacitors were giving me on my 120v machine.

I am having another go at power factor correcting my large arc welding machine.
Since I do not have a machine that figures power factor cosine for 240v power I am shooting from the hip with my box of capacitors and fluke325 amp clamp.
First I like to start small. Power factor correcting the blower fan that cools the transformer.
It started out using 0.71 amps of 240v power, which seems like a lot.
Started off by connecting a 8uf capactor to the fan, that reduced power to 0.55 amps, not bad.
Then tried a 10uf which I figured would be to big. Power consumption went up to 0.65 amps, definitely too big. Next try was with a 4uf, power consumption was down to a half amp even.
Figured what the hech might as well try the 5uf cap I have, that reduced amps to 0.48, not bad, thats saving 55 VoltAmps from just the fan alone. Thats enough power to run a fan or some lights.
I run the fan a lot, I cut power to the transformer and just run the fan to cool down the trasnformer in between welds.

Now on to the main arc welding transformer....

Other power factor corrected 240 volt transformer welding machines run 40 to 60uf of capacitors connected line to line. So the amout of capacitance will be some where around there.

The main transformer runs 3.77 amps no load.
First try was with the 10uf capacitor since I already had it sitting there, result: it dropped the power consumption to 3 amps even.
Next try was with a 25uf capacitor, that dropped no load current to 2 amps even and quieted the angry hum the transformer makes.
Still thinking there is more to be had I connected the 10uf capacitor to the 25uf, making a 35uf capacitor, that reduced power to 1.71 amps.
Then swapped out the 35uf assembly for a single 40uf capacitor, that increased power consumption to 1.76 amps.

So 35uf of capacitance saves around 535 voltamps at no load.

For testing I am going to connect twin 440volt 40uf caps line to neutral, since arc welders have a way of killing 440volt motor run capactors connected line to line.

Weld output appears unchanged.

Connecting the capacitors in parallel, running each capacitor L to N seems to lessen their capacitance, causing the machine to draw 2.2 amps at no load as opposed to 1.76 amps during the quick and dirty L to L single capacitor test.

Twin 55uf capacitors connected L to N seemed to do the trick.
Twin L to N 55uf capacitors plus a 5uf for the fan is almost exactly what welding machines running PFC use.

It would seem that when you run them at lower voltage they have less capacitance. Or has the effect of serriesing them up.

I ordered a set of 80uf motor run capacitors to install L to N on each line. The L to N connected 55s are causing the machine to draw around 2 amps. The 80s should get that down to around 1.75 amps.

I salvaged some actual powerfactor correction capacitors made by mallory.
They are 60uf, 480v rated and are about 3 times the size of a standard 440v 60uf motor run capacitor.
Not sure what to do with them. Had I found these before I bought the 80uf capacitors to put in my large arc welder I would just use twin 60s, since its hard to beat the pirce I paid for them, free.

I did some more work with my mig welding machine. I swapped out the internal component capacitors for a single externally mounted 40uf motor run capacitor. I found the 40uf reduced amp consumption a little better than 30uf. Total saved is about 2 amps. It wont save much on the power bill but it will make the welder more extension cord or generator friendly.

I was looking at the PF of my well pump and its 98 after start up but it's around 50 or so when it starts. Big dip at start up with it course it's on a 100' cord though it's only 3' from the panel. I haven't built a permanant enclosure for it so I haven't run permanent power to it yet.

Hey .98 is good for any motor. I cant get most of mine much above .90pf.

I power factor corrected my small 110v powered 100amp out put craftsman arc welder.
At no load it goes from .30pf to .75pf with the addition of a 50uf capacitor. Under load I expect the pf to go up to some where around .90pf.
I used 40, 50, 55, 60 and 80uf capacitors to test it out.
The capacitor is just sitting on top of the machine, I have not installed it. Hopefully I can make it fit in there with all the DC output stuff and ducted fan I added. I rather not attach it to the out side since I want to keep this machine portable and self contained.

On my full sized 240v powered arc welder I tested out those very large mallory power factor correction capacitors I salvaged. They worked better than the two 80uf motor run capacitors.
I will sling the mallory capacitors up under my large machine. Since for some reason two 60uf capacitors wired L to N gives the same performance as a single 40uf capacitor wired L to L.
I have been getting very good performance out of two 55uf capacitors wired L to N.

Next PF correction project will be to do a mild pfc on my trouble some oilless air compressor that runs a .44pf at full load. It will pop a 15amp breaker on all but the coolest days.
I am selling it to my friend who says he would really appreciate it if I could make it not consistently pop a 15amp circuit breaker, he has barrowed it before. I guess he has or has used it on a breaker box full of 15s.
Challenge accepted.
Bet I can trim at least 3 or 4 amps of draw.

In other news...
I installed the 50uf 440v motor run capacitor with MOV protection inside my small arc welder. It barely fit.
Next test will be to see if it corporates with my small generator any better. The capacitor will save about 2 amps, which could be huge to this small generator.
Now this little welding machine weighs about 50 pounds with all the stuff I added. Bridge rectifiers, heat sinks, 2 good sized inductors, PFC cap.

My refrigerators power factor is 0.98

I believe they charge industry extra $ for the low power factor of equipment/electric motors and whatnot.
I'm not sure if is still true today with the high tech meters but it was.

Is there any worry about the life of these capacitors?

Yes there is major concern for the life of the capacitors in non motor applications.
These capacitors are all rated for 370 to 440 volts and it turns out motor run capacitors work really well on motor applications L to N and L to L.
They dont work so well connected line to line (only 240 volts) on stick welders. Seems that motor run capacitors burn out after a few seconds of arc welding when connected line to line with out MOV protection.

I have used motor run capacitors in my stick welder wired line to neutral with out MOVs and have burned 20 pounds of electrode with out any problems.
I have since upgraded the stick welder to actual pfc capacitors rated for 480v, wired them L to N and then gave them MOV protection. Dont think I will have any more problems.

I partially power factor corrected my .44pf oilless air compressor for my friend. Its a compact little rig, there is only room for one capacitor. Knowing how bad the power factor is I know it will need way over 100uf to give it an ideal power factor correction.
I warmed up the compressor for a couple minutes and did a baseline, compressor shut off at 16 amps.
I added an 80uf capacitor to the circuit (just to help quantify added capacitance to amp reduction), that dropped amps to 13.8 at shut off.
Then removed the 80uf cap and put a 100uf capacitor into the circuit. That dropped the amps at shut off to 13.30amps.
That brought the pf from .44 up to .60pf and should keep this machine from tripping a 15 amp breaker when used on hot days for extended runs or when on an extension cord.
Good enough I guess...

Now some one made me an offer for my 3 power factor capacitors, so I will pull the 2 I put in my welder and go back to motor run capacitors.

I installed a 0 to 300volt gauge with the MOVs hooked up inside the gauges handy box. MOVs are connected L to N since radio shack stocks big cheap120vac MOVs.
The gauge and MOVs are hot when ever the machine has power.
I installed a volt meter because my machine runs perfectly at home, because at home its got a sub panel at the service drop, but when I take it mobile some times it acts strange like its losing a lot of power. I will be connected to a 50 amp circuit but who knows that "50 amp circuit" could be 60ft long and made of 8ga wire or I could be on 2 legs of a 3 phase connection only getting 208v.
If I am on 208 I will know right away, if on a circuit made of a long run of under sized wire I will set the machine to 100 amps, connect 2 work leads and short curcuit it through the work and see how much input volts drop.

I built another one. I found a kind of old 1.5hp "speedy air" made by Dayton, in Ohio. I wanted to make this a mobile 220 volt compressor. (my other garage bound air compressors never see the light of day and don't have wheels) I got this one from the scrap yard. The pressure switch had corroded and was open so the genius that owned it last hot wired it so the compressor switch runs when ever the machine is plugged in. There was no way the machine would ever build up to any where near shut off pressure on any 120v circuit that was any where near being up to code.
The machine was hot wired for 120v and drew 20 amps (at about 1000watts, a horrible P.F.) just turning the compressor with the tank wide open. I am thinking the people trashed it because the pressure switch was bad (A $20 fix) and I know it flipped the breaker as soon as it started to build pressure since it was drawing almost 21 amps at no load at full load, based off what it used for 220 it would draw nearly 40 amps at shut off had it been left wired up for 120v power. That's bad because the max rated amps on the side of the motor says 22 amps for 120v power (and 11 amps when wired for 220).
So I switched a few wires around according to the diagram on the side of the motor, converting it to 220v and installed my favorite 220 volt power connector the NEMA 10-30 clothes dryer power cord.

So now converted over to 220 at no load it was running about 9 amps. With no capacitor running a wildly lagging power factor it was hitting 18 amps at shutoff pressure. A little high.
I knew it would need around 100uf so I installed a temco 440v 100uf motor run capacitor in parallel to the motor assembly. That dropped the amps down to right about 10 amps even at shut off.
Figuring less may be more I switched over to a Dayton 80uf 370v motor run capacitor. That only increased amps to 10.20 to 10.30 at shut off. That tells me 100uf was on the verge of being too much capacitor.
Then to test what a much smaller capacitor would do I put a 440v temco 40uf on there, and amps went up to 13 at shut off.

I did this 220v power factor correction shooting from the hip, just using my fluke324 amp clamp meter. I have a 220v single phase energy meter that will display P.F. but I have not bothered to rig it up yet.

This machine I want it to have a slightly lagging P.F. since it is a mobile unit and will be powered by a generator at some point. This one has wheels and a handle.

But I know some of you are thinking "10amps of 220 is way more than 1.5hp".
Yeah the motor gets a little warmish but it will survive.

The primaries and secondary's are insulated from each other. I already tested that.

I needed a tig welder so instead of spending $1500 on a decent miller or rolling the dice on made in china garbage I added a tig torch to my AC only craftsman welder I original bought for $100. I converted it to DC for around $50 then picked up a tig torch plus consumables for about $250.
http://ecorenovator.org/forum/attach...r-img_0626-jpg
http://ecorenovator.org/forum/attach...r-img_0687-jpg

My newest welder ecomod is to power my mig welder off a 2000 watt samlex pure sine wave power inverter and my 60 amp hour LiFePO4 battery.
I tested it on my 40 amp hour battery, then expanded it to 60 amp hours, a mod I have been sitting on for too long.

My 40ah AMP20 cell battery had just enough power to run the power inverter with the welder on it at full power for a shot time. Problem is the battery had to keep the voltage above 10.5v at the inverter.

Here is my up date on my economic home made tig welder.

http://ecorenovator.org/forum/attach...1&d=1456071121

This is what it looks like when I use it on stainless steel.

http://ecorenovator.org/forum/attach...1&d=1456071121

I have less in it than what one would spend on the cheapest made in china imitation dog poo, its reliable and has a top end miller WP-17 torch. Sliding core machines like this typically last until some one steals them to harvest the core out of them or some one takes one to the scrap yard because they think its "obsolete".
So the main two things that kill them are ignorance and drug addiction.

How well are the starts on that rig. Without the features that make tigs easier I can see it being a little more challenging to use. I have used the $200 import tig and it's impressive for the price and for most that will use it here and there it's fine and the $400 version has a foot pedal etc. But no ac so no aluminum or at least not much aluminum welds DC.

Not a bad looking weld at all for that machine. The first time I used a flex head torch I thought why do they even make anything else.

I have never used scratch start before this. Always used a miller maxstar 150 and 200 with lift start.
Otherwise its performance is almost identical the $1500 machine on 120v power.
I have AC, I don't know if 60Hz is useable on aluminum, all the AC machines that get used on aluminum produce around 400Hz.

As far as I can tell you really only need the foot controller for aluminum.
I weld a lot of stainless and have never used the foot controller.

I, for one, am VERY impressed with the weld quality. The picture looks great.

Steve

Cool. Great to hear it works that well. Especially on 110v. You don't need the super high HZ for aluminum but it helps. Same with the foot controller but those things are more important for the super thin stuff.

Those old style machines like yours were good machines. My neighbor has a big eutectic tig as that's what he used when he was a welder In a semi trailer shop. Water cooled torch etc. But the transformer had a fire due to the coating on the windings deteriorating. He is going to have a motor reminder look at it and se if it's feasible to rewind. Problem is it takes a forklift to move.

Just never ask me to use an old cracker box. Learned how to weld on one and if you can use it you can use any machine after that. Also learned mig on a miller box with a cobra matic wire feeder. That was bad... Never would keep a steady wire speed.

On the subject of welding aluminum, welding aluminum with DC takes helium which has gotten expensive in recent years and you have to use reverse polarity DC to weld aluminum.
Problem with reverse polarity tig is it puts the vast majority of heat into the welding electrode. The welding electrode gets something like 8 times as much heat running in reverse polarity.
When welding straight polarity the vast majority of the heat goes into the work (80% to 90%).
Mostly balanced organic AC power will not heat up the electrode as much as reverse polarity DC. The electrode might see around 4x the heat as compared to running it straight polarity.
The expensive AC machines can create 400Hz AC power that has 90% of the power on the straight polarity side and 10% on the reverse polarity side.
You have to have at least some reverse polarity to deoxidize the aluminum.

In the past, with welding aluminum you had a choice of using a cheap DC machine with over sized water cooled torch and more pricy helium, or a super expensive AC machine and cheaper argon gas.
In recent years the price of the expensive high frequency AC machines has come way down (but they are still expensive, a few thousand dollars for a good one), the price of helium has gone way up, if you can even get it so almost everyone has gone with more advanced high frequency AC machines that can weld aluminum with cheap plentiful argon.

Now what I cant find any info on is if balanced 60Hz needs argon or helium or a blend, or if it will even work. Since you can weld aluminum with DC+ and helium I don't see why I couldn't make 60Hz AC work unless there is some kind of funky magnetic, hysteresis, eddy current losses going on.

I have 1/8 inch wide Zirconium oxide doped tungsten electrodes that are supposed to be toughest most heat resistant electrodes you can get. Some time soon I will plug the leads into AC put one of those electrodes in my torch put it to aluminum and see what happens.

fwiw, I use 100% ARGON on most everything except mild or carbon steel. If you want pretty and clean, TIG is the way to go, and a square wave machine will do anything you throw at it. A buzz box like oil pan has in his pic will do for anything above about 10 gauge, but for thin sheet, you either have to do little stitches or have some crazy skills. But TIG is inherently slower than MIG.

For high-speed welding at the cost of looking super pretty, you can weld aluminum and stainless and such with a MIG machine, even on DC. The wire you choose must have the right trace elements in it to scavenge the oxygen and hydrogen while the puddle is wet. Also, you have to use separate torches. Iron and aluminum make thermite.

With aluminum, a push-pull torch is nice, but a regular torch will work as long as you keep it clean and don't bend the whip too much. Either way, when welding DC you have to speed through the work, and have a big enough power supply to do it. If you go just a tad bit slower than you should, everything will melt like wax. If the power supply won't source enough amps, you can't move fast enough to stay ahead of the heat.

When joining aluminum or stainless with MIG, be prepared for the sugar and smut to appear, pretty much no matter how much shielding gas you use. Don't worry, the stuff wipes right off after your piece cools down.

The new MIG rigs use pulsed power instead of AC or DC "old school" power. Unless you are doing some super-high speed production or using robots, the pulsed mode is not really all that useful or practical. The only exception to this I can think of is doing full-penetration, vertical uphill welds. I would still almost rather stick weld something uphill than use one of the new rigs. The darn things will fry your eyes through your eyelids like an atomic bomb, but boy are they fast if you get them dialed in right!

I used to have a rig like oil pan's, made from an old battery charger/booster. It was used with everything thin with argon and an air-cooled TIG torch. I tried it with a neon transformer to do the easy-start thing, but it wasn't all that useful to me. I ended up just scratch starting with it. I wired up a toggle switch to the torch for on-off control, and had an alligator clip to jump out the rectifier. It worked and worked until my dad and his gang of pirates scrapped it during a barn cleanout.

To eliminate sugaring I use solar flux or if its a pipe I back purge with argon.
Solar flux is fine as long as you don't care what the back side of the weld looks like.

I removed the cord and replaced it with this.
http://ecorenovator.org/forum/attach...1&d=1457751989

Still working good.
http://ecorenovator.org/forum/attach...1&d=1457751989

Gas saver nozzle and gas lens.
http://ecorenovator.org/forum/attach...1&d=1457752754