Ac/ Dc Ark Welder

[scarecrow]

oops that is .5uf for the ones on the diodes I wasn't too sure of the two on the right-hand side the ones on the same heatsink because the first two I have crossing the heatsink so that all I need to finish the job. There is a good bit of room in the bottom of the welder if it doesn't fit by the looking out for a small mig welder or a big battery charger thats burnt out and put it all into

 

[shenion]

Looked closer, the caps on the left do not need to cross. They should go across each diode then one on the AC in and DC out.

 

[scarecrow]

thank you for all your help shenion i edit the picture on the previous page so I hope it okay now I was just wondering what's the difference between the metal capacitor and a plastic one I presume it has something to do with the heat I'll take a few pictures as I put it together the diodes and reactor arrived today the reactor is a bit of a monster it must have been quite a job to wind the copper wire around the centre when you were making yours im glad I didn't try that

 

[shenion]

Metal caps dissipate heat better. The electrolytic ones you posted initially will boil the electrolyte and literally blow up.

The metal ones are usually made of layers of plastic foil (polypropylene, mica, and others.) They last forever as there is no liquids to dry leak.

My reactor used 1ga welding cable. It is very flexible. Was easy to wind. The multi-strand does not work as well as eddy currents will occur in the wires. The core had to be big, it is about 8" square. If I used solid enameled wire it could have been 1/3 the size.

If I make another, I will use copper tubing or aluminum sheet for the winding. Solid core enameled wire is hard to find

 

[scarecrow]

Made a bit of progress this week

I made up the heatsinks from some bit of a aluminium I had lying around I still have to connect up ac inputs I'm going to take them from the back of the original ac output and I have room for the capacitors in the back lefthand corner then attach the mov's I put 2 new outputs for the dc since my welding cables are plug-in so I should be up and running pretty soon

 

[shenion]

Looks good. I take it the reactor is connected to the two leads from the right two diodes? That would normally be the negative output unless you have "R" version diodes (your diagram shows R version diodes, normally the cathode is the stud unless it is an R version.)

Should work well, I bet the arc will be real smooth.

 

[scarecrow]

The reactor is connected to the two diodes on the right-hand side I will also be connecting the ac imputs to the two heatsinks on the righthand side if you meen reverse polarity diodes as far as I know these four are the same polarity on the diagram i found the positive was from the two diodes on the right there wasn't any markings on the diodes so I'm not sure I did ask them if they had reverse polarity diodes before I bought them and they said no

 

[shenion]

Your drawing shows reverse polarity diodes, the stud side the anode.

With a ohmmeter, they will conduct with the + side of the meter connected to the anode.

If they are normal polarity, just swap the +/- markings on your output lugs.

 

[scarecrow]

I get a reading from the diode with the black lead on the stud which I think is the-
and the red lead on the wire I think the red lead on the ohmmeter is the + because it has a diode symbol beside where it comes out of ohmmeter i get no reading the other way around
does it make a difference which cable the reactor coil is on

 

[shenion]

Ok, so the terminal closest in the pic wil be + and the reactor is on the - lead.

The reactor can be on either side.

 

[scarecrow]

Would the reactor work better on the + I can still changed them around

 

[shenion]

It will work the same either way. If you make the argument that it should be on the electrode side, then when you need to swap polarity it will be wrong. It will work the same on either; I have seen MIGs with the reactor on the work lead simply because it was easier to wire.

 

[scarecrow]

finished putting it together to day


I tried it out and it's working great you're right the ark burns with hissing noise and it's much smoother I'll give it a proper test tomorrow

 

[shenion]

Ok, now you know why cheap welders leave this stuff out and are AC only. Lots of work to wire in, heavy, expensive wire. Not only will it weld better, it will not radiate lots of noise on your power lines. That's more neighbor-friendly.

Well done ; look forward to seeing the results.

 

[scarecrow]

It does take a bit of work to make up and wire in but to be honest I really enjoyed doing it I'm a kind of sad now that it's finished but absolutely delighted with the way it welds I did notice that the end of the run was much flatter than on AC and the you need to turn the welder of a bit higher than usual can I use the ohmmeter to test for amps


Thanks again for all your help couldn't have done it without you I'll post a few more pictures when I get to use it in anger I wish I had a digital camera so I could take close-ups the weld is much better than it looks in the photo

 

[shenion]

Yes it is fun if you like tinkering, I'm enjoying building my own portable.

You will need to figure out the currents as it will be different. The drop across the diodes and the added reactor will lower it a bit. Most AC/DC welders have two scales or two separate taps on the transformer. My Airco has a separate tap for AC that is a bit lower voltage.

Welds look good, you could tell someone they are MIG and they would have no reason not to believe you Look almost spatter free. AC welds always seemed to have spatter.

 

[scarecrow]

I think iv got the tinkering bug I hope I don't come across an old welder somewhere that need repairing I would be very tempted to bring it home and then start bothering you again
I did notice the lack of splatter that peace of the angle iron was pretty rusty which would have produced a lot of splatter which is a nuisance if your welding near treads

 

[shenion]

This kept me busy for about 5 months.

3 old welders, newest was 25 years old. All work as good as new. Major part of restoration was cleaning and repainting. There are the types thatuse things until they stop working then get another. All 3 of these just needed basic maintenance. The Airo had actual bad parts but that was caused by not adjusting the spark gaps.

Now I hope I don't find an old Lincoln Pipeliner, would keep me busy for probably a year

 

[shenion]

I picked up oneof those reactors from surpluscenter. It is bigger than I thought. Will go in my DIY welder.

They screwed me on a new geared motor for a wire feeder. They had one that was the right RPM and a lot of torque; looked like a car window motor. Box arrived today, no motor, "Out of stock"

Will try the reactor this weekend. My hand-wound one used stranded wire so was not ideal. Al least I'll be abe to use the 25' of wire from it as a work lead as it was #1 gauge wire.

 

[knoba]

Way to go scarecrow! That's amazing stuff! Well done guys.

I wish I could get my head around electronics and computer programming. Every time I try, either, I get "no... it's not happening" mental blocks. ...I'll get there one day!