Portable 24v flux core welder

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I tore apart my old POS Harbor Fart 90 amp flux welder, modified the wire feeder speed control a bit, and installed it into an old DeWalt laser level case.  I still have to add a pair of battery leads to it, but it's about done.  Included in the case will be the pair of 10 foot battery leads and a single jumper to series 2 batteries together for 24v.  Inspired by the ReadyWelder battery spool gun system. Last edited by anickode; 03-19-2012 at 10:05 PM.
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Reply:Nice and compact.  Is the wire going to be hot all the time, or will you have a contactor?Miller Syncrowave 350Millermatic 252/ 30A spoolgunMiller Bobcat 225g w/ 3545 spoolgunLincoln PowerArc4000Lincoln 175 Mig  Lincoln 135 Mig Everlast 250EX TigCentury ac/dc 230 amp stickVictor O/AHypertherm 1000 plasma
Reply:I plan to put a 24v starter solenoid in it for a cold tip, but for right now it's a hot tip.
Reply:A starter solenoid will pull WAY more amperage just to close the points than you'll want to waste.  You need a real contactor that uses fine wire on the holding coil. Check Ebay for contactors.  They are cheap.Miller Syncrowave 350Millermatic 252/ 30A spoolgunMiller Bobcat 225g w/ 3545 spoolgunLincoln PowerArc4000Lincoln 175 Mig  Lincoln 135 Mig Everlast 250EX TigCentury ac/dc 230 amp stickVictor O/AHypertherm 1000 plasma
Reply:That is a really neat little idea, espeically you could buy one of those cheapie welders for less then you can a readyweld spool gun one.Ace job!
Reply:Trouble with a contactor is finding one that will handle the kind of current I'm looking for...  I need something that is capable of handling 150 amps or so at up to 36vdc.  The coil must be able to handle a range of about 18-36 volts DC without burning up.  I don't have the option of using a lower amperage contactor on the Line side of a transformer.This is built to run off a couple big *** batteries, so I can't imagine a few amps to pull down a solenoid shouldn't be much of an issue...
Reply:Check out this contactor on Ebay:http://www.ebay.com/itm/GX11CA-150-A...item27bf1d30aeMiller Syncrowave 350Millermatic 252/ 30A spoolgunMiller Bobcat 225g w/ 3545 spoolgunLincoln PowerArc4000Lincoln 175 Mig  Lincoln 135 Mig Everlast 250EX TigCentury ac/dc 230 amp stickVictor O/AHypertherm 1000 plasma
Reply:Explain what the purpose of the contactor is please, I am loving this post, got me thinking about addind a fluxcore pack to my homemade portable welder now!
Reply:A contactor is a type of relay,you use a small amount of current like 2 amps,to close a set of large contacts.Sort of like the starter relay in a car,3 amps through the relay coil, closes the contacts and 300amps flows.By putting a contactor between the battery power and the tip,the tip has no power till you press the trigger.
Reply:Run into a problem... The wire feed controller appears to be a simple PWM...  It draws AC power from the secondary side of the transformer and immediately rectifies it to DC.  SO logic would say that if you were to feed it with DC, it would still function fine.What happens though, is there's almost zero change in motor speed, and once you squeeze the trigger, it starts feeding and won't stop.  I'll probably just replace it with a 12 dollar PWM from ebay, but if anyone has any quicker suggestions, I'm open.
Reply:The speed control is SCR based,the bridge rectifier puts pulsed DC to the SCR,the SCR can only switch off if the DC voltage goes to zero.
Reply:Im diggin this as well. You would have a nice duty cycle 100% if you have a good alt to help the batteries out
Reply:Originally Posted by BlueweldersThe speed control is SCR based,the bridge rectifier puts pulsed DC to the SCR,the SCR can only switch off if the DC voltage goes to zero.
Reply:You could use a variable voltage supply that puts out 2-12 volts,or a pwm supply.The wire feed motor only needs an amp or two at up to 12v.