AC vs DC amperage

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When looking at the cracker box style machines, Lincoln, Hobart, Miller etc all of these machines are typically rated at 225AC but only 130-160 DC.  My question is the machine pulling the same 50-60Amps it would need to run 225AC as set at its maximum DC setting?  or does 150AC = 150 DC amperage draw just an issue with saving money on cheaper rectifiers to make the current?Also if I wanted to buy new leads for the machines if I planned to do 95% of my welding on DC would I be able to use lighter gauge cable as 150 amp typically only requires #4 cable out to 50' etc?Also for fun Comparing the lincoln to the Hobart/Miller how much better is the extra amperage in DC and the infinite settings?  Found a like new AC/DC tombstone for $400 or I can get a new hobart stickmate for $470 out the door new.
Reply:By scott;Also if I wanted to buy new leads for the machines if I planned to do 95% of my welding on DC would I be able to use lighter gauge cable as 150 amp typically only requires #4 cable out to 50' etc?
Reply:Originally Posted by scotWhen looking at the cracker box style machines, Lincoln, Hobart, Miller etc all of these machines are typically rated at 225AC but only 130-160 DC.  My question is the machine pulling the same 50-60Amps it would need to run 225AC as set at its maximum DC setting?  or does 150AC = 150 DC amperage draw just an issue with saving money on cheaper rectifiers to make the current?I am guessing the amperage is lost in converting from AC to DC. YGWYPF (yougetwhatyoupayfor)Also if I wanted to buy new leads for the machines if I planned to do 95% of my welding on DC would I be able to use lighter gauge cable as 150 amp typically only requires #4 cable out to 50' etc?Remember, after 50' one way, current must travel another 50' to get back to the source. Heavier cable with short extensions at the working ends are one popular system of cable extensions.Also for fun Comparing the lincoln to the Hobart/Miller how much better is the extra amperage in DC and the infinite settings?  Found a like new AC/DC tombstone for $400 or I can get a new hobart stickmate for $470 out the door new.
Reply:You should check into getting an inverter. Thermal arc has a 161s which also has lift arc for tig and the basic kit you can find here http://http://store.weldersource.com/w1003602.html. I have the TA 185 and it run 6010 with no problems.
Reply:Think an inverter is out of my price range.  And would rather go the traditional route on one of the top name brands than a slightly less brand inverter.Still not sure on the definite answer on the AC vs DC draw.  Does the machine have to work hard to make the DC current giving it the lower DC rating or is it just a shotty rectifier leaving the lower rating?
Reply:I've thought the infinite adjustment found on the Miller crackerbox would be great, but when running 1/8 7018 on DC I usually have to max out the Lincoln at 125amps just to get a nice wet puddle, so the infinite adjustment wouldn't help.Tapped adjustments are ok if you change travel speed to match amps which might be a little high at a particular tapped setting.  Forget about amps really, just watch the puddle and change technique accordingly."Any day above ground is a good day"http://www.farmersamm.com/
Reply:If all you want is a good AC-DC stick welder, there are some older units out there sold by Sears, Wards and probably other companies which often sell for very reasonable prices. Usually they are units used by hobby-welders and have sat in garages for years, often being in very good shape. This thread Here shows one which wasn't taken care of but still probably worked well; note that it was rated 250 amps for both AC and DC. I've seen similar units (but in better condition) being  given away  on Craigslist!
Reply:Thermal Arc is a top brand name, you should go to their website and see what top name brands fall under their company. A few benefits to the inverter would be less amp draw, DC (more rod selection), lift start tig, lighter weight (20lbs) and ability to run on 120v. As far as AC vs DC, in working in the field for four years I've never seen a machine that was able to weld in AC and you also need to remember that with AC the arc has to cross over zero volts 60 times a second. So 125 amps AC is not equal to 125 amps DC being that AC would be colder and also be limited in rod selection. The latest I heard that Thermal Arc offers a five year warranty and the price on the 161s was $624, not to far from $470.
Reply:"I've never seen a machine that was able to weld in AC"  i just sold an old miller thunderbolt that was 225 AC only...I am working with only a 40 amp breaker which is why I was worried that if I had a cracker box style welder than if the DC required more amps to run that i would possibly trip my breaker running an 1/8" rod.  However after reading up on this thread and doing some more research I am going to pick up a Miller Maxstar today.  Getting it for less than I was going to give for the Hobart.  Will weld 150 amps DC which was about the same as I would get out of the Hobart.  Will also have the possibility of hooking it up to our generator and having a ghetto 100% portable welder.
Reply:The reason for the Thermal Arc unit is that the Maxstar cannot run 6010 rod well, but can run 6011, where the ThermalArc unit can run 6010.  I do own a Maxstar 140str which is an older unit and it also has trouble running 6010 rod. If you do get a Miller Maxstar 150s it is only a stick machine and will not do any tig. I work for a company " out in the field" that does repair work on the oil storage tanks at the tank farms and refineries and have never seen a machine capable of AC .