Welding polarity

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I need some help.  I just bought an older Millermatic 200 mig machine. I am going to weld steel for practice.  I think that I want the machine set to Electrode Positive.  To do that do I put the twistlock plug on weld cable from the unit into the + positive output and put the cable with the ground clamp into the  - negative output receptacle?I hope this makes some kind of sense.I just want to practice before my welding class starts.Thanks for all your help!!Jeffrey
Reply:Sounds like you have a second generation or later MM200 as the polarity can not be switched on first generation machines.  At least not without modifications to the machine.To answer your question though, yes, what you described IF you plan on using the MIG process with solid wire and shielding gas.  To use fluxcore (without gas) you would use straight polarity where the electrode (gun) is negative and the work clamp is positive.Obviously you will also need to insert the RANGE connector in either the LOW or HIGH receptacle based on the required voltage range for the material being welded.  The unit manual or chart on the inside of the feeder access door will give you basic guidlines to work from for "dialing in" your settings for a particular material, wire size, position, etc.If you don't have a manual you can download the .pdf file version here http://www.millerwelds.com/service/o...uals.php?model by entering the unit SN, select Millermatic 200 and click Search.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:Thanks Duane55.  Yes,  I am running solid wire with 75/25 gas.  The hi and low and wire speed I will just play with.  There is a chart on the inside of the wire access door to ball park it. I just need information on the polarity issue.  Easier to ask than get frustrated. Thanks for your help!!Jeffrey
Reply:Don't know about your 200 but my MM 175 has polarity settings on the inside of the door.                                                MikeOl' Stonebreaker  "Experience is the name everyone gives to their mistakes"Hobart G-213 portableMiller 175 migMiller thunderbolt ac/dc stick Victor O/A setupMakita chop saw