What causes the arc to go out

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I bought this welder a few weeks ago for $50.00 and after playing with it for awhile I decided to keep it. It's a miller 180 AC/DC stick welder and it runs perfectly on DC but on AC the arc will go out while welding. If I touch the electrode to the base metal it will light up immediately with no problem. It doesn't do it all the time but once in three electrode.I cleaned all connections so the only thing I can think of is the capacitor under the fan might be bad. I changed the leads with new ones so I know it's not them. I tried to ground out the capacitor and nothing happened. All connections were also cleaned with contact spray along with emery cloth before reconnecting.Any help is appreciated. Attached Images
Reply:Originally Posted by kctgbI bought this welder a few weeks ago for $50.00 and after playing with it for awhile I decided to keep it. It's a miller 180 AC/DC stick welder and it runs perfectly on DC but on AC the arc will go out while welding. If I touch the electrode to the base metal it will light up immediately with no problem. It doesn't do it all the time but once in three electrode.I cleaned all connections so the only thing I can think of is the capacitor under the fan might be bad. I changed the leads with new ones so I know it's not them. I tried to ground out the capacitor and nothing happened. All connections were also cleaned with contact spray along with emery cloth before reconnecting.Any help is appreciated.
Reply:Originally Posted by MWaldenYou might want to include what exact electrode you were using and what metal you were using it on.  Not all electrodes run well or at all on AC and vice versa.
Reply:Originally Posted by kctgbI was using 6013 and 7014 on AC and 6010 and 7018 on DC. I've been welding since 1979 so I know what runs well on AC and DC. I don't think that's the problem. The base metal was 1/4 mild flat stock. I tried different base metal and it ran good on DC but did the same thing on AC.
Reply:Originally Posted by MWaldenGot it.  I meant no offense but you never know.
Reply:If I remember correctly, your machine has a high and low range for AC.  Is that correct?  The Low range has a higher OCV and tends to reduce the tendency for the arc to go out. (I know that sounds wrong but you can verify the higher OCV with your multimeter)Just to cover the bases - what size 6013 and 7014 and what amps were you running each at?Did you try the same electrodes on a different machine recently?Dave J.Edit:  I've checked a few AC machines with High/Low ranges and it's been the same each time.  Low range has higher OCV, and it's about as high as on the standard Lincoln tombstone AC machines.Last edited by MinnesotaDave; 07-22-2013 at 12:17 AM.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Originally Posted by MinnesotaDaveIf I remember correctly, your machine has a high and low range for AC.  Is that correct?  The Low range has a higher OCV and tends to reduce the tendency for the arc to go out. (I know that sounds wrong but you can verify the higher OCV with your multimeter)Just to cover the bases - what size 6013 and 7014 and what amps were you running each at?Did you try the same electrodes on a different machine recently?Dave J.Edit:  I've checked a few AC machines with High/Low ranges and it's been the same each time.  Low range has higher OCV, and it's about as high as on the standard Lincoln tombstone AC machines.
Reply:Only time I'll lose arc is if the power plug gets too corroded from being outside.  The machine shuts down at the same time.Using an outdoor drop not really meant to be outdoors causes my problem, and I usually just clean up the connections and go on my way.  It's mostly where the copper wire connects with the lugs on the receptacle."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by farmersammOnly time I'll lose arc is if the power plug gets too corroded from being outside.  The machine shuts down at the same time.Using an outdoor drop not really meant to be outdoors causes my problem, and I usually just clean up the connections and go on my way.  It's mostly where the copper wire connects with the lugs on the receptacle.
Reply:I'm not expert, but could it be a duty cycle issue? possibly a bad component in that causing the machine to cut out under AC?There are no problems. There are only solutions. It's your duty to determine the right one.Hobart Handler 210Airco 225 Amp MSM Stinger
Reply:Originally Posted by ThorsHammerI'm not expert, but could it be a duty cycle issue? possibly a bad component in that causing the machine to cut out under AC?
Reply:thats fine, but is there an overload switch or something that causes it to turn off if it exceeds the duty cycle that could be faulty and causing it to turn off below the actual duty cycle.There are no problems. There are only solutions. It's your duty to determine the right one.Hobart Handler 210Airco 225 Amp MSM Stinger
Reply:Originally Posted by ThorsHammerthats fine, but is there an overload switch or something that causes it to turn off if it exceeds the duty cycle that could be faulty and causing it to turn off below the actual duty cycle.
Reply:Most 50.00 welders have a glitch. But my question is that if you have a DC welder why would you ever put it on AC for stick welding? I have AC,DC on my idealarc 250 and for the life of me cant figure why I would want to try to weld with AC again. Had enough of that over the years in different shops I worked in learning to weld.  I dont have AC on my sa200 and dont miss it. I would leave it on DC and weld weld weld. Have a good day and God bless.
Reply:Originally Posted by kctgbI can't find any switch for an overload.
Reply:Originally Posted by kctgbYou are correct about the OCV. I was using 1/8 rod and I haven't tried it on another welder yet. I tried running it from 100 amps all the way up to 150 amps. Amp setting makes no different.Any other ideas ?
Reply:I've seen Lincoln 225's do the same thing, push them hard and they fizzle out on their own.Drop the rod and immediately put in a new one, takes right off again.Everyone says that is because you are exceeding the Duty Cycle.Those low end machines do not have thermal switches to prevent you from exceeding the "Duty Cycle".You are right about the Dial-Arc size machines, you can run them till they burn the house down!HA! HA! HA!
Reply:Originally Posted by Welderskelter But my question is that if you have a DC welder why would you ever put it on AC for stick welding? I have AC,DC on my idealarc 250 and for the life of me cant figure why I would want to try to weld with AC again.  I dont have AC on my sa200 and dont miss it. I would leave it on DC and weld weld weld. Have a good day and God bless.
Reply:The AC on your Bobcat could still be useful for TIG in the field, with an HF box, I would think.Everlast PA160-STH... and that's about it!
Reply:I have the Airco 180.  Looks the same, except for the paint.If mine was doing this, I would suspect the AC output plug/recep. connection. The DC works, so the rest of the machine should be OK. Intermittent connection/arcing ?  Seems like it's making just enough of a connection to weld until it heats up a little. To test- Open the welder and bypass the connector and try it...that's what I'd do. Great little welder...I hope you fix it.
Reply:Originally Posted by WelderskelterMost 50.00 welders have a glitch. But my question is that if you have a DC welder why would you ever put it on AC for stick welding? I have AC,DC on my idealarc 250 and for the life of me cant figure why I would want to try to weld with AC again. Had enough of that over the years in different shops I worked in learning to weld.  I dont have AC on my sa200 and dont miss it. I would leave it on DC and weld weld weld. Have a good day and God bless.
Reply:Originally Posted by MinnesotaDaveStill sounds like low OCV because it stops jumping the gap even while welding in low range.Does it still pop out if you use a light drag? (flux touching the metal)I would check the OCV with your meter.  55 volts on high range, 80 volts on low range.  I'm interested in what numbers you find.I base those numbers on this file: http://www.millerwelds.com/om/o114a_mil.pdfIs that the right manual?Dave J.
Reply:Can't find a manual on the AC/DC version of that on Miller's site. It would appear that the big cap is for power factor correction and, if so, could possibly be disconnected to eliminate that as a source of problems.  However, it's there on either AC or DC.I do note from some front panel info on a similar welder that the OCV on the DC side is about 56 vs. either 55 or 80 on the AC side, in case it matters where they hooked things up. Recheck the AC/DC switch contacts."USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:Originally Posted by kctgbSometimes AC comes in handy as I live in farming country and a lot of stuff that has been out in the field has a magnetic field..
Reply:I put a volt meter on the large box under the fan and some strange readings came from it while the welder was turned on. They were negative voltage readings on both AC and DC. I'm going to disconnect the box and see how it welds.*It's not the welder just ran some rod in the thunderbolt and half way through the third rod it went out.I'm using Hobart 6013 and 7014 on AC.Wondering if it's a circuit issue like a faulty breaker. Checked the breaker and it's not hot.Anyone have any ideas.
Reply:I don't know a complete answer to you question, but there has to be sufficient voltage to drive an arc across the gap between electrode and workpiece (it takes a minimum amount of energy to ionize the gas in that space). This voltage increases with distance. Maybe fleetingly, you are exceeding maximum distance possible for your voltage? Maybe good to have somebody else try welding a few 6013/7014 on your Hobart to seeLast edited by wirehead; 07-23-2013 at 07:57 PM.XMT304 (school)SP125+ (home)HF 4x6 BandsawGood judgement comes from experience and much of that comes from bad judgement.
Reply:Originally Posted by wireheadI don't know a complete answer to you question, but there has to be sufficient voltage to drive an arc across the gap between electrode and workpiece (it takes a minimum amount of energy to ionize the gas in that space). This voltage increases with distance. Maybe fleetingly, you are exceeding maximum distance possible for your voltage? Maybe good to have somebody else try welding a few 6013/7014 on your Hobart to see
Reply:Originally Posted by kctgbI put a volt meter on the large box under the fan and some strange readings came from it while the welder was turned on. They were negative voltage readings on both AC and DC. I'm going to disconnect the box and see how it welds.
Reply:Originally Posted by kctgbCould be the problem but I have never had a long arc problem in 34 years of welding. I'm looking more at the Hobart electrodes as my other welders run fine on the same circuit.
Reply:I won't be able to run some different rod until next week but will let everyone know the results.Thanks everyone for the help.
Reply:Well, your OCV wasn't the problem, so that's good.  Welder probably functions normally.Sounds like you've narrowed it down to the rods?  That's good - simple fix is always good   I bought some Hobart 6013 last year that really suck - run ok but spatter terrible!!If that does not fix it - could be a wiring problem.  About 10 years ago I had some crazy stuff happening in the shop - turned out I had a loose neutral out at the pole.  (All three buildings have their main lines hooked at the pole in the yard - standard country living set-up)Dave J.Last edited by MinnesotaDave; 07-23-2013 at 11:44 PM.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.