Any Welders in the crowd?

banjoman09 · Aug 10, 2017

If it is ok....Ill post a different subject. I have "welded" most of my life...not great at welding but I get by with what I need to do. I bought a "CBR" welder at an auction a few yrs back - has worked great til yesterday. It is a 250 Amp buzz box - AC_DC and I usually just weld on "AC" but yesterday it started "stalling out" on AC- would weld ok for 30 secs. then stop- rest for a little bit then start again...kept doing that. I took the cover off and checked it out- had a loose connection one time and fixed it but didn't really find anything this time. I switched the leads to "DC"...works fine this way. I'm not sure what "DC' is as opposed to "AC"....any ideas on fixing the problem? (trash it?) Thanks!

old · Aug 10, 2017

I do not know the machine as such but sounds like you may have a poor connecting at the adjustment switch area if it has that. Been a while since I did welder repair but back when I worked at Tracker Marine I sure did fix a ton of them over the years.

The Dukester · Aug 10, 2017

I was just a maintenance weldor, but in my limited experience I felt I could get better "puddle control" and better looking welds using DC reverse polarity, if DC reverse rod was available and suitable. But I found AC or DC straight polarity may give better penetration sometimes and start a little easier. In our shop we had an old Hobart MG set welder that would help you lay really pretty welds using D.C. Reverse rod, but for "quickie" jobs out in the production and furnace areas we often just used a Lincoln 225 AC buzz box and never switched leads to get DC.
In DC mode the electrons run from the stinger to the workpieces one way, in straight polarity from the workpieces to the stinger in reverse polarity......With AC the electrons (or current flow) run both ways....That's how it was explained to me anyway. Our fancy TIG welder had a low voltage AC auxiliary mode to help start while using DC reverse mode to make the ball on the electrode off a stainless blank for aluminum welding and straight polarity for the actual welding of the aluminum or while using a parallel ground pointed electrode doing ferrous metals (steel and iron alloys). IIRC.

banjoman09 · Aug 10, 2017

thanks to both of you....and I will check that...I have looked at connections but feel maybe Im missing something. Thanks.

old · Aug 10, 2017

On my old Lincoln buzz box I have had the adjustment setting part and where it moves get corroded up badly and cause odd problems

Welding man · Aug 10, 2017

I have been in the welding business for over 40 years, but when a machine breaks down or quits working, other than something simple, I send it someone that has a lot more electrical experience than I do. I try to be a an expert welder not an expert electrician.Most really good welders that I know,don't have a clue how to fix a welding machine.

MarkB_MI · Aug 10, 2017

When you weld with DC, you're using all of the AC section of your welder. But when you weld on AC, you're using none of the DC section. So about the only thing that might be bad is the AC/DC switch.

Alternating current switches direction 120 times per second. Direct current always goes in one direction.

What the DC section of your welder does is to rectify the alternating current output using solid-state rectifiers. The "DC" output isn't truly DC, it's actually full-wave rectified AC. But at any rate, if the welder is working on DC, the AC circuitry just about has to be good.

banjoman09 · Aug 10, 2017

Wow....right over my head! lol...you do know your electricity- great. The "AC" has two plug-ins and the "DC" has two plug-ins ; no switch. However, from what your saying the AC should work. Hmmmmm ...thanks.

banjoman09 · Aug 10, 2017

yes....me also. But I try to fix anything before I pitch it. Thanks.

banjoman09 · Aug 10, 2017

ok....Ill look closer; wouldn't that affect both sides?

old · Aug 10, 2017

120 time a second?? It is 60 cycle current so shouldn't that be 60 times per second???????

old · Aug 10, 2017

That would all depend on how it is wired up so as the switch the amps in it. Could have one tap of the transformer going bad so work some times and not others

Kellyss · Aug 10, 2017

You are correct. The US is 60 Hertz or 60 times per second.

docmirror · Aug 10, 2017

(quoted from post at 14:05:20 08/10/17) You are correct. The US is 60 Hertz or 60 times per second.

No, you were right the first time. 60Hz 'switches direction' 120 per second. The first quarter phase is up, then from the + peak to the - peak(2nd and 3rd quarter phase) it is going down(1st change), then from the - peak back to 0deg it is again going up. Or, if started from 90deg at plus peak, one could say it crosses the zero phase line twice.

As for the welder, if it's hot, you may be just overheating it. Most big sparky welders have a large fan, make sure that's turning. There should be vents in the case, and make sure they are not covered or clogged.

All old sparky welders have a 'duty cycle'. The duty cycle decreases with rise in amps. That means you can weld for x seconds, then idle for y seconds. If you are using a high amp load this could be the duty cycle limitation, although that would be typically affecting both AC and DC.

Smell the unit right as it stops putting out current, tell me if you smell hot lacquer, or a burning plastic kind of smell. That would be a breakdown of the transformer wire shellac (junk if so).

MarkB_MI · Aug 10, 2017

I thought you were an electrician in the Navy.

Each cycle includes two reversals. Positive-to-negative and negative-to-positive.

old · Aug 10, 2017

Do not insult me like that i was not an electrician in the Navy I was an electronics tek as in computer repair but shoot that was 37 plus years ago and working with electric is something I have long since got out of

banjoman09 · Aug 10, 2017

ok....I guess I will just weld on "DC" until it shoots craps. Thanks.

banjoman09 · Aug 10, 2017

You guys are like really getting into this...lol...amazing...but I will check these things in the morning...thanks!

banjoman09 · Aug 10, 2017

Okay.....everyone is trying to help; lets keep it calm please...was just asking for ideas for a fix- not the chemistry of the welder....so thanks to both of you.....

MarkB_MI · Aug 11, 2017

> f you are using a high amp load this could be the duty cycle limitation, although that would be typically affecting both AC and DC.

You might have something there. Many AC/DC welders are significantly derated for DC.

docmirror · Aug 11, 2017

(quoted from post at 03:33:55 08/11/17) > f you are using a high amp load this could be the duty cycle limitation, although that would be typically affecting both AC and DC.

You might have something there. Many AC/DC welders are significantly derated for DC.

His fault condition seems to be only on AC, but works ok on DC. I would inspect the conductor path carefully for the AC side. From the transformer out to the AC connection lug. Clean everything with a can of De-Ox-It, or use some crocus cloth on the lugs for the cable and the receptacle in the welder.

banjoman09 · Aug 11, 2017

ok, I will unplug welder(ofcourse) and follow the AC leads(wires) and loosen nuts and clean all surfaces.... I did check the fan and it is running....thanks for your help.

banjoman09 · Aug 11, 2017

and I don't think it was "heated" ; I only weld about 10-15 mins. at a time on 120 amps...... 1/8 rod.

Any Welders in the crowd?

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