Problem with old-syle oil-imersed arc welder

[orion.osiris]

Hi all,

I think the arc welder I have may be faulty. It's an old Olympic one from t he early 80s and looks indistinguishable from an Oxford of the same vintage and amperage. This thing can run off 3 phase or single and I have it hooked up to the 230 v mains just for test purposes. The input connectors are marked: 415V, 400V , 230V, 0V and earth. I've connected the mains live to the 230v terminal, t he nuetral to the 0V one, and earth to earth. It hums reassuringly when pow ered up, but there's no output voltage present at all so far as I can see, for either the 50V or the 80V outputs. Is there something obvious I've overlooked here? Should I short the unused inputs together, for example? Or tie 'em to ground? How likely is it that t he secondary winding in something this substantial could fail? Looks like I 'm gonna have to take the lid off, but I thought I'd run it past you guys f irst, just in case there's something else I should check first...

thanks.

[Harry Bloomfield]

[e-mail] wrote on 16/07/2013 :

I would expect there to be some sort of output regualator on it, which varies the tapping point continuously, via a large adjusting know, moving a brush along the taps. Maybe the brush has disintegrated actual windings are unlikely to fail. Have you checked the outputs with a meter?

[Bob Minchin]

With reference to you considering running this welder from a converter. It will not work at all. What you have is a single phase welder that can run from SINGLE PHASE either 415v, 400v or 230v. It is NOT a three phase welder and never will be.

Your suggestion about connecting the other inputs together really shows that you are a danger to yourself and maybe others too. Zero knowledge is a very dangerous thing!

[orion.osiris]

It's not that kind of output control, Harry. It's not continuous but comes in discrete 5A steps between 25A and 300A according to the 'combination' se tting of two large spring-loaded pointers that you have to pull up, twist t o the required setting and let back down again. My decent DVM has picked a rotten time to go awol; I'm having to use a cheap analogue Draper, which is n't very sensitive at all. Nevertheless, it should be totally fine for meas uring such an ultra low impedance source!!

[orion.osiris]

om the early 80s and looks indistinguishable from an Oxford of the same vin tage and amperage.

230v mains just for test purposes. The input connectors are marked: 415V, 400V, 230V, 0V and earth. I've connected the mains live to the 230v termina l, the nuetral to the 0V one, and earth to earth. It hums reassuringly when powered up, but there's no output voltage present at all so far as I can s ee, for either the 50V or the 80V outputs.

sed inputs together, for example? Or tie 'em to ground? How likely is it th at the secondary winding in something this substantial could fail? Looks li ke I'm gonna have to take the lid off, but I thought I'd run it past you gu ys first, just in case there's something else I should check first...

Do try to keep up, mate. I've already binned that idea following the explan ations I received here. The problem under discussion now is arising from th e thing being powered up from a 230V single phase source.

[John Rumm]

I don't have an answer to your question, however do recall reading that the Olympic and Oxford brands are owned by these folks:

Might be worth running your query past them...

[orion.osiris]

Thank you, John. I'll keep that in mind...

[news]

I still remember collecting my 200A oxford with starter pack from that address, 40 years ago.

AJH

[harryagain]

I think the arc welder I have may be faulty. It's an old Olympic one from the early 80s and looks indistinguishable from an Oxford of the same vintage and amperage. This thing can run off 3 phase or single and I have it hooked up to the 230v mains just for test purposes. The input connectors are marked: 415V, 400V,

230V, 0V and earth. I've connected the mains live to the 230v terminal, the nuetral to the 0V one, and earth to earth. It hums reassuringly when powered up, but there's no output voltage present at all so far as I can see, for either the 50V or the 80V outputs. Is there something obvious I've overlooked here? Should I short the unused inputs together, for example? Or tie 'em to ground? How likely is it that the secondary winding in something this substantial could fail? Looks like I'm gonna have to take the lid off, but I thought I'd run it past you guys first, just in case there's something else I should check first...

thanks.

The problem must be related to the secondary side as it's humming. First. if it's "oil cooled" chuck it out as it is very like highly carcinogenic PCB. There is a whole raft of regulations for dealing with this stuff it is reckoned so dangerous. Even tipping it is illegal. Do NOT get this oil/fluid on you.

Check out the leads/clamps, it may only be a faulty lug. Next. if the control knob turns multiple times it works by winding the iron core in and out of the transformer, simple mechanical thing. If the control knob turns less than 360deg there will be a series of contacts connected to tappings in the secondary of the transformer. There will be some sort of spring that presses a brush against the contacts. Likely the spring is defective.

[orion.osiris]

Well everything gives you cancer nowadays, it seems. I come from a less timid generation where we don't get obsessed with 'elf & safety. I'll wear latex gloves, but that's solely to do with the desire to avoid getting mucky than anything else. I'm about to commence taking the thing apart and will report back here my findings in due course....

On the plus side, my DVM has started working again! :)

[orion.osiris]

OK, I found the problem.

I used a mobile crane to lift off the lid. *All* the electro-mechanical con tents are bolted to the underside of the lid on this model, so you can actu ally remove the complete workings from their oil bath with no difficulty (a ssuming you have some means of handling the weight involved). The fault was immediately apparent. This type of welder has course and fine amperage adjustments as detailed elsewhere in this thread. The contacts of the course adjustment were virtually mint in their almost Victorian splend or. The fault was with the fine adjustment. Both adjustments rely on exactl y the same system: transformer tappings determined by the movement of point ers described elsewhere on this thread. On the business end of the pointers ' shafts down below the oil level, there's a contact in the form of a coppe r blade about 2mm thick which engages between the slot of a four-way range of springy copper receptacles. On the fine adjustment described, there is u nmistakable evidence of heavy arching and charring during previous operatio n which to fix up goes beyond what a mere clean-up and re-profile would ach ieve. I want to rescue this beast. There's nothing like an oil-cooled arc welder for tackling the real heavy jobs and despite their weight, you just can't b eat 'em. So the question now is.... - please take note those here that dip into threads without reading the background first - .... where in the UK ca n I get oil-cooled arc welder spares, or if not that, then 1mm and 2mm thic k copper sheet I can trim, bend and fit myself?

cheers.

[orion.osiris]

Oh yeah, I meant to say in the previous post (for the benefit of our rather annoying pedants) that when the fine adjustment is shorted out, I get the expected 50 and 80V across the secondary which tends to support my hypothes is that the fine adjustment is f***ed in the manner previously described.

[Tim Lamb]

In message , [e-mail] writes

Might this not be Beryllium Copper rather than plumbing stuff? Softens with heat and loses the springiness.

[harryagain]

wrote in message news: [e-mail]... OK, I found the problem.

I used a mobile crane to lift off the lid. *All* the electro-mechanical contents are bolted to the underside of the lid on this model, so you can actually remove the complete workings from their oil bath with no difficulty (assuming you have some means of handling the weight involved). The fault was immediately apparent. This type of welder has course and fine amperage adjustments as detailed elsewhere in this thread. The contacts of the course adjustment were virtually mint in their almost Victorian splendor. The fault was with the fine adjustment. Both adjustments rely on exactly the same system: transformer tappings determined by the movement of pointers described elsewhere on this thread. On the business end of the pointers' shafts down below the oil level, there's a contact in the form of a copper blade about 2mm thick which engages between the slot of a four-way range of springy copper receptacles. On the fine adjustment described, there is unmistakable evidence of heavy arching and charring during previous operation which to fix up goes beyond what a mere clean-up and re-profile would achieve. I want to rescue this beast. There's nothing like an oil-cooled arc welder for tackling the real heavy jobs and despite their weight, you just can't beat 'em. So the question now is.... - please take note those here that dip into threads without reading the background first - .... where in the UK can I get oil-cooled arc welder spares, or if not that, then 1mm and 2mm thick copper sheet I can trim, bend and fit myself?

cheers.

The "Oil" is very likely not oil and is very dangerous. So dangerous that there are only two place in the country can dispose of it (by incineration.)

Look at the last item here.

You could be locked up for even taking the cover off this thing. You are putting yourself and your family at risk. Why are you such a half wit?

[Chris J Dixon]

Whilst it is certainly true that PCB was used in some transformers, it was never universal, and you have no evidence that there is any in this particular transformer.

Chris

[orion.osiris]

I've just spoken to the MD no less at Youngs (the link some helpful person pointed me to elsewhere on this thread. He has a message for you. He says y ou're talking "absolute rubbish" and should "go boil your head". The oil in this transformers is entirely benign, you can eat chips fried in it, he re ckons. You are getting mixed up with some weird synthetic shit that was all the vogue 40 years ago in the electrical distribution industry and was nev er used in these welders with which he has been personally and intimately a cquainted for over 50 years, so I suggest you get your facts right before i ndulging in personal abuse and outrageous scaremongering. End of.

[orion.osiris]

Just to tie this up, I've been on to Youngs (the manufacturers of Oxford/Ol ympic welders)and ordered replacement components to put this thing back int o fully working order. Not cheap, these high quality English-made parts, bu t it'll still be going in another 30 years and will be perfectly happy to w ork flat-out for as long as needed. Something you can't claim for your crap py chinese inverters and turbos.

[Huge]

It's harry. Just killfile and forget him.

[The Natural Philosopher]

Exactly, as a general rule, like anybody advocating renewable energy, you can more or less guarantee that everything he says is, if not an outright lie, so much a distortion of the truth as to be useless.

[Nightjar]

...

But that is Harry's stock in trade.

Colin Bignell