Transformer Oil

We still have three or four 25 litre barrels of this oil available if anyone still needs some....

Peter

-- Peter A Forbes Prepair Ltd, Rushden, UK snipped-for-privacy@easynet.co.uk

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Prepair Ltd
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Peter,

Is it straight mineral oil, or the older stuff that used pcb's ?.

Quite usefull stuff for high voltage work as well...

Chris

Reply to
ChrisQuayle

It is the correct oil for trannies, welders etc. PCB's were outlawed back in the

1970's IIRC.

I have a Shell reference on a can at home if you need it.

Peter Peter

-- Peter A Forbes Prepair Ltd, Rushden, UK snipped-for-privacy@easynet.co.uk

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Prepair Ltd

Peter - Thanks. I don't actually need any right now, but it could be usefull to have around for future projects, high voltage work, transformer cooling etc. The shell reference would be useful, if its not too much trouble to find it.

The reason I asked about pcb's is that there is still probably quite a bit of kit around with it in, Parmeko style C core transformers and ex mod kit, for example. Apparently, it's properties are still far better than straight mineral oil, much like lead based primer is better than the stuff sold now.

Is this beer tokens, or serious money ?...

Chris...

Reply to
ChrisQuayle

Parmeko C Core trannies were vacuum impregnated with varnish, there's no PCB material in them AFAIK, unless there were some ginormous models they made.

Oil is free to collector, it came out of our PCB (Printed Circuit Board) company transformer when they closed down, it had been renewed fairly recently and was too good to chuck.

Oil is Shell Diala BS148/1984

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

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Peter A Forbes

Peter - Will collect some, if you could suggest a suitable time, or email off list to: syseng at gfsys.co.uk. I think you are near Northampton, so not too bad from Oxford. As you say, too good to chuck and usefull just to have some in stock. Can do swap, whatever, if there's anything you need.

Just for the info, the Parmeko C core trannies came in two main types. The first was open frame vac varnish impreg, with another type using the same basic frame, enclosed by two steel half shells bolted to the ends and then soldered in the middle, with ceramic feed throughs on the ends for connections. The whole thing was filled with tranny oil, with the small fill hole soldered over. Still have quite a few here from junk stripdown / the old valve days and some are of an age where pcb's are quite likely, but fine so long as you don't break the seal. They really were the rolls royce of transformers at the time and too good to throw away even now...

Chris

Reply to
ChrisQuayle

I have one of they, didn't know it was also oil filled...

Postcode is NN10 0JT, 01933 356666 let me know when approx.

Peter

-- Peter A Forbes Prepair Ltd, Rushden, UK snipped-for-privacy@easynet.co.uk

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Prepair Ltd

Safe enough if mounted on a chassis, but if loose, easy to crack the ceramic on those KLG Corundite seals, expecially when the HT winding has 3 tall seals and the other windings the standard 800V ones. If I was using one today I'd mount it terminals up, just in case. Definate possibility of PCB inside.

They're in demand from the valve amplifier hifi kids, anything that will power a pair of Williamson amps. Main problem is that many of them are noisy, just a soldered up banding strap around the C cores.

I sold most of mine to a guy advertising in ukra a few years back, got

25 quid a throw, I'd rather they be put to good use than be door stops.

Regards,

David P.

Reply to
David Powell

Most were mounted through the chassis in commercial equipment, but they do require quite a bit of drilling and filing if you don't have the correct punches. The best solution is to make up a one time drill jig from 10-14 swg sheet metal for pilot holes, then you can get all the holes in the chassis clean and exactly right. I can remember quite a bit of high quality (of the day) test gear, Solartron for example, using these transformers and of course, the MOD used them by the truckload, especially high frequency / 400Hz versions. The C cores effectively made a toroid when clamped, improving efficiency, the steel can reduced magnetic leakage and the oil cooled the windings. Before the days of toroidal winding machines, but C core was a very good system. As for noise, don't remember any such example - the banding strips used a special tool to apply the tension, with the strip folded over, tapped flat and soldered with tension applied. The cores are then clamped by the sides of the internal frame. The oil tends to apply damping and I would be quite suspicious of any which can be heard at all.

Used to work for Belclere in Oxford in the late 60's - not much C core stuff, but well remember the procedures...

Chris

Reply to
ChrisQuayle

My holes looked a bit like the outline of the Olympic logo. Just sufficient overlapping cuts from a Q-max octal valveholder punch.

Yup, that was the way we made them. The joint is unlikely to move, but the band stretches over time. It was a big problem for us with magnetic amplifier cores ~2kVA where the air gap is critical. It could take half a day to shim out the airgap, test (plot b-h loop), reshim, etc, but you got it right and shipped it off to the shops. A couple of years later it came back for reshimming.

My old Solartron scope (the one with the ten turn pot in the middle of the front panel) really hums now, but it must be sort of 45 years on.

Brush Research Division, early 60s. Kept us student & grad apprentices out of mischief. I did enjoy shooting dead 12AT7 out of

7/8 id pipe with shop air. :-)

Regards,

David P.

Reply to
David Powell

Hmmm, 12AT7, was that one or both triodes faulty ?.

Remember that sort of thing well - a favorite at one company I worked for was to drill and ream a piece of 1/2" silver steel bar, ball bearing size and then use it as cannon to fire ball bearings with firework black powder. Never did any serious harm, but you would locked up for years for that sort of thing now. Definately lacking in sense of humour, the modern world and one could just imagine the list of possible charges...

Chris (Sometimes with arch mode on :-)...

Reply to
ChrisQuayle

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