transformer oil

Mineral oil.

Jonesy

Motor oil usually contains a complex series of additives, which might or might not be compatible with electrical applications.

I certainly wouldn't want to buy mineral oil in quantity in the sort of pint bottles you find at a pharmacy... too expensive that way. The least expensive place to get pure mineral oil is probably a veterinary supply store. It's used as a laxative for animals. The cheapest online price I see in Google is under $11/gallon, which is reasonably competitive with motor oil.

Food-grade and animal-grade mineral oil would lack the possible toxicity issues which might come with the additives in motor oil.

If you want to go cheaper, get hydraulic oil. It is about 10 wt (bit thinner than 30 motor oil) but has virtually no additives.

Cool, thanks, I ought to be able to find that locally. The thing I'm trying to avoid is shipping, these days it will double the cost of a gallon of oil which is irritating.

A lot of motor oil is totally synthetic now. I wonder what the electrical and RF characteristics of it are like, compared to traditional motor oil. Does this synthetic stuff have all of the cling enhancing additives and whatnot in it, or is it formulated to be superior in this respect in the first place ? In fact just what *is* it made of ? It seems to stay an awful lot cleaner than 'real' engine oil. I have used conventional stuff for cooling a high power RF dummy load, and have not had any high voltage issues with it. It would be interesting to do a microwave oven test on both normal and synthetic motor oil to see how bad they are at absorbing RF.

Arfa

While getting a little off topic

It does seem to hold up better. I run it in my cars, it makes a difference, especially in the one with the old oil cooled turbo, that thing glows orange when worked hard and would cook conventional oil dark black in 3K miles, now I run synthetic for 5K and it's only brown by the time I change it.

ha I know some one that owns a dodge Ram that now should have well over

After the first 5k miles or so, he started to use 100% synthetic oil, and all he does at oil changes is replaces his filter and adds to what ever he loses in the process. He has well over 100K doing this. His engine sounds like new still and has never had any thing done to it other than normal things that break down like starters, alternators, belts, hoses etc..

:Will ordinary 10w30 motor oil work ok as transformer oil? This is for some :HV experimenting, not any sort of commercial or permanently installed :product. It's thermally stable and not particularly flammable, but I don't :know how the various additives affect the insulating properties. Is there a :better choice that I can pick up locally for a reasonable price? :

Perhaps you should first do some reading on the properties of transformer oil before making an arbitrary decision to use automotive grade oil in your transformer. The old and venerable J&P Transformer Book has good information on this subject. Using the wrong oil may compromise your transformer - and your insurance if it bursts into flames.

Long url so watch line wrap.

Hey that looks like a pretty handy book.

LOL as for insurance, if they saw the "transformer" in the first place, they'd probably crap a brick sideways. I think the oil bursting into flames is the least of my worries with this unarguably dangerous concoction. At any rate it will never be used for more than a few tens of seconds at a time, and only while closely supervised. What fun is life without a little risk of being vaporized?

nd

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ny

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How about giving us a little bit more of a clue as to what you're hatching!

Don't you have a oil wholesaler or transformer shop in your area? Sometimes a call to your electric company can get you a quart or two from the bottom of a 55 gallon drum for free. They have to top off and change the oil in large transformers from time to time and buy it in bulk. The last time I needed some, I got it from the R&D lab at a local Steel mill, in Ohio.

The alternative would be winding my own transformer, but I already have a pile of MOTs and they were free.

Yes, the output from this thing would be absolutely lethal if touched, do not attempt this at home.

That's another thought. There's probably one out in downtown Seattle somewhere, most of those sort of places are only open during the 9-5 period I'm at work so it's probably easier to just mail order it unless I can find something suitable at a hardware store or something else local that's open evenings or weekends.

If I wasn't going to the trouble to find transformer oil, which is mineral oil based with a high flashpoint, my 2nd choice would be mineral oil as somebody else stated, 3rd choice would be automatic transmission fluid before using motor oil. The detergent properties of motor oil which keeps contaminants in suspension could compromise it's insulating qualities.

No, most of it is still petroleum-based. But almost every oil company has a synthetic product.

Why don't you just find a company dumping its PCBs in the local lake, and pick up some?

---- The Lady from Philadelphia

Sorry William, but that's just pedantic semantics ...

Apart from which, I haven't owned a car in god knows how many years, that hasn't specified a synthetic product for its lubrication.

Arfa

"A lot" suggests a high percentage -- perhaps 25%. I doubt 25% of all motor oil sold is synthetic. Or even 20%.

You said "specified". You mean that synthetic oil was supplied with the vehicle, and was the preferred lubrication?

What kind of motor oil are you using, Earl? [''Motor oil is motor oil!''] cuhulin