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Registered Member #3414
Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245
Patrick wrote ...
Ash the pipe has been changed to steel pipe with 1.4" ID, I will use 1/2 " acrylic, or maybe i can snag some poly-carb, but Carl Pugh suggests some plastics are unstable at vacuum.
I think 15 PSI across 1.4 dia. is like 1.53in^2 so its seeing 23lbs of force, not that much, of course SA increrases as a square, so force can build quickly on larger windows.
I would fabricate this as a 3 or 4 inch diameter plastic circle on a pipe flange so only 1.4" dia is actually unsupported at vacuum.
That sounds OK to me, even overkill maybe.
I may have some spare glass windows around that size (1.4"), You don't get the outgassing issues with glass. I'll have a look.
Registered Member #3429
Joined: Sun Nov 21 2010, 02:04AM
Location: Minnesota, USA
Posts: 288
Patrick wrote ...
I do have a supplier for "Shell Diala AX", $100 USD for 1 GAL, $155 USD for 5 GAL, plus shipping.
I wouldnt mind buying new oil off Ebay, but a whole 55 GAL barrel local pick-up only in Ohio, thats sure as shit not going to happen.
I also have 32 assorted HV resistors on the way from my best supplier, r_francis82, for this project.
$100 for ONE GALLON? THAT'S ROBBERY! If I knew that I could consistently sell oil at $100 per gallon, I'd quit working on X-ray heads and go into business selling oil! And what's up with that deal about getting FIVE gallons for only $55 more? That doesn't sound logical at all. And does that price include shipping cost, or is shipping extra?
Edit: OOPS, I just noticed the "plus shipping". That makes it even a worse crime!!!
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
Xray wrote ...
Patrick wrote ...
I do have a supplier for "Shell Diala AX", $100 USD for 1 GAL, $155 USD for 5 GAL, plus shipping.
I wouldnt mind buying new oil off Ebay, but a whole 55 GAL barrel local pick-up only in Ohio, thats sure as shit not going to happen.
I also have 32 assorted HV resistors on the way from my best supplier, r_francis82, for this project.
$100 for ONE GALLON? THAT'S ROBBERY! If I knew that I could consistently sell oil at $100 per gallon, I'd quit working on X-ray heads and go into business selling oil! And what's up with that deal about getting FIVE gallons for only $55 more? That doesn't sound logical at all. And does that price include shipping cost, or is shipping extra?
Edit: OOPS, I just noticed the "plus shipping". That makes it even a worse crime!!!
Robbery! Yeah it is! Are you willing sell it to me for less? Well thats the best I can find, I have been considering using candle wax, I can get 12 pounds for $8.
Registered Member #1064
Joined: Tue Oct 16 2007, 05:04PM
Location:
Posts: 42
The book, Transformer Engineering by Blume et al has graphs for transformer oil dielectric strength, effect of air pressure effect of dissolved air effect of frequency effect of shape of electrodes effect of temperature effect of time of voltage application The curve for effect of dissolved air indicates a strength of 42 KV RMS at start, 30 KV RMS after 5 minutes, 48.7 KV RMS after 30 minutes and 43.5 KV RMS after 180 minutes
In 1999 I purchased 5 gallons of Diala AX oil for $4.31/gallon from Golden Gate Petroleum in Hayward CA. Today is Saturday and they don’t answer their phone, but you can try Monday (510) 783-6500.
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
Carl Pugh wrote ...
The book, Transformer Engineering by Blume et al has graphs for transformer oil dielectric strength, effect of air pressure effect of dissolved air effect of frequency effect of shape of electrodes effect of temperature effect of time of voltage application The curve for effect of dissolved air indicates a strength of 42 KV RMS at start, 30 KV RMS after 5 minutes, 48.7 KV RMS after 30 minutes and 43.5 KV RMS after 180 minutes
In 1999 I purchased 5 gallons of Diala AX oil for $4.31/gallon from Golden Gate Petroleum in Hayward CA. Today is Saturday and they don’t answer their phone, but you can try Monday (510) 783-6500.
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100 micron Vacuum drying dielectric oil...
THAT'S ROBBERY! If I knew that I could consistently sell oil at $100 per gallon, I'd quit working on X-ray heads and go into business selling oil! And what's up with that deal about getting FIVE gallons for only $55 more? That doesn't sound logical at all. And does that price include shipping cost, or is shipping extra?