| SINGLEENDED |
Oil caps? Very good for tubes amp/ preamps.
What about this.
1. 1:1 fully isolated power supply for the whole tube setup.
2. 110v / 240v input to 110v / 240v output @ 30Amps.
3. Fully submerge in transmission oil.
4. How isit giong to sound
5.:(
6.:D |
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| bear |
Ur confused.
Oil in a cap is part of the dielectric material.
It has a measureable effect as a dielectric.
It has a scientific and engineering basis.
The result is that oil caps have a 'sound'.
Oil in a transformer "bath" is not part of the inductive circuit.
It performs two functions:
- prevents dielectric BREAKDOWN (high voltage breakdown) better than air
- permits better COOLING of the transformer
It should have little or no effect on the "sound",
_-_-bear
PS. I have no idea what the idea of your numbered things is at all...
I think ur talking about a high KVA isolation transformer?? If so that has some merits if set up properly. |
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| zigzagflux |
Most significant application of fluid-filled transformers is regarding environment and maintenance.
Oil xfmr can fit same kVA in smaller core/coil package.
Can provide lower maintenance, as it doesn't require cleaning.
Can provide longer life, as the insulation stays drier and cooler (relatively).
Typically has higher BIL ratings due to enhanced dielectric of oil.
Can be used outdoors, due to sealing from environment.
I see no advantages in performance with regards to audio.
If you plan on using an oil xfmr indoors, I am 99% sure UL would require both a biodegradable and low flash point fluid. This rules out just about everything except vegetable oil.
I would say you're wasting your time. |
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| salas |
| Some truly ultra fi guy maybe will find beneficial sound signature due to nice oil dampening of self resonances and the like. Just maybe. All parts have a sound when things are getting under scrutiny. Please don't start an oil immersion rage in the Far East. I can easily imagine a $90.000 Kondo in an oil filled fish tank! |
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| Beelzebub |
Reasons for oil-filled Tx:
1. Improved cooling (Oil conducts heat better than air)
2. Protects Tx from environment (especially in the tropics)
3. Possible acoustic damping?
4. Snob-value - looks neat?
Oil is not a better electrical insulator than air, and there are problems with adequately sealing the unit whilst allowing external connections. |
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| SINGLEENDED |
1. It's run cool that for sure.
2. Easy maintenance, as it is housed in a metal casing .
3. It provide better damping from all other electrical equipments.
4. It's very much quieter than the other trans that I have.
5. As for sonic difference . You need one to know the answer.
6. I am running a 5 A unit for my Preamps and I notice the quietness it does to the supply.
7. Over in Asia our local supply is Very2 dirty all sort of noise will creep into the audio passage.
8. My next project 240v 3 phase Out 240V @ 30A 3 Phase
9. Thanks for some of the answer.:) :smash: |
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| poynton |
Have you made this ??
Let's see some photos !!
Andy |
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| bear |
Oil is a much better insulator than air.
From Radiotron:
dielectric strength
Air - 19.8-22.8 v/mil
Paraffin Oil 381 v/mil
Modern oils used for electrical and electronic applications are better.
What air does better is the dielectric constant.
_-_-bear
---edit: ah nevermind - I misread a post... ha! |
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| Brian Beck |
A small caution: A lot of high-quality vintage transformers, chokes and HV caps used polychlorinated biphenyl (PCB) oils. These compounds are extremely toxic. If you run across one of these devices and are tempted, please be careful. There is some comfort if there are no leaks after all these decades, but a miswiring could result in an overheated transformer and PCBs spewed across your living room. Newer HV devices made with something other than PCBs might say "No PCBS" or "PCB free". PCBs had several trade names that you can find at the bottom of this US EPA page:
PCB trade names
I have a similar fear of mercury vapor rectifiers. Drop one of those in your house and you've suddenly created a hazardous zone. |
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| Beelzebub |
| quote: | Originally posted by bear
Oil is a much better insulator than air.
From Radiotron:
dielectric strength
Air - 19.8-22.8 v/mil
Paraffin Oil 381 v/mil
Modern oils used for electrical and electronic applications are better.
What air does better is the dielectric constant.
_-_-bear
---edit: ah nevermind - I misread a post... ha! |
I stand corrected bear! I found it difficult to get exact figures, but it does look like various oils have at least 3x the dielectric strength of air. You learn something new each day :) |
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| SINGLEENDED |
| quote: | Originally posted by Beelzebub
I stand corrected bear! I found it difficult to get exact figures, but it does look like various oils have at least 3x the dielectric strength of air. You learn something new each day :) |
Now I am wandering why not leave it ON all the time as it sound better after 5hrs when it is warm . Thanks bear for the info.
poynton the pix will have to wait ,as i have to remove the unit and take it apart .I am still experimenting with different type of oil , till i find the type suited for me. As for now i am getting quite oily.:D |
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| salas |
| Told you, that $90.000 Kondo is gonna dip in that oil filled fish tank soon, somewhere in Hong Kong or Tokyo. :smash: |
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| radtech |
| How deep does it need to be? Will I need to put my boots on? |
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| SINGLEENDED |
| quote: | Originally posted by radtech
How deep does it need to be? Will I need to put my boots on? |
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| SINGLEENDED |
| quote: | Originally posted by SINGLEENDED
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Get a used weilding transformer casing .
It is good for housing up to 10A coil. depending on your country voltage.I post a few shot of a second unit I am refurbishing later.
:idea: |
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| bear |
For DIY transformer oil, get Mineral Oil from your druggist.
It is not bad as transformer oil, and it is NON TOXIC!!
All other commercial transformer oils are both not soluable in almost anything known to man, and are not good for you. Older PCB laden oils should be avoided at all costs.
New, modern transformer oils are ok to use, but contact with skin should still be avoided. That means plastic gloves, etc.
Use the Mineral Oil, be safe.
Motor oils are generally not suitable, as they burn at too low of a temperature, and have no fire retardant properties.
_-_-bear |
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| SY |
Mineral oil has the advantages of low cost and easy availability. But for thermal stability and long term reliability, silicone is much superior. Dow-Corning 561 is one I'm very familiar with and is a great choice if you've got a distributor who will sell small quantities.
Likewise, Fluorinert has superb dielectric and thermal properties but costs $$$.
More info:
http://www.dowcorning.com/content/p...uid/default.asp |
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| zigzagflux |
For cheap and easy to find, consider castor oil. Safe, good dielectric, likes water. Available in small quantities. Biodegradable.
I would, personally, avoid silicone fluid, nothwithstanding it is relatively expensive. Silicone was chosen for transformers due to its low flash point. However, it is not nearly as good a dielectric as mineral oil, RTemp, FR3 (Cooper Power). Worst of all, it doesn't like water. This means moisture will prefer the paper insulation instead of the fluid. That's bad. There are VERY few transformers manufactured today that use silicone.
Cooper has great results with vegeatable oil (FR3), but it is specially processed so it doesn't oxidize and rot. Good luck getting small quantities (I have 50 gallons at work, though :)
Highly recommend castor oil or mineral oil. If it were up to me, not having access to FR3, I would go castor oil. |
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| burnedfingers |
| Lets use a good grade of Vegetable oil and submerge the core. Lets also leave the top open and this way it has a dual purpose of providing cooling for the transformer and a means of cooking our French Fries. |
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| SY |
| quote: | | Worst of all, it doesn't like water. |
Actually, that's "best of all." You do not want the material to be hygroscopic; a bit of water really screws the dielectric properties. It's also a prime component in thermal breakdown (hydrolyzes hydrocarbon oil). FWIW, it's what I use at work for our high voltage plasma and microwave-fired UV lamp power systems; we've had zero problems with it. |
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| SINGLEENDED |
That the oil I"m using now. Its been more than a week now, and there is no bad news yet. Still running cool and its on 24hrs.It is getting better every day. Just ripoff a second unit casing , got into some problems , the auto X forner is too big for the casing that i want to house it. Special coil is required to house in this weilding casing. Need to order a new A/X former with input 1phase output 3phase. Or go back to my first design.
Thanks to all U guys out there for all the informations. Very glad for all the helps rendered.:) :D and all the:angel: :smash: :smash: |
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| poynton |
Just a thought - As with other audio components, do oil baths have to 'Burn-in'?
Andy |
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| SINGLEENDED |
| quote: | Originally posted by poynton
Just a thought - As with other audio components, do oil baths have to 'Burn-in'?
Andy |
No but the copper wire that is use to make the coil needs to burn -in . Just like most amps. |
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| zigzagflux |
Practically speaking, using a transformer at less than 1000V will not matter much for dielectric issues, but I would like to clarify a few things:
| quote: | Originally posted by SY
You do not want the material to be hygroscopic; a bit of water really screws the dielectric properties. It's also a prime component in thermal breakdown (hydrolyzes hydrocarbon oil). |
This is a common misconception, which the industry has moved away from. The very desirable properties about new fluids are improved flash point, biodegradability, and improved water absorption. Attached are some cute graphs of the water saturation characteristics of traditional mineral oil and FR3.
What this really says is that given the choice between the two fluids, FR3 can solute more water without its dielectric properties changing. With a fluid that doesn't like water, a little bit will affect its dielectric properties (as you said). However, I can absorb 20 times as much water in FR3 before affecting my dielectric breakdown comparable to mineral oil. Utilities are migrating to FR3 primarily for the environmental benefits, but the superior water absorption characteristic is an additional bonus.
An article, http://www.just4sheep.com/site/images/FR3.pdf by Cooper Power is attached, which addresses the bigger problem of water in the paper. A little bit of water in the paper insulation is more detrimental to the cellulose chains than a small degradation in the fluid's dielectric properties. Polymerization of the paper results in free radicals, acid, sludge, and weakened mechanical strength. Wet paper is subject to partial discharge, where wet fluid is not. For long life, the paper should be dry.
We sample and test oil-filled transformers every week, ranging from 15 kVA to 7500 kVA, up to 69 kV. Dielectric strength and moisture content are among the tests performed on the fluid. Dielectric strength is actually low on the food chain for quality criteria. It's all over the place. One sample could be 50 kV (ASTM D1816) while the next is 20 kV. They are both in good condition, as the design of a transformer is not critically dependent on the insulating qualities of the fluid- the design allows for a lot of variation. More important is moisture content, interfacial tension, acidity, and dissolved gas.
| quote: | Originally posted by poynton
Just a thought - As with other audio components, do oil baths have to 'Burn-in'? |
All transformers go through a stage of mechanical expansion/contraction. The windings seat themselves, and the core blocking wears in (sometimes gets loose). So I would say there is definitely a "break-in" period, more so than a "burn-in" period. Does this affect performance? I would think very little.
To bring us back to reality, given the voltages involved, most of this thread is overkill, and you could probably throw in some Orville Redenbacker's popcorn oil and be just fine. In addition, you are talking about a dry type transformer being filled with fluid. The dielectric properties of a dry type are dependent strictly on solid insulation and geometry. The addition of oil will only improve things, but would not affect performance. It will affect life. |
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| poynton |
| quote: | Originally posted by poynton
Just a thought - As with other audio components, do oil baths have to 'Burn-in'?
Andy |
Oil - 'Burn-in' :) |
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| ak_47_boy |
| next stop, cryogenically treated oil :( |
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| zigzagflux |
| Forgot the attachment |
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| SY |
| zigzag, remember that the goal here is not high dielectric breakdown, but low dielectric constant consistent with mechanical damping. We're thinking of different things when I used the rather imprecise term "dielectric properties." Sorry for the confusion. |
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