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Registered Member #1497
Joined: Thu May 22 2008, 05:24AM
Location: Toronto, Ontario, Canada
Posts: 801
Linseed oil polymerizes with oxygen exposure, heating would only speed that up. Linseed oil can also spontaneously polymerize and seems like a fire risk. Try silicone oil, lower flammability risk and much higher usable temperature, it won't polymerize or oxidize like vegetable/seed oils. Certain DOT brake fluids are silicone oil and might work.
Registered Member #2628
Joined: Fri Jan 15 2010, 12:23AM
Location:
Posts: 627
Proud Mary wrote ...
Approaches to this problem range from leaving a free space above the oil inside the case filled with non-reactive non-flammable gas, having a vent which will open at a given pressure, or by using compressible materials or objects inside the casing.
If you don't take care of the pressure problem in a sealed unit in one way or another, the very least problem will be leakage.
hmm, I typically use fiberglass cases for transformers (1/8 of an inch thick or so?) and I also epoxy all the openings of the transformer, by openings I mean any screw terminals, insulators, etc... are sealed with epoxy, (in conjuntion with gasket sealant) and I put epoxy on the transformer's lid itself before sealing it up.. in my case, the housing has a lip that was designed to work in wet conditions, as well as inbuilt "clamps" that hold the lid in place, so it does not open up.
point being, I have put a transformer using mineral oil inside a completly sealed case, and have yet to run into any problems, and hopefully never will.
In my future designs, I will include some kind of a bleed valve on top of the casing.
however, the only thing Im really worried about is in the future that transformer will voilently fail and explode like a hand grenade.
time to go to sleep here, now Ill have a much easier time sleeping at night knowing I have a time bomb in my room
I wonder if it will be wise to wear a face shield, and perhaps a ton of other safty gear, and drill a 1/16 hole into the casing, and try to relieve the pressure (if there is even any).. then leaving that hole there, and putting a plug into it, and once every, say whenever I use this transformer, just unplug corky, wait a few seconds and put it back in.
Registered Member #1497
Joined: Thu May 22 2008, 05:24AM
Location: Toronto, Ontario, Canada
Posts: 801
gatedbreakdown wrote ...
Proud Mary wrote ...
Approaches to this problem range from leaving a free space above the oil inside the case filled with non-reactive non-flammable gas, having a vent which will open at a given pressure, or by using compressible materials or objects inside the casing.
If you don't take care of the pressure problem in a sealed unit in one way or another, the very least problem will be leakage.
hmm, I typically use fiberglass cases for transformers (1/8 of an inch thick or so?) and I also epoxy all the openings of the transformer, by openings I mean any screw terminals, insulators, etc... are sealed with epoxy, (in conjuntion with gasket sealant) and I put epoxy on the transformer's lid itself before sealing it up.. in my case, the housing has a lip that was designed to work in wet conditions, as well as inbuilt "clamps" that hold the lid in place, so it does not open up.
point being, I have put a transformer using mineral oil inside a completly sealed case, and have yet to run into any problems, and hopefully never will.
In my future designs, I will include some kind of a bleed valve on top of the casing.
however, the only thing Im really worried about is in the future that transformer will voilently fail and explode like a hand grenade.
time to go to sleep here, now Ill have a much easier time sleeping at night knowing I have a time bomb in my room
I wonder if it will be wise to wear a face shield, and perhaps a ton of other safty gear, and drill a 1/16 hole into the casing, and try to relieve the pressure (if there is even any).. then leaving that hole there, and putting a plug into it, and once every, say whenever I use this transformer, just unplug corky, wait a few seconds and put it back in.
You could always build in a vent with a valve, and connect a tube full of drying agent to prevent the ingress of moisture. Open valve during usage, close after finished and the unit is cool. You could also add in a simple rubber stopper held in by friction, hoping that it will act as a defacto safety valve. The oil may affect the rubber unfortunately, so no sure bets.
Registered Member #2463
Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546
however, the only thing Im really worried about is in the future that transformer will voilently fail and explode like a hand grenade.
Whether or not it will act thusly depends on the amount of energy it could draw from the source ( I^2/T) The primary resistance would limit that in a small box.
The really big oil immersed units can and do explode. (history in Europe shows why oil filled units were not used for years while in the USA they were. An early oil breaker did blow up setting a goodly part of a city on fire. The King simply banned them.)
What prevents expensive large units from catastrophic failure is extremely accurate, and routinely calibrated protective relaying. Another thing is a gadget that pops up a little beacon, if a transient burst of gas caused by an underoil arc happens releasing a bit of gas which raises the pressure in the expansion space. This telltale signal is foolproof and lets the operators know that resetting the trip, (which they do, because things unrelated to transformer can knock the thing off line) is a decision that needs a chain of authority. (arcovers often blow free).
Another thing sadly is in cases where a case violent ruptured, it was caused by the unsafe or erronious actions of operators who often do not survive their injuries.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
wrote ...
The really big oil imersed units can and do explode. (history in Europe shows why oil filled units were not used for years while in the USA they were. An early oil breaker did blow up setting a goodly part of a city on fire. The King simply banned them.)
I know. That's my job, designing condition monitoring equipment for them. If you can predict the explosion months in advance, you can make a nice bit of money. Not sure who the King of Europe is.
wrote ...
Another thing is a gadget that pops up a little beacon, if a transient burst of gas caused by an underoil arc happens releasing a bit of gas which raises the pressure in the expansion space.
That's a Buchholz relay, and these days it doesn't just pop up a beacon, it makes a relay contact that trips the whole thing out.
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Baby oil as transformer oil replacement?
