Hi Carl,
> Has anyone tried extending the power capability by placing one in oil?
I have not yet, but might try it soon, with some 10kW power
transformers. I'm just trying to learn enough about dissipation in oil
to find out how much copper and steel I would save by using oil as
cooling medium. I will wind these transformers myself. While designing
them, based on non-oil construction, I found that to keep them at a safe
temperature, I need a huge amount of iron and copper, which drives up
the cost. If anyone on the list has a good source of information on
oil-immersed design, I would welcome the hint!
> Im aware of the flux density, core size and all that but just curious
how much leeway there is.
Basically if you take a given transformer designed for air use, and put
it in oil, you should be able to run it at significantly higher current
(and thus power), but not at much higher voltage (because of iron
saturation), and you would have to accept the higher copper loss (seen
as voltage drop).
> Right now Im contemplating 500W of AB2 out of a 300W CCS modulation
xfmr. It is not potted and the end bells are removable.
That should be an easy case, as long as you don't run it at higher
voltage or lower frequency than it is designed for.
> Only a scope will tell me when Ive exceeded the saturation limit.
That will happen if you put too much voltage at too low a frequency into
it. If the oil impregnates it well enough to increase the insulation,
you might run it at higher voltage AND limit the lowe frequency end at
the same time, if that's acceptable. This would still keep it out of
saturation, and the higher iron loss will be dissipated by the oil, so
it will be no problem.
> How about a power xfmr?
In these you cannot usually choose anything about operating frequency,
but otherwise it's the same.
By the way, if anyone wants a copy of my transformer design spreadsheat
(in Excel format), either to validate it with your own designs or to
actually be so brave and use it, it's available for free!
Manfred
XQ2FOD
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http://ludens.cl
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