> Has anyone tried extending the power capability by placing one in oil? Im
> aware of the flux density, core size and all that but just curious how
> much
> leeway there is.
>
> Right now Im contemplating 500W of AB2 out of a 300W CCS modulation xfmr.
> It
> is not potted and the end bells are removable.
>
> Only a scope will tell me when Ive exceeded the saturation limit.
I've not tried it with small transformers but it should work. How much would
be gained is another matter.
Normal transformers should run into I^2R loss problems well before they even
approach saturation limits unless they have poorly designed cores. However a
DC component through the transformer could cause it to saturate.
Saturable Core Reactors (SCRs) and Magnetic Amplifiers both use the
saturation of the core by a DC current to control the output, but the number
of turns in the control windings is large compared to the regular windings.
BTW they work very well with a clean output compared to Silicon Controlled
Rectifiers (SCRs). They just tend to be big, HEAVY, and expensive and they
don't interact.
Depending on the thermal qualities of the oil, (Mineral Oil or Silicone 200
fluid) and proper mounting of the transformer and how well the oil can get
to the windings, taking a SWAG I'd expect to see any where from around a 30%
to 100% gain in power handeling capabilities. 200 fluid of the proper
viscosity has the better thermal conductivity, (and less fire hazard) but it
may be hard to find and expensive. The viscosity ranges from a couple of CS
(think alcohol or dry fly treatment) to well past 6000 (think a can of STP)
I'd think anything of a couple hundred CS or less should work but I should
caution it's been over 11 years since I had anything to do with this stuff
so my "remembered" numbers may be off a bit.
>
Even removing the shells I'd expect the typical paper covering on the
windings to limit the thermal transfer and as a result the power handeling
capacity increase to less than 50%. Just mount the transformer in the
container of oil, stick a temperature sensor on the transformer, hook up a
resistive load that will draw the desired current at the proper voltage, and
*slowly* ramp up the voltage using a variac while measuring the temperature
compared to that of the transformer ratings.
This makes me wonder how a properly designed, sealed container filled with
200 fluid and with CPU coolers mounted to the surface of said container
would work. The heat pipes (using vpaor phase cooling) are amazing in their
ability to remove heat. So a transformer in a sealed container of cooled oil
should be very effective. of course that leads to the extreme of pumping
refrigerated coolant through the transformer container.
Good Luck,
Roger (K8RI)
> How about a power xfmr?
>
> Carl
> KM1H
>
>
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