[Amps] Distilled water in a dummy load ?
Joe Subich, W4TV
lists at subich.com
Sat Feb 13 14:17:32 EST 2021
> For the amount of brief testing I do, and sometimes with low duty
> cycles, sometimes high duty cycles, distilled water just might be
> easier to work with vs xfmr oil.
The issue would be time/duty cycle. Distilled water has a lower
specific heat (1 BTU/F/lb vs. ~1800 BTU/F/lb) and lower boiling
point (212 F vs ~570 F). Water would heat and boil much more
quickly than transformer oil (even if one used vapor point - ~150 F
for some oils - instead of boiling point).
... Joe, W4TV
On 2021-02-13 12:08 PM, Jim Thomson wrote:
> Is it possible to use distilled water in a hb dummy load ?
> DL consist of 4 x 200 ohm globars, wired in parallel..in an 8 gallon container.
> I welded 4 x 3 inch OD thick wall Alum pipes together, 2 stacked above 2.
> One resistor resides dead center in each alum pipe. Each resistor is a
> new globar type SP, 12 inches long x 1 inch in diameter.
> For the amount of brief testing I do, and sometimes with low duty cycles, sometimes
> high duty cycles, distilled water just might be easier to work with vs xfmr oil.
> To be used from 160-10m, no higher freqs.
> What I am worried about is the dielectric constant of distilled water. That appears
> to be a lot higher than that of xfmr oil. It could add a bunch more stray C to the mix,
> esp with each resistor inside its own alum pipe..and pipes welded.
> On paper, distilled water should be able to extract heat a lot better than xfmr oil.
> Jim VE7RF
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