Spurious Precision Alert!! was Re: Suggestion on Power Supply?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>


>Note that a say 15000Vrms transformer has a peak output voltage of 15000 x 
>SQRT(2) = 21213.2 volts.  You multiply the RMS voltage by 1.4142... to get 
>peak volts.

I would say that a 15kVrms transformer has a peak output voltage of 
21kV.  I doubt that the nominal RMS output voltage of the transformer is 
15000.0 volts +/- 0.1 V (although, I will grant that you might have 
accumulated some sort of nifty precision HV transformer...), and, of course 
that assumes your line voltage is whatever the nominal nameplate line 
voltage is (120V? 117V? 115V?)

Just as a general rant, TCs are fairly non-precision devices, so it's 
probably not worth carrying precision of better than 1-5%.  You had better 
have enough adjustability in the system to accomodate that kind of variation.

Naturally, one can and should make measurements to a higher precision if 
investigating small scale effects on a like to like basis (like evaluating 
resonant frequency and losses in a secondary with changes in weather), but 
for initial design purposes, 5% is probably sufficient.


Curmudgeonly yours,
Jim