Re: OLTC primary loss measurement

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Ted,

It is a little hard in that you should really measure the change in
temperature over time.  Such as how long it takes to raise the temperature
10C.  There is a lot of noise there but a little filtered and isolated LM35
IC based circuit could do that.  Another problem is that there is not a lot
of heat there.  About 22 watts in the IGBT array.  The caps actually have
higher dissipation.  I think the primary coil is very low indeed.  I can
just "ring down" the bare primary and find the resistance from the time it
takes the wave to get to 10% as John Couture's book explains.  I will do
this...

However, I have another giant loss problem on my hands in the secondary
that dwarfs primary losses...

Cheers,

	Terry

At 01:26 AM 8/31/2002 +1200, you wrote:
>Greetings Terry et al
>
>I wonder if it's practical to actually measure the IGBT lossses directly
>1) Operate coil in still air environment
>2) Run near full power until in thermal equilibrium
>3) Do the sums for the heatsink thermal d(temperature) from its published
>thermal resistance to air.
>4) Thus directly derive power driving the thermal rise.
>5) Compare with power I/P and volia
>Best
>Ted L in NZ
>