RE: A new mini-coil competition winner!

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Lau, Gary" <Gary.Lau@xxxxxx>

I hooked my mini coil, very similar to Karl's, to an analog Wattmeter.
I have the same NST, gap, and cap.  At 120VAC in, it draws between
160-190 Watts.  My digital scope shows between 120-150 BPS.

Regards, Gary Lau
MA, USA

> Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>
>
> Hi Karl,
>
>
> >Original poster: "Karl L." <karl@xxxxxxxxxxxxxxxxx>
> >
> >Thanks John.  I have a kill a watt meter, and during initial testing
> >of the primary I found a variac'd firing range of ~150 - 185 VA.  No
> >caps or coils were connected, only the xfrmr and gap.  Curiously,
> >the PF was 0.26 and it indicated a draw of around 40 watts.  The
> >kill a watt doesn't work when the coil is actually firing (too much
> >RF hash on line.) - Karl
>
> Plug the Kill a watt meter directly into your outlet and run an
> extension cord to the coil located further away.  This worked for me
> for a 1KW coil. I'm not sure if you are using a separate RF ground
> but if not you may want to try that (outside) to help keep the RF off
> of the mains.  Also, dont coil your extension cord as this allows a
> larger pickup of RF on the power cord. Lastly, if you still have
> problems, you may want to use a line filter.  My 1KW coil didn't have
> a filter and things worked OK.
>
>
> >>I wouldn't be surprised if Karl's coil is firing 3 or even 4 times
> >>per 60Hz half cycle.  A resonant value cap can cause the
> >>cap to charge very quickly.
>
> Yes, with a 5KV gap and resonant charging, you should be getting
> around 190 BPS.  Measure the "real" power at the wall and estimate
> the BPS using:
>
> BPS = POWER(wall) / BANG(energy)
>
> This will be an upper limit on BPS since there is some losses in the
> transformer.  Some of those losses can be measured if you want to by
> measuring the primary and secondary resistance, Rp and Rs.  You can
> measure the primary current  with  your killawatt meter and estimate
> the secondary current using the turns ratio.  The primary resistance
> may be too low to measure directly so put say a 1 amp DC current
> source thru the primary and measure the Vdc in mv across the
> primary.  This reading will translate directly to resistance in milli
> ohms.  Now you can calculate the copper losses in the transformer
> primary and secondary using the I^2R method and subtract these
> calculations from the wall power.  This will get you closer to the
> power processed at the SG but still not perfect since we have not
> accounted for the core losses.
>
> It will be interesting to see how close this comes to the 190 BPS
> prediction based on simulations.
>
> Gerry R.
>
>