RE: DC Resonance Charging Advice Sought

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

Original poster: "Dave Kyle by way of Terry Fritz <teslalist-at-qwest-dot-net>" <dave-at-kyleusa-dot-com>

Hi Bert,

Will the RC filter have any significant impact on the coil performance? I
have the components on hand (933pf -at- 30KV and a 1K 100 watt resistor) that
should have a cutoff frequency of 170 kHz. Note my predicted resonant
frequency is 160 kHz. Any problems there?

The transformer is rated at 770 VA which I think must be very conservative
based on its enormous bulk of 50 pounds. Power could potentially rise to
1200 VA if driven by a Variac to 140 VAC but I will probably be somewhat
circumspect at least initially and keep it closer to specification.

The inductor is a real interesting one and hopefully is suitable for this
application. It is a Kenyon S-9881 20Hy 300ma DCR=125 ohms, 15KV test. It
weighs about 40 pounds!

Yes, your numbers are right in line with my calculations. If I drive the
transformer with a Variac to 140 VAC, max current should average 160 ma with
max power occuring at 500 bps. Predicted current stays well below the
inductor's 300 ma mark which is also good since the diodes are only rated to
330 ma.

Dave

=========================================
Dave Kyle
Austin, TX USA
Email: dave-at-kyleusa-dot-com


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Wednesday, August 13, 2003 6:02 PM
To: tesla-at-pupman-dot-com
Subject: Re: DC Resonance Charging Advice Sought

Original poster: "Bert Hickman by way of Terry Fritz <teslalist-at-qwest-dot-net>"
<bert.hickman-at-aquila-dot-net>

Hi Dave,

The cutoff frequency of the RC filter is really not very critical since its
purpose is to absorb transients in the high MHz region - a filter with a
cutoff frequency in the range of say 50 - 200 kHz should be quite adequate.
The high DC voltage rating of the inductor is excellent.

BTW, does the reactor's faceplate state the max DC operating current and DC
resistance? These are nice to know in order to insure that you don't
saturate the reactor, and to predict expected output voltage in operation.
Assuming your reactor does not saturate, peak reactor current will be about
~190-200 mA and average current ~120-130 mA depending upon reactor winding
resistance. The max breakrate (assuming Rreactor < 7 kOhms) is a shade
above 500 BPS. Vout and charging efficiency will be a function of your
reactor's DC resistance as follows:

Rreactor        Vout            Efficiency
(Ohms)          (Volts)         (%)
500             12397           99%
1000            12620           97.5%
2000            12009           95%
5000            10341           87.6%
10000           8025            75%

Good luck and best regards,

-- Bert --
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