Re: DC Resonance Charging Advice Sought

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

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

Hi Dave,

Your low resistance Kenyan choke is perfect for this application. The 
addition of the RC filter using a 1000 ohm resistor will reduce your 
charging supply efficiency a bit (~2.5%), your output voltage by about 600 
volts, and your bang size by about 8% (0.14) joules. You shouldn't have any 
problems with an operating frequency of 160 kHz, and you should see only a 
slight performance difference in operation. Please keep us posted on your 
progress.

Best regards,

-- Bert --
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Tesla list wrote:

>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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