Re: Concerning Peter's DC Drive

From: 	Peter Electric[SMTP:elekessy-at-macquarie.matra-dot-com.au]
Reply To: 	elekessy-at-macquarie.matra-dot-com.au
Sent: 	Saturday, July 19, 1997 2:00 AM
To: 	Tesla List
Subject: 	Re: Concerning Peter's DC Drive

Tesla List wrote:
> From:   Larry Robertson[SMTP:LWRobertson-at-msn-dot-com]
> Sent:   Wednesday, July 16, 1997 8:22 PM
> To:     Tesla Builders
> Subject:        Concerning Peter's DC Drive
> Hi Folks
> I also have been thinking for a while that a DC drive would
> be not only more efficient, but would also make the rotary gap
> completely uncritical as to speed, up to maximum power delivery.
> As I was contemplating on how to get the small resonance cap.
> recharged, I thought that we use a pulse discharge already,
> so why not pulse charge it as well. If the large cap is big
> enough compared to the small cap., having them in series from
> the point of view of the primary coil should not change the
> resonant frequency much. For instance, if the small cap is
> 0.02 uf and the storage cap is 1 uf, when viewed in series
> the capacitance is 0.0196, not much of a difference.
> The diagram below might actually be legible if viewed with
> a monospaced font, such as "QuickType Mono" which I used to
> make it.
> Think about a rotary gap consisting of two poles rotating,
> and four poles stationary. Two adjacent stationary poles are
> connected together, and go to the resonance cap. The other
> side of the resonance cap goes to one side of the primary
> coil, the other side of the primary goes to a common which
> I'll call ground. The two remaining stationary poles go to
> the HV end of the storage cap, and to ground, respectively.
> As the gap rotates, the resonance cap will be alternately
> charged from the storage cap, and shorted to ground. The
> primary coil will alternately see the small cap and large
> cap in series with it, then just the small cap in series,
> but with opposite polarity.
>                                    Rotary
>                                       ------
>                                       v     |  Small
>      + ------ RFC---------o-------->     <--o-  CAP ----
> >From                      |           ^                 |
> Diode                   Large         |              Primary
> Bridge                   CAP          |                Coil
>                           |           |                 |
>      - -------RFC---------o-----------o-----------------
> I think a diode bridge would make most efficient use of the
> transformer.


I like your idea of the 4 stationary pole rotary gap better than my
commutator idea as it would be much easier to build and probably doesn't
need a lathe to construct.

I'm a bit confused about the effect of having the two caps in series
with the primary though. It would seem to me that you would
alternatively get .01 then .1 across your primary coil giving you two
separate resonance frequencies. In practice it probably wouldn't matter
as you would be tuning the coil to the .01 cap and any other resonance
you get would die down very rapidly.

I suppose the "proof of the pudding is in the eating" so to speak, so
let us know how it works if you get to try it. By the way I am intending
to use two microwave trannies wired anti-phase with the voltage doublers
and diodes that come with the Microwave ovens. This will give me approx
8-10Kv DC. Apparently this idea has worked well for Roger Smith's DC
coil, which I am told is a real performer!


Peter E