Thread-topic: **External Email** Re: [TCML] "Modern" Spark Gap Designs?
On that note, I found my 1 HP phasing-locking modified AC motor had barely enough torque to operate properly. Simply removing the .150 to .200" of exposed threads from the 8 aluminum barrels (used to hold the tungsten rotating contacts) was enough to reduce windage sufficiently to improve performance.
Terry
-----Original Message-----
From: Tesla <tesla-bounces@xxxxxxxxxx> On Behalf Of Tedd Dillard
Sent: Thursday, January 30, 2020 12:31 PM
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: **External Email** Re: [TCML] "Modern" Spark Gap Designs?
Don't know much about TCs but have some experience with many different types of rotating equipment. I have read a lot about rotating spark gaps and guys using one horsepower and up motors. It seems to me that starting time would be determined by the mass of the rotor but the power to run at full speed would only be limited by windage. The windage would be the only load. It would seem to me that one half horsepower would be plenty.
Are their other factors?
Teddy
On Jan 30, 2020 12:09 AM, "Steve White" <steve.white1@xxxxxxxxx> wrote:
> I think you will run into a problem if you try to bridge more than two
> gaps. I built my SRSG to allow for either 2 gaps or 4 gaps. I
> initially tried it with 4 gaps and no matter how closely I spaced the
> electrodes, I got inconsistent firing. This is with a 14.4 KV pole
> transformer. I then switched to 2 gaps and got completely consistent
> firing at 240 BPS. I have used 2 gaps ever since. My SRSG runs very
> nicely with a 1/2 HP AC induction motor modified to be synchronous.
> This is with a 12 inch diameter G10 rotor
> 1/2 inch thick running at 3600 RPM.
>
> Steve White
> Cedar Rapids, Iowa
>
> ----- Original Message -----
> From: "Dan Kunkel" <dankunkel@xxxxxxxxx>
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Sent: Wednesday, January 29, 2020 6:25:19 PM
> Subject: Re: [TCML] "Modern" Spark Gap Designs?
>
> Tedd,
> A single static gap would not quench very well, at least without the
> aide of moving air, vacuum, magnets, etc. However, a MULTIPLE series
> gap does seem to perform quite well. Yes you loose a little power with
> each "hop", but in the end you gain due to faster quenching. Each
> break allows the power to be divided up and is easier to quench.
>
> A rotary gap is OK at quenching, but it only has two "hops" (as
> compared with a typical TCBOR or RQ style gap). Plus the speed of
> electricity is much faster than the mechanical dwell time of the
> electrodes in a rotary gap. So the rotational aspect of a rotary does
> not do anything for quenching. Plenty of folks have reported
> "following around" on a rotary gap due to lack of quenching (there are videos on youtube as well).
>
> ~Dan
> Kansas city area
>
> On Wed, Jan 29, 2020 at 5:32 PM Tedd Dillard <tedd.dillard@xxxxxxxxx>
> wrote:
>
> > Why would a static gap quince better than a rotatary gap?
> >
> > On Jan 29, 2020 5:14 PM, "Gary Lau" <glau1024@xxxxxxxxx> wrote:
> >
> > > I have no experience with gaps for anything larger than an NST
> > > power
> > supply
> > > so can't comment on the series quench configuration. But based on
> > > my experience, I suspect the use of PVC in proximity to the gaps
> > > is a less than ideal idea. Even using a single NST, the white PVC
> > > turns an unsightly brown color due to the intense UV emitted by
> > > the gap. I
> don't
> > > know how its insulating or mechanical strength might be affected,
> > > but better to use G10 if available.
> > >
> > > Regards, Gary Lau
> > > MA, USA
> > >
> > > On Wed, Jan 29, 2020 at 1:03 PM Daniel Kunkel
> > > <dankunkel@xxxxxxxxx>
> > wrote:
> > >
> > > > Hello Tesla List!
> > > > I am starting to work on my next spark gap for a 6-10 KVA magnifier.
> It
> > > > seems the definitive spark gap design is that from Richard
> > > > Hull/TCBOR
> > > using
> > > > a rotary gap (to control timing only) combined with a multiple
> > > > break
> > > series
> > > > gap (to control quench only). Is there a better approach for gap
> design
> > > and
> > > > construction?
> > > >
> > > > Currently my plan is to use a 3.5 HP DC motor to spin a G10 disk
> > > > with tungsten electrodes and combine it with the PVC + copper
> > > > tubes + fan
> > > series
> > > > gap.
> > > >
> > > > Thanks,
> > > > ~Dan
> > > > Kansas City area
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