Re: [TCML] Effects of SRSG Dwell Time on Coil Performance

[Gary Lau <glau1024@xxxxxxxxx>]

I have only ever used a 3600RPM motor in both a propeller and small
disk-based SRSG, but I haven't had any balance issues.  Granted the disk was
relatively small (6" x .09" thk).

If the gap is to be synchronous, then using a belt drive is a bad idea,
unless it is a cog belt that won't slip, but that's just adding an
additional layer of complexity and offers no advantage as far as balance,
economy, or simplicity.

Regards, Gary Lau
MA, USA

On Mon, Sep 27, 2010 at 7:28 AM, Teslalabor <teslalabor@xxxxxxxxxxx> wrote:

> Hi John,
> thank you for that explanation. I think I will have to try this. Just
> replace the 3000rpm motor by 1500rpm, adding another 2 rotating electrodes
> and see what happens. If there is no re-firing, the main advantage of
> 1500rpm I can see is, that the mechanical balancing of the rotating disk or
> the propeller in propellerdesign-gaps, is much easier done. BTW, another
> idea is to use a 1500rpm motor in combination with a gearmeachanism or
> simply a belt drive with a gear ratio 1:2 to achive 3000rpm. Think this
> might work well.
>
> Stefan
>
> ----- Original Message ----- From: "Futuret" <futuret@xxxxxxx>
> To: <tesla@xxxxxxxxxx>
> Sent: Sunday, September 26, 2010 5:46 PM
> Subject: Re: [TCML] Effects of SRSG Dwell Time on Coil Performance
>
>
> Stefan,
>
> That's a good question.  A faster mechanical dwell time is generally
> better.
> There's an old myth that fast dwell time gives faster gap quenching.  In
> reality
> the quench-time depends more on output spark streamer loading.  But if the
> mechanical dwell time is too long, a condition called "re-firing" of the
> spark gap can occur, which results in very inefficient operation.  This
> re-firing occurs when the capacitor is able to recharge to a sufficient
> voltage to permit the cap to fire again while the electrodes are still
> aligned
> from the previous firing.  Many factors determine whether a gap will
> re-fire such as; low rotary rpm, small rotary disc diameter, small
> capacitor size,
> wide electrode diameter, narrow electrode gap spacing, etc.  Usually
> re-firing is
> not a problem until the factors mentioned reach an extreme, or combine
> to the extreme.
>
> Generally speaking, the faster 3000 rpm is preferable to the 1500 rpm.
> That said, you'll usually see no difference in performance either way.
> The 300 rpm might give a little more of a swirling air effect, and slightly
> help the quenching that way.  Fast quenching is preferable, if it can
> be achieved without increasing gap resistive losses.
>
> Cheers,
> John
>
>
>
>
>
> -----Original Message-----
> From: Teslalabor <teslalabor@xxxxxxxxxxx>
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Sent: Sun, Sep 26, 2010 9:50 am
> Subject: [TCML] Effects of SRSG Dwell Time on Coil Performance
>
>
> Hi List,
> I allready have built some nice SRSG's with very good results. All of my
> SRSG's run with 200BPS. They use 2 rotating and 4 stationary electrodes.
> They run with 3000rpm Motors (50Hz here in Germany).
> I also own many 1500rpm sync.motors. So the question is:
>
> Let's say, there is some TC system with given parameters. It runs with
> 200BPS.
> Can somebody tell me, which effects in performance result in the different
> dwell times, when using a 3000rpm Motor with 2 rotating and 4 stationary
> electrodes OR use a 1500rpm Motor with 4 rotating and 4 stationary
> electrodes?
> In both cases there are 200BPS but the dwell time is different!
>
> Greets
> Stefan
>
>
>
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