Gentlemen,
let a newbie expose his ignorance.
I don't now much about these things and most of what I think I understand
is from Richie Burnett page.
If I understand what he says about spark gap is that the whole idea is to
charge the capacitor as much as possible while the gap is conducing.
If there is no difference between how the spark gap effects streamer length
then it seems that there is no difference in the capacitor charge.
this suggest to me that the capacitor is smaller than it could be and is
fully charging no matter the gap dwell time.
In his discussion on TC design Richie starts out with determining the best
resonant frequency for a given break rate and determines the ballast and
capacitor values to get the best power through put and power factor..
It is then that he talks about optimizing the phase relationship of the
mains to the firing rate.
Am I completely out to lunch?
Teddy
On Tue, Jul 10, 2018 at 4:47 PM, Terry Oxandale <toxandale@xxxxxxxxxxxxx>
wrote:
> 2X on Steve's observation. This is the primary reason my SRSG now sits on
> a shelf after all the milling, capacitor, and inductor construction
> investment to obtain what I felt would have been a technically superior
> set-up. Instead, I found that the difference was indiscernible, and that
> the simpler ARSG was the final winner overall. With that said, I use a
> variable speed DC motor, and there is a narrow range of rotor speed that
> produces the best breakouts.
> Terry
>
> From: Steve White <steve.white1@xxxxxxxxx>
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Sent: Tuesday, July 10, 2018 1:57 PM
> Subject: Re: [TCML] SRSG 200bps or 100bps choice
>
> When I built my pole pig powered coil I also built a SRSG designed for 240
> BPS at 60 Hz. I also built one of the electronic variable phase controllers
> based on a large variac and capacitors which you can read about elsewhere.
> The phase controller allows the phase to be varied electrically from 0 to
> almost 90 degrees confirmed through testing. My motor has 2 flats ground on
> the armature for synchronous operation. Using my oscilloscope and an LED
> sensor, I carefully aligned the SRSG to fire at phase angles of 0, 90, 180,
> and 225 degrees without the use of the electronic phase controller. My
> intention was to then use the variable phase controller to experiment with
> different firing phase angles off of nominal.
>
> I then operated the coil without the phase controller and noted the spark
> length and characteristic. I then used the phase controller to adjust the
> phase angle. To my surprise, the phase angle made no discernible difference
> in the spark length or characteristic. I tried offsets of 0 to almost 90
> degrees. My only conclusion is that the phase angle makes little difference
> at 240 BPS at 60 Hz at least at the 4.8 KVA power level that I am currently
> using. This makes me think that the easier-to-build ARSG might be a better
> choice at the 240 BPS rate for high power coils.
>
> Steve
>
> ----- Original Message -----
> From: "phil" <pip@xxxxxxxxxxx>
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Sent: Tuesday, July 10, 2018 3:57:10 AM
> Subject: Re: [TCML] SRSG 200bps or 100bps choice
>
>
> Do you why that would be the case? Ive never built a rotary gap coil and
> would like to know more :)
>
> Thanks!
>
> Matt
>
> On Sun, Jul 8, 2018, 4:22 PM <pip@xxxxxxxxxxx> wrote
>
> Do you why that would be the case? Ive never built a rotary gap coil and
> would like to know more :)
>
> Thanks!
>
> Matt
>
> ------------------------------------------------------------------
>
> Matt.
> My observations were based on just that - observations. We, that is
> myself and another UK coiler, have ran both SRSG and ARSG coils, as well
> as statics and each tends to display different streamer characteristics,
> although it's mainly the rotary coils where this is noticeable.
> A very good explanation on RSG and static gaps and the pros and cons is
> at Richie Burnett's excellent web site, as my own brain cells have lost
> their edge lately on the more technical aspects.
>
> Richie's site is at www.richieburnett.co.uk/ and there is info on my
> own site http://www.hvtesla.com. Also try the archives on here.
> Basically once you've decided on either a static or rotary (RSG) gap,
> then if you choose rotary you then have two flavours: SRSG or ARSG. The
> latter Asynchronous rotary is quick and easy to build, while a
> Synchronous rotary is more efficient at lower bps rates, but also a lot
> more work to achieve, needing motor modification and careful control of
> the phase using some form of phase control, and also care is needed with
> the MMC size**. Probably only worth it if you want to squeeze every last
> bit of performance out of a coil.
> An SRSG at 100/120 bps (50 or 60Hz) can be particularly challenging as
> you can then run into some very high resonant voltages if you get the
> phase wrong. This is now thought to behind the damage at my other recent
> posting:
>
> https://www.pupman.com/listarchives/2018/Jul/msg00019.php entitled "Bad
> strike to a 12 inch traditional coil (somewhat
> terminal)"<https://www.pupman.com/listarchives/2018/Jul/msg00019.php>
>
> To sum up:
> Static: - Easy to build, generally suited up to 6 or 7kW (yes I know
> others have ran twice that)
>
> Rotary ARSG:- Easy to build, handles power better than a static with
> theoretically no upper level for hobby coiling.
>
> Rotary SRSG:- Lot more work involved, most efficient up to 300bps
> (particularly at 200/240 bps) if pursuing 100% power, harder to run,
> handles power as ARSG above.
>
> People often try SRSG but don't get success because MMC size and phase
> are critical. (See "resonant charging" on Richie's site)
>
> I've left out 'triggered gaps' another thing that used to interest me,
> but never got around to trying.
>
> Good luck experimenting.
>
> ** Note: MMC resonance is affected by both mains frequency AND the bps
> rate if using synchronous. Richie calls it resonant charging and has an
> old TCML post reproduced here with the graphs he refers to (now dead
> links):
>
> http://www.hvtesla.com/richie.html
>
>
> Phil
>
>
> On 09/07/18 15:27, Matthew Sweeney wrote:
> > Do you why that would be the case? Ive never built a rotary gap coil and
> > would like to know more :)
> >
> > Thanks!
> >
> > Matt
> >
> > On Sun, Jul 8, 2018, 4:22 PM <pip@xxxxxxxxxxx> wrote:
> >
> >> If you have wondered on how each perform, especially in their streamer
> >> behaviour, have a look here:
> >>
> >> https://youtu.be/Sm8SoFmnlLM
> >>
> >> There is a general feeling that 200bps will give marginally longer
> >> strikes, while 100bps is better for ground strikes.
> >>
> >> Phil T
> >> _______________________________________________
> >> Tesla mailing list
> >> Tesla@xxxxxxxxxxxxxxxxxx
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> >>
> > _______________________________________________
> > Tesla mailing list
> > Tesla@xxxxxxxxxxxxxxxxxx
> > https://www.pupman.com/mailman/listinfo/tesla
>
> --
> Regards Phil www.hvtesla.com
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>
>
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