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Re: [TCML] SRSG 200bps or 100bps choice



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
>> https://www.pupman.com/mailman/listinfo/tesla
>>
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxxxxxx
> https://www.pupman.com/mailman/listinfo/tesla

-- 
Regards Phil www.hvtesla.com
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