[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [TCML] 5.25" SRSG tesla coil suggestions on improving performance
Scott and all,
ASRSG was the key! I found a DC motor that fits perfectly in my sync motor's cradle, so it was a direct swap. Fed it with a bench adjustable power supply, and here are the results with a rough tune.
http://www.youtube.com/watch?v=Y2zR48p2hmA
And that's a rough tune, with my cap still missing 3 strings! Streamers are around 48" now, MUCH hotter, and more stable. I'll get another video tonight when its not as bright out in the garage.
Yea, I'm still using the acrylic disc. I am working on locating some tufnol or similar so I can build a better disc. I also have a pair of 1/4" tungsten electrodes on the way to replace the stationarys so they don't heat up as fast.
Thanks again for all the suggestions! I'll keep you updated as it continues to evolve.
-JJ
________________________________
From: Scott Bogard <sdbogard@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Wednesday, August 7, 2013 5:23 AM
Subject: Re: [TCML] 5.25" SRSG tesla coil suggestions on improving performance
JJ,
Please do switch to ASYNC, I absolutely guarantee performance will
improve, as you can use a smaller normal sized cap, and use a high break
rate to transfer all the energy you want. I've been using two MOTs
unballasted for a while, it is a good system, but for low break rates I
suspect all your energy is wasted as losses. You'll still trip a breaker
occasionally if you don't use a ballast, but that energy will go to spark
growth instead of a spark gap space heater... See my coil here,
http://www.youtube.com/watch?v=_301ZMR6H48
Scott Bogard.
On Tue, Aug 6, 2013 at 11:10 PM, JJ Dasher <redrum0381@xxxxxxxxx> wrote:
> Hi,
> So this evening I removed the PFC, and the performance did not change
> much. Maybe slightly worse. The phase did shift, and I had to re-adjust
> my motor.
> As for the tank cap, Teslamap actually suggests 470nf for 4.4kv @ 300ma,
> or 236nf @ 150ma for SRSG.
> Regardless, I shrank my MMC this evening from 188nf, to 131nf by removing
> a few strings. Performance was significantly worse after retuning the
> primary to about 3-3.5 turns.
>
> Maybe I just need to switch to async since building a cap that size would
> be ridiculously expensive...
>
> What do you guys think about switching to async??
>
> Thanks for the info!
> -JJ
>
>
> ________________________________
> From: Scott Bogard <sdbogard@xxxxxxxxx>
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Sent: Tuesday, August 6, 2013 9:58 AM
> Subject: Re: [TCML] 5.25" SRSG tesla coil suggestions on improving
> performance
>
>
> JJ,
> MOTs do not need ballasting when you use only 2. With that said if
> you use a doubler that will likely no longer be true, I can't watch your
> video as I am at work but I'll do that when I get home to see what is going
> on. Gut instincts having mastered the two MOT system, ditch the PFC, they
> are NOT helping you if you are only getting 36 inches of spark, they are
> hurting, your current draw should be low at that spark length. Second,
> your BPS is to low being synchronous for that cap size. I use a 80nF and
> 700-900 BPS and get close to 60 inches of spark (spark continually
> increases with BPS until that range) your capacitor is 2.25 times bigger
> than mine, so your BPS should be 2.25 times slower than mine, so in the
> 350-450 BPS range, which is not really possible with a SYNC gap. You could
> quadruple your electrodes and get 480 BPS, which is close, but you might
> have unexpected problems doing 480 BPS sync. My advise for a better fix is
> to get a properly sized tank cap if you insists on going sync, it is
> definitely the easiest fix, a quick and dirty calc suggests 460 nF, but
> that seems high, so I'd use Java TC and see what is the recommended SYNC
> gap cap size assuming 4kV and whatever wattage is reasonable (around 1.5 kW
> is reasonable, so a secondary current of 375 mA for your calcs). You may
> wish to assume less current since MOTs have a little bit of current
> limiting, 250 is generally what we see in the field...
>
> Scott Bogard.
>
>
> On Tue, Aug 6, 2013 at 9:59 AM, w5als <w5als@xxxxxxxxx> wrote:
>
> > Hi
> > First I am no expert at this, with that said looking at your
> > pictures the tuning does not look to be right at 2.25 turns
> > and I would think that MOT's would have to be ballasted to keep the
> > current down. I have never use mot's before
> > and may be totally wrong here. I hope some one else put there input in on
> > this. I did not crunch the number on
> > this for the tuning neither, I may be wrong but I think that may be a
> > problem to.
> > alton
> >
> >
> > On 8/5/2013 8:59 PM, JJ Dasher wrote:
> >
> >> Hi all,
> >> I'm new here. Although I've built a few coils in my past, I still
> >> consider myself a newb coiler. I've never been the type to do things
> >> mathematically perfect, and tend to wing it as I go along, which may be
> my
> >> downfall here. For the past couple of years on and off, I've been
> working
> >> on a 5.25" SRSG coil to use in a Halloween display. This is my largest
> >> coil so far. You can see it in action here:
> >>
> >> http://www.youtube.com/watch?**v=2P3T5zuT9DI<
> http://www.youtube.com/watch?v=2P3T5zuT9DI>
> >>
> >>
> >> and pictures of the guts here:
> >>
> >> http://imgur.com/a/0jgxR
> >>
> >>
> >>
> >> I'd like to get some constructive criticism and advice on getting this
> >> running better. This trips my 20amp breaker after about 10-15 seconds
> of
> >> running, so I figure about 2.2-2.6kw? I'm currently getting 36"
> streamers,
> >> which I feel are somewhat weak. They are purple, and not very bright.
> >> Specs:
> >>
> >> Large old powerstat variac salvaged from power equipment. Not sure on
> >> exact specs, but I assume it should handle 30+amps with ease. Wired for
> >> approx 150v boost.
> >>
> >> Dual MOT's (pulled from 1200w commercial MWs), currently unballasted.
> >> 130uf of PFC caps behind them.
> >> 180nf MMC cap built with 10 strings of 8x 942c20p15k-f's. 1m bleed
> >> resistors installed.
> >> SRSG is a 5" acrylic disc attached to a 1800rpm sync motor. 4 flying
> >> electrodes for 120bps. Electrodes are 1/8" thoriated tungsten. Phase
> is
> >> adjusted by twisting the motor in its mounts.
> >> Primary is 3/8 copper tubing, slightly conical. Currently tuned at
> about
> >> 2.25" turns
> >> Secondary is 5.25" x 24" 22awg magnet wire with a couple of coats of
> poly.
> >> Topload is a spun aluminum 4.5"x18" toroid.
> >> All high current busses are 4awg stranded copper with large soldered
> lugs.
> >>
> >> The next improvement I plan is to upgrade to 1/4" tungsten electrodes.
> >> The stationary electrodes currently glow red hot after about 5 seconds
> of
> >> running, so I added a fan.
> >> I'd love to get some bright long white snakes like I've seen from
> similar
> >> size coils. Please advise!
> >>
> >> Thanks!
> >> JJ
> >>
> >> P.S. There is normally a safety gap installed, It just wasn't in place
> >> when I took those pictures.
> >> ______________________________**_________________
> >> Tesla mailing list
> >> Tesla@xxxxxxxxxx
> >> http://www.pupman.com/mailman/**listinfo/tesla<
> http://www.pupman.com/mailman/listinfo/tesla>
> >>
> >
> > ______________________________**_________________
> > Tesla mailing list
> > Tesla@xxxxxxxxxx
> > http://www.pupman.com/mailman/**listinfo/tesla<
> http://www.pupman.com/mailman/listinfo/tesla>
> >
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
>
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla