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Re: [TCML] Newbe's First Coil
Greg,here is another view of the salt water cap,,interesting.
http://myweb.cableone.net/grcarhunter/bottle.htm
Joe in Texas,,,,,,Get well DC,,,we still need you.
On Sat, 06 Feb 2010 18:29 -0800, "G Hunter" <dogbrain_39560@xxxxxxxxx>
wrote:
> If you want a cheap, sturdy capacitor--right now, no waiting--consider
> the humble saltwater cap:
>
> http://myweb.cableone.net/grcarhunter/bottom.htm
> http://myweb.cableone.net/grcarhunter/swc.htm
> http://myweb.cableone.net/grcarhunter/bottle.htm
>
> For 10kv@23ma, you need something in the range of 5-7nF. 12oz beer
> bottles work well, and they're good for about 0.8nF each. If you tack on
> another OBIT in parallel, just double up on the cap size.
>
> Good Luck,
>
> Greg
>
>
> --- On Sat, 2/6/10, cbroring@xxxxxxx <cbroring@xxxxxxx> wrote:
>
> > From: cbroring@xxxxxxx <cbroring@xxxxxxx>
> > Subject: Re: [TCML] Newbe's First Coil
> > To: tesla@xxxxxxxxxx
> > Date: Saturday, February 6, 2010, 2:31 PM
> > I want to thank everybody who
> > commented on my new Tesla coil. Your input was very
> > helpful. I thought I may give an update.
> >
> > Since the initial test I rebuilt the top load buy
> > wrapping the cookie tin with 4 inch diameter aluminum duct
> > forming a 18 inch wide toroid. I then taped on a small
> > nail to encourage the sparks to start. This really
> > didn't much change the length of the streamers but they were
> > noticeably brighter.
> >
> > I added a dedicated 8 foot ground rod for the RF side of
> > the circuit. No real change in performance.
> >
> > Then I built a 4 segment spark gap out of copper pipe
> > fittings. This worked noticeably better but got hot
> > and the gap spacing closed up. So I rebuilt it and
> > added a muffin fan. This worked a lot better, had a
> > real snappy sound and significantly longer streamer from the
> > top load... for about 10 seconds. Then the fun
> > stopped! I guess the new spark gap overstressed the ceramic
> > capacitors and one of them quietly broke down.
> >
> > So now I'm in the market for a new capacitor. From
> > what I read a MMC is the way to go, but I'm kind cheap and
> > it would probability cost as much as I have in the whole
> > coil so far. Also, even after lots of reading
> > up, I'm a bit confused about choosing an appropriate
> > value both in capacity and breakdown voltage. Do I
> > need more then one string in parallel to handle the
> > current? I purchased another OBIT on Ebay so I will
> > have 2 parallel identical 10kv 23mA transformers powering
> > it.
> >
> > I haven't completely ruled out making my own
> > capacitor. The party cup design looks intriguing.
> >
> > Is there a down side to going big with the capacitor value
> > with the thought in mind that I may drive the coil with a
> > some somewhat bigger power supply in the near future.
> > I have a number of 6-7 kv radio transmitter plate
> > transformers around here that I may wish to try, so if
> > I'm buying expensive new parts, I may want to give myself
> > some room to grow. My thought is that if the capacitor
> > value is a bit larger then optimum I may have trouble
> > charging it fully with the limited OBIT power supply, but is
> > this a big liability in performance?
> >
> > Again, any suggestions are very much appreciated.
> >
> > Charlie
> > K3YA
> >
> >
> >
> >
> > -----Original Message-----
> > From: cbroring@xxxxxxx
> > To: tesla@xxxxxxxxxx
> > Sent: Sun, Jan 31, 2010 1:21 pm
> > Subject: [TCML] Newbe's First Coil
> >
> >
> > Hello to the members of this list. For no
> > particular reason I built a Tesla Coil this winter.
> > Just got it running, more or less. So (hopefully) here
> > are a couple of photo's of what I put together.
> >
> > http://img651.imageshack.us/img651/5567/1000420.jpg ;
> > http://img683.imageshack.us/img683/5931/1000424e.jpg ;
> > http://img651.imageshack.us/img651/5043/1000425.jpg ;
> > http://img651.imageshack.us/img651/5164/1000427.jpg ;
> >
> > The transformer is a 10kv 23mA oil burner trans.
> > Primary is about 12 turns # 14 sold house wire 10" diameter
> > with a couple extra taps available. Secondary is 1300
> > turns #27 on 3.5 inch pvc. Spark gap is 2 nails spaced
> > about 5/16" Capacitor is two 6000pF
> > 30kv hokey puck ceramics, and one shows a slight temperature
> > rise with use. Top load is a cookie tin and bent pizza
> > pan. The ground is the house wiring tied in to an
> > extensive ham radio/ lightening ground system.
> >
> > It really doesn't work that great. I removed a coupe
> > turns and moved the tap around to get the best coupling I
> > could. I get a ring of 2 inch sparks of the pizza
> > plate. I put a screwdriver on top and get 3-4 inch
> > sparks off that. I haven't tried bringing a grounded
> > probe to the top load yet. Anyway, I read that the
> > ceramic capacitors are not really durable and one of mine
> > shows some heating after a minuet or so of on time to. I
> > think I need to work on that next. I expected a little
> > more out of it even with the 250 watt power transformer.
> >
> > I need to figure out how to ground the thing. I need
> > a better capacitor. I have lots of big transformers and DC
> > power supplies to play with once I get the coil working a
> > bit better.
> >
> > Any suggestions are much appreciated.
> >
> > Charlie
> > _______________________________________________
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> > Tesla@xxxxxxxxxx
> > http://www.pupman.com/mailman/listinfo/tesla ;
> >
> > _______________________________________________
> > Tesla mailing list
> > Tesla@xxxxxxxxxx
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> >
>
>
>
>
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