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Re: First Light for 10" Coil.



Original poster: tesla <tesla-at-paradise-dot-net.nz> 

Hi Ben
I see Peter has explained the wiring of the MOT's . This is the normal
method that most use. There are some sche,es using multiple MOT's to improve
isolation but I've not experienced any problems with secondary to core
breakdown. I personally earth the core to put a barrier between the mains
and the HV side, I believe some float the core.

Thanks to Peter for description of ballst system
Rgds
Ted L in NZ
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, December 25, 2003 6:00 AM
Subject: Re: First Light for 10" Coil.


 > Original poster: Ben Haylett <bhaylett-at-shaw.ca>
 >
 > Congratulations on an impressive looking coil, Peter.
 >
 > How do you (and presumably Ted as well) have your 6 MOTs configured? In
 > other words, what sort of series/parallel arrangement are you using, and
 > what would the output voltage be?
 >
 > Ben
 >
 > ----- Original Message -----
 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > To: <tesla-at-pupman-dot-com>
 > Sent: Tuesday, December 23, 2003 10:46 PM
 > Subject: Re: First Light for 10" Coil.
 >
 >
 >  > Original poster: tesla <tesla-at-paradise-dot-net.nz>
 >  >
 >  > Greetings Peter
 >  >
 >  > A most interesting coil and quite similar to my own
 >  >
 >  > Very interested in the way you have done things
 >  >
 >  > The differences
 >  > Mine has 90nF of the 1600v 0.33uF caps (like Robin Copini)
 >  > SRSG is currently 300bps and all electrodes are near the 90deg and
270deg
 >  > points. This needs fixing, How did you decide on the location for your
 >  > rotating electrodes to set timing
 >  >
 >  > I use PFC of over 100uF and up to 6 MOT's. The MOTs I have are in oil
and
 >  > phased about ground. I use 900watt xfrmrs. I run fixed ballasting of
 > 22mHy.
 >  > I was intrigued by your ballast and would be interested in the short
form
 >  > specs on that.
 >  >
 >  > I have just purchased the bits to put a dedicated outlet at the house
so
 >  > should be able to run the thing flat out.
 >  >
 >  > My operating freq, toroids and so forth are pretty similar, I can maker
 > the
 >  > beast do 2 metre O/P but I know it will do better when I get SRSG
timing
 >  > better and a dedicated mains. It will run > than 40amps if I let it so
 > need
 >  > to keep it at that level or things start to go wrong, like fuses start
to
 >  > blow.
 >  >
 >  > Hope to hear more from your expts
 >  >
 >  > Rgds
 >  > Ted L in NZ
 >  > ----- Original Message -----
 >  > From: "Tesla list" <tesla-at-pupman-dot-com>
 >  > To: <tesla-at-pupman-dot-com>
 >  > Sent: Wednesday, December 24, 2003 8:54 AM
 >  > Subject: First Light for 10" Coil.
 >  >
 >  >
 >  >  > Original poster: "Peter Reid" <peter-at-reidconsulting-dot-com.au>
 >  >  >
 >  >  > Hello Everyone on the Tesla Coil Mailing List.
 >  >  >
 >  >  > I have just finished building my new MOT powered 10" Coil and
managed
 > to
 >  >  > tune it somewhat. I am quite happy with the results so far, however
I
 > am
 >  >  > wondering if anybody could shed some light onto areas I should work
on
 > In
 >  >  > order to improve the spark length and power handling capabilities of
 > this
 >  >  > coil. So far I have managed occasional 8.5ft Power Arcs to a
grounded
 > rod.
 >  >  > However I feel that the coil is still capable of a lot more.
Initially
 > the
 >  >  > spark output was quite poor until I increased the coupling between
the
 >  >  > primary and secondary. (I don't think I've gone too far).
 >  >  >
 >  >  > I will list the specifications below. With the current setup I am
 > getting
 >  >  > quite powerful arcs to the strike rail and ground with-in about a
3ft
 >  >  > radius around the coil.
 >  >  >
 >  >  > I have posted some photos on my website for anyone that's
interested. I
 >  >  > also have some pretty good video footage, but that isn't on the
 >  >  > webpage.
 >  >  >
<http://tesla.reidconsulting-dot-com.au/>http://tesla.reidconsulting-dot-com.au
 >  >  > Any input / help with improving the current setup would be greatly
 >  >  > appreciated, I am just a little worried about burning up my
secondary
 > if I
 >  >  > try and pump any more power though it.
 >  >  >
 >  >  >
 >  >  >
 >  >  > Coil Specs are as follows..
 >  >  >
 >  >  > Primary
 >  >  > Flat Spiral, Wound with ½ In Copper tubing, spaced but ½ inch.
 >  >  > ID = 12.7in
 >  >  > OD = 32.5in
 >  >  > Turns = 10.25, tapped at about turn 6.15
 >  >  > Primary sits 1.5ft above the ground on a specially made wooden
 > platform.
 >  >  > Strike Rail = 1/2copper tube raised by ½ inch around outside of
 > primary.
 >  >  >
 >  >  > Secondary
 >  >  > Wound on a 10" PVC pipe, which has been baked and sealed with many
 > coats
 >  > of
 >  >  > polyurethane.
 >  >  > Winding length = 41in
 >  >  > Wire Diameter = 0.9mm B&S Gauge 19
 >  >  > The bottom turn of the secondary is elevated 1 inch above the top of
 > the
 >  >  > primary winding.
 >  >  >
 >  >  > Toroid
 >  >  > 12" x 42.5" (Tube Diameter x Outside Diameter of Toroid)
 >  >  > Mounted 12in above the top winding on the secondary.
 >  >  >
 >  >  > Measured Res Frequency of Secondary is 84.8kHz, and primary has been
 > tuned
 >  >  > to exactly that. (Can someone please tell me if its worth trying to
 > detune
 >  >  > it by 1/3 of a turn to account for streamer loading etc?.)
 >  >  >
 >  >  > Capacitor
 >  >  >              0.15uF MMC Cap Bank made up of 144, 942C20P15K caps.
 >  >  >
 >  >  > Power Supply
 >  >  >              6 MOT Supply, Currently Ballasted to 40A -at- 240V (Using
a
 >  >  > Sliding Choke Balast)
 >  >  >              Maximum line draw current of 80A -at- 220v when the
ballast
 > is
 >  >  > removed. That's 17.6kVA J
 >  >  >              Approx 12kV output.
 >  >  >
 >  >  > Spark Gap.
 >  >  >              200bps Sync Gap, with a Remote Phase Adjuster.
 >  >  >              Single Gap, Tungsten static electrodes, and 4 x 8mm
brass
 >  >  > threaded rod (moving electrodes) Spinning on a 12in
 >  >  > G-10 disc (3000 rpm) Gap spacing is about 1-2mm total.
 >  >  >
 >  >  >
 >  >  > BTW, Thanks to everybody who has contributed to the mailing list,
the
 > help
 >  >  > I have received from you guys has been invaluable.
 >  >  >
 >  >  >
 >  >  > Regards
 >  >  >
 >  >  > Peter Reid.
 >  >  >
 >  >  >
 >  >  >
 >  >
 >  >
 >
 >
 >