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Re: final prep of coil
Subject: Re: final prep of coil
Date: Sun, 8 Jun 1997 10:34:49 -0600
From: "DR.RESONANCE" <DR.RESONANCE-at-next-wave-dot-net>
To: "Tesla List" <tesla-at-pupman-dot-com>
To: Chuck Curran
We ran some of your data thru our computer program. Looks like an
excellent coil design but you need a lot more upper terminal capacitance
for optimum output with this monster. Suggest at least 3 terminals of
the
size you are using -- triple the capacitance on top. At least double as
a
minumum.
Happy sparking.
DR.RESONANCE-at-next-wave-dot-net
----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-poodle.pupman-dot-com
> Subject: Re: final prep of coil
> Date: Saturday,June 07,1997 9:21 PM
>
> Subject: Re: final prep of coil
> Date: Sat, 07 Jun 1997 20:34:16 -0500
> From: Chuck Curran <ccurran-at-execpc-dot-com>
> To: Tesla List <tesla-at-pupman-dot-com>
> References: 1
>
>
> Tesla List wrote:
> >
> > Subject: final prep of coil
> > Date: Sat, 07 Jun 1997 12:57:40 -0400
> > From: Michael Bauer <mbauer-at-execpc-dot-com>
> > To: tesla-at-pupman-dot-com
> >
> > That last couple weeks I have made much progess on my latest coil. I
> > have
> > done rough tuning but need to finish my grounding system and disconnect
> > a
> > few ham radio antennas. My yard is really limited in size here in
town,
> > so
> > only low power settings will be used until I transport it up to my
> > "cabin up
> > north". Part of the fun in this project was building a good power
> > control
> > cabinet. I loaded a full height 19" rack cabinet with a TEK scope,
> > control
> > relays and time delay relays, electronic sampling of voltage and
current
> > nodes, SCR DC motor control for the RSG, variac panel with cooling fan,
> > etc.
> > In the tuning tests I found out the I get resonance just at the end of
> > my
> > primary coil. I may need to add another turn or two of tubing if I
> > change
> > to a larger toroid. Here are my coil specs, and if anyone has
questions,
> > feel free to ask.
> >
> > primary coil: 6 3/4 turns of 1/2" copper tubing, spaced 1.375", with
22
> > " ID.
> >
> > Primary cap: (two) 0.2 uf/20 kvdc caps in series for 0.1 uf/40 kvdc (I
> > may
> > need to upgrade voltage rating here)
> >
> > RSG: 3600 RPM DC motor, 3/4 Hp, belt drive to spindle mounted 12" disk
> > with
> > 12 studs on 10" circle. Studs are 5/6" brass, fixed electrodes are
3/8"
> > stainless. DC motor SCR speed controller is 0 - 90 vdc with reversing
> > relays and start/stop input. Speed is controlled by a pot for any
speed
> > between 0 and 3600 RPM.
> >
> > Secondary coil: 20" OD by 40" tall, wound on wooden form. Three
plywood
> > disks support 1/2" X 1" slats open spaced around perimeter. Slats are
> > glued
> > and doweled to disks. About a third of the wire is supported by
slats,
> > the
> > rest of the perimeter is air spaced. 17 turns per inch, or about 675
> > turns.
> > Final tune with toroid is 66 Khz.
> >
> > Toroid: 6" by 30" aluminum ducting covered in aluminum tape. Center is
> > tape
> > covered plywood. Ends of duct were first hot melt glued together
before
> > taping.
> >
> > Transformer: 10 Kva pole pig, 2 insulating electrodes on secondary.
> > 14.4
> > Kv/25.3 Kv depending on internal HV connections. I made a safety gap
> > assembly that mounts to the output studs that allow easy setup for
Jacob
> > ladder demo's.
> >
> > Ballast: 140 amp welder with manual taps for low volt current side.
> >
> > variac: 240 vac/16 amp. Not nearly big enough but I am fan cooling it
> > with
> > a large squirrel cage fan until it blows or I find a cheap replacement.
> >
> > Conrol panel: Low voltge relays, start/stop buttons, and indicators
for
> > power up sequencing. I added time delay lockouts between powering the
> > RSG
> > and pig power to give the motor time to spinup (10 sec). Main
contactor
> > is
> > 100 amp rated.
> >
> > Instrument panel: Volt and current measurements of many points
> > simultaneously, each sensing circuit feeding a BNC connector. Current
> > sensing done with hall effect current loops feeding op amp circuitry.
> > Variac voltage and current displayed on panel meters.
>
> Michael:
>
> You sure have made a lot of progress since your last update. I'd really
> like to see your coil before you haul it up north--any chance? I am
> interested in how the wooden secondary form is going to work out. I
> believe that others have used Stitka Spruce, (probably spelled that
> wrong) for forms but I am not aware of exactly how they are sealed, if
> at all. Keep us posted. You also mentioned your op amp metering
> circuit--Um, I blew up two digital meters in about 2 minutes last year,
> so just a forwarning, hope you excel at shielding that circuit. I would
> suggest adding about two more primary turns for tuning activities, hope
> your structure will allow for that. Have fun!
>
> Chuck Curran