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Re: Research Project (fwd)
Original poster: List moderator <mod1@xxxxxxxxxx>
---------- Forwarded message ----------
Date: Wed, 23 May 2007 17:21:46 -0600
From: Gary Peterson <g.peterson@xxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Research Project
Drake wrote:
> My 12kv/90ma coil is nearing completion and I was thinking that I could do
> some sort of experiment with wireless power transmission. . . . I recall
> someone talking about rigging up another coil to attach to a lightbulb
> which could be lit up from a fairly significant distance. I've researched
> this a bit but I can't really find anything about a receiving coil and
> light bulbs, so if anyone has info it would be greatly appreciated.
The photo at www.teslaradio.com/images/000_0298-1.jpg shows a Tesla
receiving transformer with widely-adjustable variable elevated terminal.
The terminal is not very robust, but it does give a very wide range of
tuning and this is particularly useful when first configuring a
transmitter-receiver pair. See www.teslaradio.com/pages/sstc-a.htm for an
index of additional photos such as
http://www.teslaradio.com/images/000_0339-1.jpg and other information.
For the load, it is best to use a very small incandescent lamp connected to
the receiving transformer's secondary winding. I like to use a single low
voltage clear Xmas tree light because they are cheap and plentiful, and
perform well. An LED will also perform quite well and will light up at more
than twice the distance because of the lower current drain on the receiver.
Here are the specifications of this particular Tesla receiver.
Primary
Coil form: Single layer of craft paper w/ 3/32" acrylic ends, coated
with polyurethane finish
Form diameter: 11"
Form length: 18"
Primary wire size: AWG #22
Turns: 630 (approx.)
Winding length: 17.5"
Inductance: 57.5 mH
Resistance: 28.5 ohms
Height of bottom turn above ground: 16.5" + 6" (pallet height) = 22.5"
Secondary
Wire size: AWG #18 cord
Secondary turns: 18 (ends left open, i.e., diminutive lamp load
disconnected when E-field probe detector is used)
Winding length: 1.68", first turn starts 0.875" above lowest primary
turn
Elevated terminal
Aluminum foil rolled on to a 7/8" wooden dowel
Width: 18"
Length: adjustable from 1.5" to 60"
Maximum height above top turn:
Ground terminal
Fire hydrant or any other low-resistance grounding point
Connecting wire: 57.5' AWG #14 cord
It is important to keep in mind that your 12kv/90ma SGTC is a damped-wave
oscillator in contrast to an undamped or "continuous wave" oscillator. I
did improvise a damped-wave Tesla coil RF transmitter back when I was on the
International Tesla Society Board of Directors, ca. 1990. It was based upon
a fellow board member's tabletop TC display unit. I modified its
glass-plate capacitor by adding another sheet of aluminum foil. The approx.
1" knob topload was replaced with a copper flush-valve assembly float, and
moved off of the secondary on to an improvised insulated stand a few inches
higher than its original position and a little bit off to the side. The
receiving transformer, prepared beforehand, had an AWG 30 gauge primary
wound on a 1.75" cardboard tube. The secondary was wound on top of this
towards the lower end of the single-layer coil in exactly the same fashion
as Tesla did when he was in C/S in 1899. The load, by my recollection,
consisted of a single 6-volt pilot light. The elevated terminal was a sheet
of aluminum foil hung off of another improvised stand made of wooden sticks.
The lamp was brightly lit at a range of about 15 feet. It's not at all hard
to do.
Drake wrote:
> . . . after looking at some audio modulated tesla coils with their "plasma
> speakers" I would love to build one. The only problem is that I really
> have a limited knowledge of electronics outside of SGTC's and SSTCs seem
> like a whole different animal. . . .
One big difference is that SGTCs are damped or partially damped oscillators
depending upon the break rate. The faster the break rate the closer one
comes to achieving continuous wave operation. One big advantage to the SSTC
(and the VTTC as well) is that the break rate is easily brought up to the
secondary's resonant frequency thus allowing CW operation, which is
preferable if one is interested in wireless energy transmission. Another
advantage of the SSTC is the ease of primary circuit tuning. One doesn't
have to fiddle around making adjustments to the primary capacitor and a
primary tap. The exact same result is achieved by a simple adjustment of
the pulse generator's frequency.
Drake wrote:
> . . . at the moment it looks like I will probably be doing some sort of
> experiment with wireless power transmission. I have a question regarding
> that though. All of these programs out there are designed for maximum
> spark length, but what about maximum RF output?
Greater spark length is acheived by reducing the break rate resulting in a
longer interval between discharges of the primary capacitor. This is the
case for the typical SGTC and also the DRSSTC.
For wireless transmission simply increase the break rate up to the vibration
rate of the resonator. It is also important to charge the primary capacitor
with direct current. The objective is simply to acheive the greatest
potential on the elevated terminal with the greatest possible break rate
with no sparks issuing.
> . . . I know usually one would put a large toroid on top, but is there
> anything else? Should I change the tap on the primary coil or what?
Once you have the transmitter built and in place with a robust ground
connection and an elevated terminal, simply adjust the primary capacitor and
the primary tap so that the primary vibration is the same as the secondary
vibration. The objective is to develop the maximum e-field around in the
vicinity of the transmitter. Use a cheap analog volt meter set on a lower
AC volts scale with the COM terminal lead to ground and a long V terminal
lead supported up in the air as an e-field probe. A fluorescent tube on a
grounded stand also works fairly well. Also, the transmitter does not have
to be powered up to the point where the thing is almost sizzling and sparks
are just about to break out. When everything is properly tuned up the
transmission and reception takes place even at very low power levels.
> . . . Someone mentioned trying to get more amperage rather than voltage
> out of the secondary. Does this mean that a TC for RF transmission is
> built differently?
The design is the exactly same with the exception that the topload should be
elevated above the helical resonator's top turn. For a constant diameter of
resonator, the length of the vertical cylindrical conductor between its top
turn up to the elevated terminal can be shortened and at the same time the
resonator itself lengthened until a point is reached at which the topload is
once again directly adjacent to the top turn.
> Someone off list sent me a link to Eastern Voltage Research's (Daniel
> McCauley) website. . . . Does anyone know anything about this company and
> their products.
I recommend McCauley's book DRSSTC BUILDING THE MODERN-DAY TESLA COIL :
ELECTRICAL AND MECHANICAL DESIGN. It's available through Lulu at
http://www.lulu.com/content/298063 .
A few additional suggestions:
1) Join the Wireless Energy Transmission Yahoo Group (
http://tech.groups.yahoo.com/group/wireless_energy_transmission/ );
2) Pursue an amateur radio operator's license, General Class or higher;
3) Familiarize yourself with the following:
1a) FCC 47 CFR Part-5 Rules: Experimental Radio Service (other than
broadcast)
http://www.access.gpo.gov/nara/cfr/waisidx_02/47cfr5_02.html .
1b) OET Experimental Licensing System (Under Part-5 Rules)
https://gullfoss2.fcc.gov/prod/oet/cf/els/index.cfm .
1c) Application For New or Modified Experimental Radio Station Authorization
(Form 442)
https://gullfoss2.fcc.gov/prod/oet/cf/els/forms/442Entry.cfm
2a) FCC 47 CFR Part-18 Rules: Industrial, Scientific, and Medical Equipment
http://www.fcc.gov/Bureaus/Engineering_Technology/Documents/cfr/1998/47cfr18.pdf .
2b) Methods of Measurements of Radio Noise Emissions from Industrial,
Scientific and Medical Equipment
http://www.fcc.gov/Bureaus/Engineering_Technology/Documents/measurement/mp5/mp5-1986.pdf .
3a) FCC 47 CFR Part-15 Rules: Unlicensed RF Devices
http://www.fcc.gov/oet/info/rules/part15/part15-2-16-06.pdf .
Regards,
Gary
Gary Peterson
Phone: 970-453-9293
Fax: 970-453-6692
www.teslaradio.com
www.teslabooks.com
www.teslascience.org
> ---------- Forwarded message ----------
> Date: Mon, 21 May 2007 18:09:41 -0500
> From: Drake Schutt <drake89@xxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: Research Project (fwd)
>
> Thanks for your replies everyone, at the moment it looks like I will
> probably be doing some sort of experiment with wireless power
> transmission.
> I have a question regarding that though. All of these programs out there
> are designed for maximum spark length, but what about maximum RF output?
> I
> know usually one would put a large toroid on top, but is there anything
> else? Should I change the tap on the primary coil or what? Someone
> mentioned trying to get more amperage rather than voltage out of the
> secondary. Does this mean that a TC for RF transmission is built
> differently? Luckily I have all of my materials, but not much is built
> yet
> so it's fine if I need to make design changes.
>
> Someone off list sent me a link to eastern voltage research's (Daniel
> McCauley) website. It looks like he is coming out with a book and a kit
> for
> an audio modulated tesla coil sometime this month. I emailed him but
> haven't gotten a reply yet. Does anyone know anything about this company
> and their products. I just don't want to waste my time on plans and kits
> like some other website that shall remain nameless. I'm also still not
> sure
> if I'm even qualified to build such a thing because I wouldn't know an FET
> if
> it bit me . . !
>
> Thanks
> Drake
> ---------- Forwarded message ----------
> Date: Mon, 21 May 2007 11:01:31 -0500
> From: Drake Schutt <drake89@xxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Research Project
>
> Well summer is almost here and next year I will be a senior in high
> school!
> As seniors we are required to do an independent research project over the
> summer, putting a minimum of 40 hours into it, and following up next
> school
> year with a 15 page paper. I see this as a perfect excuse to do some
> coiling as i haven't had much time this year. This is where I have
> trouble
> deciding where to go with this.
>
> My 12kv/90ma coil is nearing completion and I was thinking that I could do
> some sort of experiment with wireless power transmission. I know it's
> inefficient, but I recall someone talking about rigging up another coil to
> attach to a lightbulb which could be lit up from a fairly significant
> distance. I've researched this a bit but I can't really find anything
> about
> a recieving coil and light bulbs, so if anyone has info it would be
> greatly
> appreciated.
>
> I also love music and after looking at some audio modulated tesla coils
> with
> their "plasma speakers" I would love to build one. The only problem is
> that
> I really have a limited knowledge of electronics outside of SGTC's and
> SSTCs
> seem like a whole different animal. I'm not dumb, I just want to know if
> it's realistic to think that I can build a SSTC that can replicate this
> plasma speaker effect over the summer. I haven't seen anything about
> these
> audio coils on the list before, but I would bet that somebody out there
> knows about them.
>
> Also, if anyone has any more ideas that involve HV and TC's that would be
> feasible to do over the summer, please reply!
>
> Thanks as always,
> Drake Schutt