Hello Dan,
You can find all sorts of varying sizes of these kits by searching “Tesla Coil Loudspeaker (i.e. true audio capable) Kits” in eBay...Beware, because many of the units are listed as “kits,” but they are actually preassembled and avoid the “can play square wave (MIDI) music.”
Here’s the largest preassembled “loudspeaker TC:”
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F232080863612
It looks as if the true unassembled kits for the larger sizes (compared to the mini TC’s) are no longer available...Just keep checking.
Good luck in your search, Dan!
Bill
Sent by Macak’s humble servant.
> On Jan 18, 2019, at 8:19 AM, tesla-request@xxxxxxxxxx wrote:
>
> Send Tesla mailing list submissions to
> tesla@xxxxxxxxxxxxxxxxxx
>
> To subscribe or unsubscribe via the World Wide Web, visit
> https://www.pupman.com/mailman/listinfo/tesla
> or, via email, send a message with subject or body 'help' to
> tesla-request@xxxxxxxxxxxxxxxxxx
>
> You can reach the person managing the list at
> tesla-owner@xxxxxxxxxxxxxxxxxx
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Tesla digest..."
>
>
> Today's Topics:
>
> 1. Re: NST Durability (Allen Bishop)
> 2. Re: Ebay tiny plasma speaker kits (Dan Kline)
> 3. max spark length (jimlux)
> 4. Re: TC Max Spark Length & Output Voltage (Udo Lenz)
> 5. Re: TC Max Spark Length & Output Voltage (William Fox)
> 6. Re: NST Durability (Amnite Ascended)
> 7. Re: Let's Get Small (Peter Terren)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 16 Jan 2019 19:24:00 -0700
> From: Allen Bishop <co60bishop@xxxxxxx>
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Subject: Re: [TCML] NST Durability
> Message-ID: <FECD8F05-9AD3-42AF-BCC2-D791073E675E@xxxxxxx>
> Content-Type: text/plain; charset=utf-8
>
> I have powder coated a lot of stuff and for the powdered paint to melt and fuse to the metal when the item is placed in the pre heated oven the surface temperature has to reach the melting point and remain there for a long enough period for the fusing to the metal. Because the NST is such a large mass and the tar will draw the heat away from the metal you are going t have a mess. I suggest using Eastwood?s car ceramic based undercoat paint. It?s almost as tough as powder coating without all the hassle.
>
> Allen Bishop
> Colorado Springs
>
> Sent from my iPad
>
>> On Jan 16, 2019, at 6:10 PM, Bart Anderson <gort@xxxxxxxxxxxxxxxx> wrote:
>>
>> Hi Jeremiah,
>>
>> I have de-potted a couple NST's by setting an electric stove top burner onto a large coffee can and the NST on top of the burner. Stove tops get to roughly 350-400?F and the tar does melt. When it does, the tar will ooze out of any opening such as the LV and HV bushings. But, it takes a while at that temp to get the tar melted and I don't think 20-40 minutes in the powder-coat oven is going to melt it fast enough. But, it's a risk. As someone already said, if you can put a dead NST through it first, you might save yourself an oops.
>>
>> Take care,
>> Bart
>>
>>
>>> On 1/16/2019 6:47 AM, Amnite Ascended wrote:
>>> Sorry if your first thought was, "Jesus man.... Millionth time...
>>> Fragile...."
>>>
>>> Anywho. So I want to see if a whole, working, NST will survive getting
>>> powder coated. My main concern is the windings insulation.
>>>
>>> For those unfamiliar with the process, here is a quick overview.
>>> The NST will get sandblasted. Then hung on a rack. The rack and NST will
>>> then be grounded. The powder is charged so it easily sticks to the grounded
>>> object. Then the NST will be heat treated to melt and bond the powder. This
>>> is sticking it in an oven for 20-40 minutes, at temps between 325-425 f.
>>> Lugs will of course been protected. The tar smell/smoke shouldn't be an
>>> issue.
>>>
>>> I've never unpotted one of these, so seeking the experiences of the list.
>>>
>>> Thanks,
>>> Jeremiah
>>> _______________________________________________
>>> Tesla mailing list
>>> Tesla@xxxxxxxxxxxxxxxxxx
>>> https://www.pupman.com/mailman/listinfo/tesla
>> _______________________________________________
>> Tesla mailing list
>> Tesla@xxxxxxxxxxxxxxxxxx
>> https://www.pupman.com/mailman/listinfo/tesla
>
>
>
> ------------------------------
>
> Message: 2
> Date: Thu, 17 Jan 2019 01:51:42 +0000 (UTC)
> From: Dan Kline <daniel_kline7657@xxxxxxxxx>
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Subject: Re: [TCML] Ebay tiny plasma speaker kits
> Message-ID: <307773.877411.1547689902136@xxxxxxxxxxxxxx>
> Content-Type: text/plain; charset=UTF-8
>
> William,Do you happen to have any links to the larger units?Thanks,Dan K
>
> From: William Fox <wm9fox@xxxxxxxxx>
> To: tesla@xxxxxxxxxx
> Sent: Wednesday, January 16, 2019 3:39 PM
> Subject: Re: [TCML] Ebay tiny plasma speaker kits
>
> Dear Mr. Nico,
>
> All of the eBay tiny plasma speaker TC kits that I have purchased worked very well, and many can be obtained with free shipping, so shop around!? There?s no tuning involved & not really necessary, unless you want to buy some extras & explore further.? As a rule, the larger the coil, the better the audio response... In the case of the really small ones, the audio can be very weak, whereas for the larger units, the audio is of reasonable quality... FYI, there are many preassembled units (some of much larger sizes) available that are quite impressive in my opinion.
>
>
>> On Jan 16, 2019, at 4:25 PM, tesla-request@xxxxxxxxxx wrote:
>>
>> Send Tesla mailing list submissions to
>> ? ? tesla@xxxxxxxxxxxxxxxxxx
>>
>> To subscribe or unsubscribe via the World Wide Web, visit
>> ? ? https://www.pupman.com/mailman/listinfo/tesla
>> or, via email, send a message with subject or body 'help' to
>> ? ? tesla-request@xxxxxxxxxxxxxxxxxx
>>
>> You can reach the person managing the list at
>> ? ? tesla-owner@xxxxxxxxxxxxxxxxxx
>>
>> When replying, please edit your Subject line so it is more specific
>> than "Re: Contents of Tesla digest..."
>>
>>
>> Today's Topics:
>>
>> ? 1. Re: LAPP gas filled condenser, some more info if possible...
>> ? ? ? (homerlea@xxxxxxx)
>> ? 2. Ebay tiny plasma speaker kits (Mr Nico)
>> ? 3. Re: Pole transformer repair (Jan Ohlsson)
>> ? 4. Re: Ebay tiny plasma speaker kits (Allen Bishop)
>> ? 5. Re: LAPP gas filled condenser, some more info if possible...
>> ? ? ? (Allen Bishop)
>> ? 6. Re: Pole transformer repair (Tyler LaVite)
>> ? 7. Re: LAPP gas filled condenser, some more info if possible...
>> ? ? ? (Chris Reeland)
>> ? 8. Re: LAPP gas filled condenser, some more info if possible...
>> ? ? ? (Chris Reeland)
>> ? 9. Let's Get Small (Gary Lau)
>> ? 10. Re: Let's Get Small (jimlux)
>> ? 11. Re: Let's Get Small (derstrom8@xxxxxxx)
>> ? 12. TC Max Spark Length & Output Voltage (William Fox)
>> ? 13. NST Durability (Amnite Ascended)
>> ? 14. Re: NST Durability (Gary Gaspar)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Mon, 14 Jan 2019 04:13:23 +0000 (UTC)
>> From: <homerlea@xxxxxxx>
>> To: tesla@xxxxxxxxxx
>> Subject: Re: [TCML] LAPP gas filled condenser, some more info if
>> ? ? possible...
>> Message-ID: <1337658104.717859.1547439203277@xxxxxxxxxxxxxx>
>> Content-Type: text/plain; charset=UTF-8
>>
>> I bet the gas is supposed to be sulfur hexafluoride like they use for insulation in x-ray equipment.Jim Heagy??-----Original Message-----
>> From: Chris Reeland <chrisreeland@xxxxxxxxx>
>> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>> Sent: Sun, Jan 13, 2019 7:03 pm
>> Subject: [TCML] LAPP gas filled condenser, some more info if possible...
>>
>> Hi all,
>>
>> I am attaching a few pictures of a fairly strange fella that I picked up
>> recently on a small road trip for some REALLY big RF stuff (with some cool
>> radio history behind it, going to be fun to repurpose these items) for a
>> future VTTC project. If any are interested, request and I will post some
>> pictures of these big items. So this gas cap was not intended, but I have
>> it now :-) with the other goodies. Not completely sure if useful yet, but
>> it is really neat and well made for what it is.
>> Not real familiar with gas filled types. Have heard of some made by the
>> usual vacuum capacitor makers offering a few gas filled types. But these
>> are the normal construction type very similar to vacuum caps. This fella is
>> a strange one. See pictures. All I have been able to find is two old
>> magazine ads from the 1940's with next to nothing in real info. If I had to
>> guess, I would say this was made in the 1950's to early 1960's. This LAPP
>> company is a insulator maker with a very long history. And apparently
>> branched out at one time making these strange gas caps also. The biggest
>> surprise so far is that the lower metal case is magnetic. One old ad says
>> for high frequency use, but I am puzzled by the case for this. Usually
>> magnetic materials are frowned upon in RF stuff, so this is a mystery. I
>> originally thought it was aluminum the lower case. It was not until a day
>> later, somehow I decided to try a magnet on it. The bottom of the three
>> feet are not painted, and I can see copper plating. I looked closer at some
>> of the scratches in the body paint and I can see copper plating again. So I
>> can see they are improving conductivity here, since most magnetic things
>> are poor conductors also of course. The upper ring is aluminum. Center
>> electrode is silver plated (not sure of metal yet, but non-magnetic as
>> expected). As you can see very healthy size upper conductors with a "dog
>> bowl" insulator made by LAPP of course. Pretty heavy also weight wise also.
>> Not real large capacitance wise, but may be useful on some other future
>> VTTC project. So just wondering if anyone has possibly any information or
>> maybe a complete LAPP insulator catalog that also list this gas capacitor
>> line it would be greatly appreciated.
>>
>> 4 pictures of it:
>>
>> https://photos.app.goo.gl/zNVKPkrAUqyqnBBj6
>>
>> Thanks,
>>
>> Chris Reeland
>> Ladd Illinois USA
>>
>> Sent from my LG V20
>> _______________________________________________
>> Tesla mailing list
>> Tesla@xxxxxxxxxxxxxxxxxx
>> https://www.pupman.com/mailman/listinfo/tesla
>>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Mon, 14 Jan 2019 06:06:18 +0000
>> From: Mr Nico <nicothefabulous@xxxxxxxxxxx>
>> To: Tesla list <tesla@xxxxxxxxxx>
>> Subject: [TCML] Ebay tiny plasma speaker kits
>> Message-ID:
>> ? ? <BN8PR20MB2306CAD302BB1D504C942933A8800@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
>> ? ?
>> Content-Type: text/plain; charset="us-ascii"
>>
>> So has anyone built one of the tiny plasma speaker kits being sold on ebay?? Good results or junk?? Advice on tuning them?
>>
>> Get Outlook for Android<https://aka.ms/ghei36>
>>
>>
>>
>> ------------------------------
>>
>> Message: 3
>> Date: Mon, 14 Jan 2019 10:03:00 +0100
>> From: "Jan Ohlsson" <jan@xxxxxxxx>
>> To: <tesla@xxxxxxxxxx>
>> Subject: Re: [TCML] Pole transformer repair
>> Message-ID: <01d901d4abe7$f3751a40$da5f4ec0$@eneby.nu>
>> Content-Type: text/plain;? ? charset="us-ascii"
>>
>> Hi Tyler,
>> The growling noise in the clip is from a saturating transformer core.
>> Your setup is very destructive to the transformer, a series resonant circuit
>> where the JL spark gap is a part of the circuit in series with the
>> transformer, ballast and capacitor. There is nothing to remove the energy
>> once the resonance is set up, the ballast feeds more energy from the
>> electric grid continually into the resonance once started. The energy will
>> build up until the core saturates, and then the transformer will go into a
>> chaotic ferroresonance state, that is well known among power distribution
>> engineers to kill transformers. It kills the transformer either by
>> overheating the core, or more prabable in your case, by overvolting the HV
>> winding until it flashes over between adjacent turns.
>>
>> In the usual SGTC setup the tank capacitor is also connected to the
>> transformer and forms a potential resonance circuit, but the regular spark
>> gap, and hopefully also the safety gap, will remove the energy quickly if a
>> resonant condition would occur. In your circuit the JL spark gap can not
>> remove the energy, as it is connected in series inside the resonant circuit.
>>
>>
>> The fact that the spark in the JL gap is weak in the latter part of the clip
>> shows that the energy goes elswhere, in your case into the saturating core
>> losses, and probably also into an internal flashover in the HV winding.
>>
>> Sorry for your loss, but it was a bad setup. Do not use a capacitor in a JL
>> setup, unless there is a safety gap across the transformer HV winding.
>>
>> Jan
>> Stockholm, Sweden
>>
>> --------------------------------------------------
>> Message: 4
>> Date: Thu, 10 Jan 2019 15:41:16 -0600
>> From: Tyler LaVite <tlavite@xxxxxxxxx>
>> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>> Subject: Re: [TCML] Pole transformer repair
>> Message-ID: <64A6EFD9-7FD0-4734-927F-E1DD3A92C32E@xxxxxxxxx>
>> Content-Type: text/plain;? ? charset=utf-8
>>
>> I forgot I had my camera rolling when my transformer messed up.... two
>> things to point out one the arc noise with the cap, two that arc isn?t even
>> remotely close to as large as it normally is without the capacitor, and two
>> notice the loud pop the last time I turn it on and hear the ballast humming
>> loud. That pop would make sense with the one damaged spot I found where the
>> paper was burned and blown out on the outer winding. But fixing that did
>> nothing.
>>
>>
>> https://youtu.be/O21C4Yf9V2E
>>
>>
>>
>>
>>
>>
>> ------------------------------
>>
>> Message: 4
>> Date: Mon, 14 Jan 2019 14:19:58 +0000 (UTC)
>> From: Allen Bishop <co60bishop@xxxxxxx>
>> To: tesla@xxxxxxxxxx
>> Subject: Re: [TCML] Ebay tiny plasma speaker kits
>> Message-ID: <2016857271.18283432.1547475598581@xxxxxxxxxxxxxx>
>> Content-Type: text/plain; charset=UTF-8
>>
>> I have several purchased from ebay and from Banggood in Hong Kong. They work and produce audio but as the description indicates it is tiny.
>> Allen BishopColorado Springs?
>>
>>
>> -----Original Message-----
>> From: Mr Nico <nicothefabulous@xxxxxxxxxxx>
>> To: Tesla list <tesla@xxxxxxxxxx>
>> Sent: Mon, Jan 14, 2019 6:16 am
>> Subject: [TCML] Ebay tiny plasma speaker kits
>>
>> So has anyone built one of the tiny plasma speaker kits being sold on ebay?? Good results or junk?? Advice on tuning them?
>>
>> Get Outlook for Android<https://aka.ms/ghei36>
>>
>> _______________________________________________
>> Tesla mailing list
>> Tesla@xxxxxxxxxxxxxxxxxx
>> https://www.pupman.com/mailman/listinfo/tesla
>>
>>
>> ------------------------------
>>
>> Message: 5
>> Date: Mon, 14 Jan 2019 15:38:22 +0000 (UTC)
>> From: Allen Bishop <co60bishop@xxxxxxx>
>> To: tesla@xxxxxxxxxx
>> Subject: Re: [TCML] LAPP gas filled condenser, some more info if
>> ? ? possible...
>> Message-ID: <1609041818.18304872.1547480302166@xxxxxxxxxxxxxx>
>> Content-Type: text/plain; charset=UTF-8
>>
>> That's a nice cap. I'd love to see photos of the other items you snagged. I left a message on the website where you have the pictures of the cap.?
>> Allen BishopColorado Springsco60bishop@xxxxxxx
>>
>>
>> -----Original Message-----
>> From: Chris Reeland <chrisreeland@xxxxxxxxx>
>> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>> Sent: Sun, Jan 13, 2019 8:03 pm
>> Subject: [TCML] LAPP gas filled condenser, some more info if possible...
>>
>> Hi all,
>>
>> I am attaching a few pictures of a fairly strange fella that I picked up
>> recently on a small road trip for some REALLY big RF stuff (with some cool
>> radio history behind it, going to be fun to repurpose these items) for a
>> future VTTC project. If any are interested, request and I will post some
>> pictures of these big items. So this gas cap was not intended, but I have
>> it now :-) with the other goodies. Not completely sure if useful yet, but
>> it is really neat and well made for what it is.
>> Not real familiar with gas filled types. Have heard of some made by the
>> usual vacuum capacitor makers offering a few gas filled types. But these
>> are the normal construction type very similar to vacuum caps. This fella is
>> a strange one. See pictures. All I have been able to find is two old
>> magazine ads from the 1940's with next to nothing in real info. If I had to
>> guess, I would say this was made in the 1950's to early 1960's. This LAPP
>> company is a insulator maker with a very long history. And apparently
>> branched out at one time making these strange gas caps also. The biggest
>> surprise so far is that the lower metal case is magnetic. One old ad says
>> for high frequency use, but I am puzzled by the case for this. Usually
>> magnetic materials are frowned upon in RF stuff, so this is a mystery. I
>> originally thought it was aluminum the lower case. It was not until a day
>> later, somehow I decided to try a magnet on it. The bottom of the three
>> feet are not painted, and I can see copper plating. I looked closer at some
>> of the scratches in the body paint and I can see copper plating again. So I
>> can see they are improving conductivity here, since most magnetic things
>> are poor conductors also of course. The upper ring is aluminum. Center
>> electrode is silver plated (not sure of metal yet, but non-magnetic as
>> expected). As you can see very healthy size upper conductors with a "dog
>> bowl" insulator made by LAPP of course. Pretty heavy also weight wise also.
>> Not real large capacitance wise, but may be useful on some other future
>> VTTC project. So just wondering if anyone has possibly any information or
>> maybe a complete LAPP insulator catalog that also list this gas capacitor
>> line it would be greatly appreciated.
>>
>> 4 pictures of it:
>>
>> https://photos.app.goo.gl/zNVKPkrAUqyqnBBj6
>>
>> Thanks,
>>
>> Chris Reeland
>> Ladd Illinois USA
>>
>> Sent from my LG V20
>> _______________________________________________
>> Tesla mailing list
>> Tesla@xxxxxxxxxxxxxxxxxx
>> https://www.pupman.com/mailman/listinfo/tesla
>>
>>
>> ------------------------------
>>
>> Message: 6
>> Date: Mon, 14 Jan 2019 07:40:38 -0600
>> From: Tyler LaVite <tlavite@xxxxxxxxx>
>> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>> Subject: Re: [TCML] Pole transformer repair
>> Message-ID: <02680B47-286A-41ED-AD08-F9B91295BC55@xxxxxxxxx>
>> Content-Type: text/plain;? ? charset=us-ascii
>>
>> Thank you for that response that makes sense now! I have since pulled the core out and rewound the transformer and brought it back to life so she lives on! Lol
>>
>> Sent from my iPhone
>>
>>> On Jan 14, 2019, at 3:03 AM, Jan Ohlsson <jan@xxxxxxxx> wrote:
>>>
>>> Hi Tyler,
>>> The growling noise in the clip is from a saturating transformer core.
>>> Your setup is very destructive to the transformer, a series resonant circuit
>>> where the JL spark gap is a part of the circuit in series with the
>>> transformer, ballast and capacitor. There is nothing to remove the energy
>>> once the resonance is set up, the ballast feeds more energy from the
>>> electric grid continually into the resonance once started. The energy will
>>> build up until the core saturates, and then the transformer will go into a
>>> chaotic ferroresonance state, that is well known among power distribution
>>> engineers to kill transformers. It kills the transformer either by
>>> overheating the core, or more prabable in your case, by overvolting the HV
>>> winding until it flashes over between adjacent turns.
>>>
>>> In the usual SGTC setup the tank capacitor is also connected to the
>>> transformer and forms a potential resonance circuit, but the regular spark
>>> gap, and hopefully also the safety gap, will remove the energy quickly if a
>>> resonant condition would occur. In your circuit the JL spark gap can not
>>> remove the energy, as it is connected in series inside the resonant circuit.
>>>
>>>
>>> The fact that the spark in the JL gap is weak in the latter part of the clip
>>> shows that the energy goes elswhere, in your case into the saturating core
>>> losses, and probably also into an internal flashover in the HV winding.
>>>
>>> Sorry for your loss, but it was a bad setup. Do not use a capacitor in a JL
>>> setup, unless there is a safety gap across the transformer HV winding.
>>>
>>> Jan
>>> Stockholm, Sweden
>>>
>>> --------------------------------------------------
>>> Message: 4
>>> Date: Thu, 10 Jan 2019 15:41:16 -0600
>>> From: Tyler LaVite <tlavite@xxxxxxxxx>
>>> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>>> Subject: Re: [TCML] Pole transformer repair
>>> Message-ID: <64A6EFD9-7FD0-4734-927F-E1DD3A92C32E@xxxxxxxxx>
>>> Content-Type: text/plain;? ? charset=utf-8
>>>
>>> I forgot I had my camera rolling when my transformer messed up.... two
>>> things to point out one the arc noise with the cap, two that arc isn?t even
>>> remotely close to as large as it normally is without the capacitor, and two
>>> notice the loud pop the last time I turn it on and hear the ballast humming
>>> loud. That pop would make sense with the one damaged spot I found where the
>>> paper was burned and blown out on the outer winding. But fixing that did
>>> nothing.
>>>
>>>
>>> https://youtu.be/O21C4Yf9V2E
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> Tesla mailing list
>>> Tesla@xxxxxxxxxxxxxxxxxx
>>> https://www.pupman.com/mailman/listinfo/tesla
>>
>>
>> ------------------------------
>>
>> Message: 7
>> Date: Tue, 15 Jan 2019 03:23:29 -0600
>> From: Chris Reeland <chrisreeland@xxxxxxxxx>
>> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>> Subject: Re: [TCML] LAPP gas filled condenser, some more info if
>> ? ? possible...
>> Message-ID:
>> ? ? <CAPVCm=OLNd0MqL=8Hst26on9G9vW1H30Oy7drX+3tVW77YHO6w@xxxxxxxxxxxxxx>
>> Content-Type: text/plain; charset="UTF-8"
>>
>> Hi Jim,
>>
>> As far as I know it is filled with nitrogen.
>> I have found just a little info in one my best capacitor books from 1960.
>> Not much real info, but there is a graph showing the breakdown potential
>> vs. nitrogen pressures. It agrees spot on with the nameplate info.
>>
>> Chris Reeland
>> Ladd Illinois USA
>>
>> Sent from my LG V20
>>
>>
>> ------------------------------
>>
>> Message: 8
>> Date: Tue, 15 Jan 2019 04:46:41 -0600
>> From: Chris Reeland <chrisreeland@xxxxxxxxx>
>> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>> Subject: Re: [TCML] LAPP gas filled condenser, some more info if
>> ? ? possible...
>> Message-ID:
>> ? ? <CAPVCm=PmiPTqMpeVvMe=raGs=rKx04W_kB6fvD3YcmYBcQo7iQ@xxxxxxxxxxxxxx>
>> Content-Type: text/plain; charset="UTF-8"
>>
>> Hi Allen,
>>
>> Sorry for the delayed response, I work second shift at my job. Since you
>> asked I will post a few pictures. This little road trip was actually the
>> second time I have went for these bigger RF things at the same place. First
>> trip was in late November. I will include a few pictures also from this
>> one. These are some pretty old spares kept by technicians after several
>> upgrades over the years at a 50,000 Watt AM radio station. Going to also do
>> some other experimenting with this stuff besides coil use, since I have
>> extras also now.
>>
>> Pictures:
>>
>> https://photos.app.goo.gl/n853CYh4YzpzXadK7
>>
>> Some comments on the 3 vacuum variable caps and the 2 coils:
>>
>> These vacuum variable caps are all older types of course as seen by the
>> glass. New types are ceramic housed. The "smaller blue" one is a bit newer
>> for an old type compared to the other two much older bigger fellas.
>>
>> The blue one is a maximum of 650pF at a rating of 55KV.
>>
>> The bigger much older one next to it is a 1000pF max @ 45KV.
>>
>> Then the third one in different picture is near indentical to the other big
>> one, but a little lower voltage, 1000pF max @ 35KV.
>>
>> The two big coils are very similar, one is just a little shorter. Same
>> diameter and made by the same company, whoever that was...it is unknown.
>> Definitely both are very old. The slightly bigger one if you look closely
>> at it, you can see some outer supports for another winding which is long
>> since gone now. I am sure on both of these the insulating supports are made
>> of a very good material, but again this is unknown of what. Most likely
>> some kind of composite, possibly some of this is nasty of course. But it is
>> fine as long you don't cut/grind on it of course. Anyways, I never need to,
>> it is all done, ready as is...
>> Also just a note... notice the outer support rings on both coils, which are
>> made of cast aluminum, there is a gap in each one...
>>
>> Going to be fun repurposing this older stuff and experimenting. Just like I
>> enjoy using my tubes also...
>>
>> Also eventually I will have some updates on my little 304 VTTC eventually
>> and I will post some things. As you can see I got sidetracked recently and
>> I have been also been busy with some of my heavy iron metal working
>> equipment. Back to the 304, I will mention some more things about how my
>> grid leak circuit behaves for me. And I will finally scope some things,
>> mainly the grid. Curious of some things here also. And I have tested two
>> more recently acquired tubes. Came across another very unusual one.
>> Definitely going to scope this one.
>>
>> Okay, till later, when I have a chance...
>>
>> Chris Reeland
>> Ladd Illinois USA
>>
>> Sent from my LG V20
>>
>>
>> ------------------------------
>>
>> Message: 9
>> Date: Tue, 15 Jan 2019 20:08:10 -0500
>> From: Gary Lau <glau1024@xxxxxxxxx>
>> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>> Subject: [TCML] Let's Get Small
>> Message-ID:
>> ? ? <CAKV84bYejTRbtHUqa0bcwUGeNaFF9tqWdpnzfRWhe3t32cq+hg@xxxxxxxxxxxxxx>
>> Content-Type: text/plain; charset="UTF-8"
>>
>> With apologies to Steve Martin, I was hoping to inspire some discussion on
>> the small end of the Tesla Coil spectrum.? Not to suggest it's easy but
>> everyone knows if you throw 10KVA into a coil, you're eventually going to
>> get some big sparks.? Not much has been shared about the other end of the
>> spectrum.
>>
>> Several years ago I threw together a palm-top sized coil powered by a yard
>> sale bug zapper transformer.? Bug zapper transformers are built just like
>> NST's, current limited but tiny.? Inspired by the recent Little Coil
>> thread, I dusted it off and made some primary coil tweaks and adjustments,
>> and finally got around to taking some pictures.? The performance is OK-ish,
>> maybe 2" to a nearby screwdriver, but I was really hoping to get some
>> similar sized sparks just wandering about the topload.? Yeah I have plans
>> to tweak some more, although such a small 4-turn primary is difficult to
>> adjust.? Looking for that round tuit.
>>
>> Well, I was hoping to hear other successes in the micro-sized league and
>> what might be attainable.
>>
>> Pictures and a short video are at:
>> https://drive.google.com/open?id=1q83wHgtXXlpcKSobd8bXSQ1ZlmvlK3zp
>>
>> Specs:
>>
>> Power source: 4.8kV/8.7mA Bug Zapper Transformer, modified to remove the
>> potted built-in ceramic capacitor across the secondary.
>>
>> Primary C: .0094uF/8KV MMC (5x 47nF/1600V)
>> Primary L: Helical 4 turns PVC insulated 18AWG solid wire
>>
>> Secondary L: 0.84?D x 4.43?L x #38AWG ? 3.37mH
>> Top load: Pine disk, turned on drill press to form .75? x 3.4?
>> pseudo-toroid, Al tape covered
>>
>> Spark gap: Single cylinder gap, .020? separation
>>
>> Performance: 2.25? to a screwdriver blade (very little tuning performed)
>>
>> Regards, Gary Lau
>> MA, USA
>>
>>
>> ------------------------------
>>
>> Message: 10
>> Date: Tue, 15 Jan 2019 17:24:10 -0800
>> From: jimlux <jimlux@xxxxxxxxxxxxx>
>> To: tesla@xxxxxxxxxxxxxxxxxx
>> Subject: Re: [TCML] Let's Get Small
>> Message-ID: <84dc0198-cd4f-e449-25db-bac2ba24066e@xxxxxxxxxxxxx>
>> Content-Type: text/plain; charset=utf-8; format=flowed
>>
>>> On 1/15/19 5:08 PM, Gary Lau wrote:
>>> With apologies to Steve Martin, I was hoping to inspire some discussion on
>>> the small end of the Tesla Coil spectrum.? Not to suggest it's easy but
>>> everyone knows if you throw 10KVA into a coil, you're eventually going to
>>> get some big sparks.? Not much has been shared about the other end of the
>>> spectrum.
>>>
>>> Several years ago I threw together a palm-top sized coil powered by a yard
>>> sale bug zapper transformer.? Bug zapper transformers are built just like
>>> NST's, current limited but tiny.
>>
>>
>> there's also the GMHEICSLR one can work on - basically driving a GM HEI
>> ignition coil off 110V line.
>> 1 foot sparks are possible..
>>
>> http://www.powerlabs.org/gmheicslr.htm has a story by Sam Barros from
>> 2010 illustrating his ideas. Sam has moved on to other things (if you
>> need your GT-R tuned or enhanced, he's a guy to talk to), although I
>> suspect he might have his old coils laying around.
>>
>>
>> There's also some old posts on 4hv.org
>> https://4hv.org/e107_plugins/forum/forum_viewtopic.php?3205
>>
>>
>>
>>
>>
>>
>>
>> ------------------------------
>>
>> Message: 11
>> Date: Wed, 16 Jan 2019 01:59:40 +0000 (UTC)
>> From: <derstrom8@xxxxxxx>
>> To: tesla@xxxxxxxxxx
>> Subject: Re: [TCML] Let's Get Small
>> Message-ID: <2057464314.227136.1547603980689@xxxxxxxxxxxxxx>
>> Content-Type: text/plain; charset=UTF-8
>>
>> Speaking of small Tesla coils -?
>> One of my very first was made out of junk (I didn't spend a penny on it) and it stood only about four inches high. It used wire from an old microwave oven fan motor wound around a toilet paper tube for the secondary, and there was no topload. The primary consisted of just a few turns (4-6?) of bare copper ground wire removed from a section of 12-2 Romex residential cable, and it was set up on bottle caps at the base of the secondary. The capacitor was a single beer bottle wrapped in aluminum foil and filled with salt water. The capacitance measured about 0.5nF, if I remember correctly. I used a static spark gap (I believe it was 6 or 7 sections of copper tube mounted next to each other on a hard plastic VHS case) and the whole thing was connected to a 9kV 60mA NST.
>> https://www.youtube.com/watch?v=xvIowPqcWek
>> Looking back, I realize that the fact that it worked at all was sheer luck - I did not do any math whatsoever when I built this coil and I had absolutely no idea what I was doing. Nonetheless this build really sparked my interest (no pun intended) in Tesla coil building and brought me to where I am today. Despite its horrible design and assembly, I'm still fairly proud of this little coil, though if I ever tried to replicate it I can guarantee it would never work the same.
>> Regards,
>> Matt Lewis, Fairlee VT
>>
>>
>> -----Original Message-----
>> From: Gary Lau <glau1024@xxxxxxxxx>
>> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>> Sent: Tue, Jan 15, 2019 8:09 pm
>> Subject: [TCML] Let's Get Small
>>
>> With apologies to Steve Martin, I was hoping to inspire some discussion on
>> the small end of the Tesla Coil spectrum.? Not to suggest it's easy but
>> everyone knows if you throw 10KVA into a coil, you're eventually going to
>> get some big sparks.? Not much has been shared about the other end of the
>> spectrum.
>>
>> Several years ago I threw together a palm-top sized coil powered by a yard
>> sale bug zapper transformer.? Bug zapper transformers are built just like
>> NST's, current limited but tiny.? Inspired by the recent Little Coil
>> thread, I dusted it off and made some primary coil tweaks and adjustments,
>> and finally got around to taking some pictures.? The performance is OK-ish,
>> maybe 2" to a nearby screwdriver, but I was really hoping to get some
>> similar sized sparks just wandering about the topload.? Yeah I have plans
>> to tweak some more, although such a small 4-turn primary is difficult to
>> adjust.? Looking for that round tuit.
>>
>> Well, I was hoping to hear other successes in the micro-sized league and
>> what might be attainable.
>>
>> Pictures and a short video are at:
>> https://drive.google.com/open?id=1q83wHgtXXlpcKSobd8bXSQ1ZlmvlK3zp
>>
>> Specs:
>>
>> Power source: 4.8kV/8.7mA Bug Zapper Transformer, modified to remove the
>> potted built-in ceramic capacitor across the secondary.
>>
>> Primary C: .0094uF/8KV MMC (5x 47nF/1600V)
>> Primary L: Helical 4 turns PVC insulated 18AWG solid wire
>>
>> Secondary L: 0.84?D x 4.43?L x #38AWG ? 3.37mH
>> Top load: Pine disk, turned on drill press to form .75? x 3.4?
>> pseudo-toroid, Al tape covered
>>
>> Spark gap: Single cylinder gap, .020? separation
>>
>> Performance: 2.25? to a screwdriver blade (very little tuning performed)
>>
>> Regards, Gary Lau
>> MA, USA
>> _______________________________________________
>> Tesla mailing list
>> Tesla@xxxxxxxxxxxxxxxxxx
>> https://www.pupman.com/mailman/listinfo/tesla
>>
>>
>> ------------------------------
>>
>> Message: 12
>> Date: Tue, 15 Jan 2019 21:08:46 -0500
>> From: William Fox <wm9fox@xxxxxxxxx>
>> To: tesla@xxxxxxxxxxxxxxxxxx
>> Subject: [TCML] TC Max Spark Length & Output Voltage
>> Message-ID: <419492AB-7182-4979-A6A3-A0771C9F750D@xxxxxxxxx>
>> Content-Type: text/plain;? ? charset=utf-8
>>
>> Hello Everyone,
>>
>> There has been much discussion over the decades about estimating maximum TC spark length & corresponding voltage... To my knowledge, much investigation has been done by our fellow members, John Freau (Length= 1.7 * SQRT(kVA in) & Greg Leyh V = 200 kV/m)... Thanks, guys!? But with the advent of so many different types of TC?s beyond the SGTC (e.g. Class E, DRSSTC, QRSSTC, SSTC, VTTC, etc.) these issues are getting much more complicated.? It would be very interesting, if those who are much more knowledgeable in this area than I, take a shot at tabulating field data & see if, from that data, some equations of approximation might be derived.? Assuming discharge is issuing from a breakout point on topload or pointed terminal.? For example, QRSSTC?s maintain the arc channel longer, time-wise, allowing the discharge to grow to 5 feet or so from a very short, squatty coil, but actual voltage as low as 75 kV (this from offline discussion with Bert Hickman)... Thanks, Bert!? What do
> yo
>> u members have to say about this?
>>
>> Thanks,
>>
>> Bill
>>
>> Sent by Ma?ak's humble servant.
>>
>> ------------------------------
>>
>> Message: 13
>> Date: Wed, 16 Jan 2019 07:47:34 -0700
>> From: Amnite Ascended <jeremiahschmidt1018@xxxxxxxxx>
>> To: tesla@xxxxxxxxxxxxxxxxxx
>> Subject: [TCML] NST Durability
>> Message-ID:
>> ? ? <CAHRoP7A3aehQdFMnae4BRJe3fgXoxtjvWY6tk2eyYgYhAK6RDg@xxxxxxxxxxxxxx>
>> Content-Type: text/plain; charset="UTF-8"
>>
>> Sorry if your first thought was, "Jesus man.... Millionth time...
>> Fragile...."
>>
>> Anywho. So I want to see if a whole, working, NST will survive getting
>> powder coated. My main concern is the windings insulation.
>>
>> For those unfamiliar with the process, here is a quick overview.
>> The NST will get sandblasted. Then hung on a rack. The rack and NST will
>> then be grounded. The powder is charged so it easily sticks to the grounded
>> object. Then the NST will be heat treated to melt and bond the powder. This
>> is sticking it in an oven for 20-40 minutes, at temps between 325-425 f.
>> Lugs will of course been protected. The tar smell/smoke shouldn't be an
>> issue.
>>
>> I've never unpotted one of these, so seeking the experiences of the list.
>>
>> Thanks,
>> Jeremiah
>>
>>
>> ------------------------------
>>
>> Message: 14
>> Date: Wed, 16 Jan 2019 20:05:41 +0000 (UTC)
>> From: Gary Gaspar <majrombus@xxxxxxxxxxxxx>
>> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>> Subject: Re: [TCML] NST Durability
>> Message-ID: <279762191.650846.1547669141355@xxxxxxxxxxxxxx>
>> Content-Type: text/plain; charset=UTF-8
>>
>> I have never done this Melted out the tar I would just drop the whole thing in a plastic tub full of the right OIL In the past you were able to buy a new NST bare just the iron & coils. I have a small one like 9kv I can not remember if they went all the way to the big ones I had a Blue Jefferson one15kv @ 120 ma now I have 8 15kv @ 30s that were bought new in the early 90s. Have lost 1 I know of in that time. Lost a pole. I use 4 now to run a coil I think the choke coils between the NST & cap are made to small I get good results from a choke on each pole of a NST my form is 1 inch diameter by 1 foot3 layers with shrink sleeve over each layer of wire I used some magnet wire that was handy like 22 or so close wound about 100+ turns a layer. Grounds on the transformers are floating. The case will have some high voltage better for the transformer but not you if you like to touch them when they are HOT. I do have a Ground Rod10 foot rod & welding cable to bottom of tesla coil &
> s
>> afety gap..? ? On Wednesday, January 16, 2019, 07:08:44 AM PST, Amnite Ascended <jeremiahschmidt1018@xxxxxxxxx> wrote:?
>>
>> Sorry if your first thought was, "Jesus man.... Millionth time...
>> Fragile...."
>>
>> Anywho. So I want to see if a whole, working, NST will survive getting
>> powder coated. My main concern is the windings insulation.
>>
>> For those unfamiliar with the process, here is a quick overview.
>> The NST will get sandblasted. Then hung on a rack. The rack and NST will
>> then be grounded. The powder is charged so it easily sticks to the grounded
>> object. Then the NST will be heat treated to melt and bond the powder. This
>> is sticking it in an oven for 20-40 minutes, at temps between 325-425 f.
>> Lugs will of course been protected. The tar smell/smoke shouldn't be an
>> issue.
>>
>> I've never unpotted one of these, so seeking the experiences of the list.
>>
>> Thanks,
>> Jeremiah
>> _______________________________________________
>> Tesla mailing list
>> Tesla@xxxxxxxxxxxxxxxxxx
>> https://www.pupman.com/mailman/listinfo/tesla
>>
>>
>> ------------------------------
>>
>> Subject: Digest Footer
>>
>> _______________________________________________
>> Tesla mailing list
>> Tesla@xxxxxxxxxxxxxxxxxx
>> https://www.pupman.com/mailman/listinfo/tesla
>>
>>
>> ------------------------------
>>
>> End of Tesla Digest, Vol 134, Issue 7
>> *************************************
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxxxxxx
> https://www.pupman.com/mailman/listinfo/tesla
>
>
>
>
> ------------------------------
>
> Message: 3
> Date: Thu, 17 Jan 2019 11:44:51 -0800
> From: jimlux <jimlux@xxxxxxxxxxxxx>
> To: tesla@xxxxxxxxxxxxxxxxxx
> Subject: [TCML] max spark length
> Message-ID: <acd46224-f130-f05b-c638-918516bb37af@xxxxxxxxxxxxx>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
>> On 1/16/19 3:42 PM, hooverrl@xxxxxxxxxxxxxx wrote:
>> Message: 12
>> Date: Tue, 15 Jan 2019 21:08:46 -0500
>> From: William Fox <wm9fox@xxxxxxxxx>
>> To: tesla@xxxxxxxxxxxxxxxxxx
>> Subject: [TCML] TC Max Spark Length & Output Voltage
>> Message-ID: <419492AB-7182-4979-A6A3-A0771C9F750D@xxxxxxxxx>
>> Content-Type: text/plain; charset=utf-8
>>
>> Hello,
>>
>> My experience working with high voltage Marx generators (DC uni-potential
>> only devices) showed 100 kV/ft was a good clearance distance for a rod gap
>> or capacitor case to mounting frame. This indicated that a sparkover could
>> occur ~125 kV/ft. Therefore, an 8-ft gap would not likely exceed 1 million
>> volts through air. Experience saw a surface flashover of a 13-ft insulator
>> with ribbed convolutions (skirts or petticoats), at 2.1 million volts (slow
>> switching surge) where the flash occurred over the entire insulator string.
>> At 2.05 million volts, we only saw streamers protruding from the end
>> electrodes. Since that was negative polarity at the power end, when
>> reversing the polarity to positive saw a significant drop in flashover
>> voltage (down to 1.8 million volts) due to clear sparkover, where the higher
>> voltage flashover more closely followed the contours of the insulator.
>>
>
>
> 10kV/inch is a similar guideline.. but it starts to breakdown [sic]
> around 200-300 kV...
>
> For long sparks, it's about field uniformity, and streamer/leader length
> - just like lightning, and whether you can keep the channel hot.
>
> That's why the "clearance guidelines" for EHV transmission lines deviate
> from a "feet/kilovolt" kind of thing.
>
> Bazelyan and Raizer have a fair amount of detail on this..
>
>
> ------------------------------
>
> Message: 4
> Date: Thu, 17 Jan 2019 12:38:36 +0100
> From: "Udo Lenz" <udo_lenz@xxxxxxxxxxxxxx>
> To: "William Fox" <wm9fox@xxxxxxxxx>, <tesla@xxxxxxxxxxxxxxxxxx>
> Subject: Re: [TCML] TC Max Spark Length & Output Voltage
> Message-ID: <09792ACD27944F378C074745A57A9AC3@UdosLaptop>
> Content-Type: text/plain; format=flowed; charset="UTF-8";
> reply-type=original
>
> Arc voltages come in a wide range. For a spark gap with rounded
> electrodes you need about 30kV per cm for a spark to fire.
> In an arc lamp, voltages around a 100V for a 1cm gap are sufficient.
> An arc lamp has to be ignited, though, e.g. in an antique carbon lamp,
> the electrodes first are touching and then pulled apart.
>
> The difference between these 2 situations results from the way,
> free electrons, which are the carriers of conductivity, are created.
>
> In the spark gap, free electrons have to be accelerated by the electric field
> against the resistance of air molecules to be able to hit air
> molecules fast enough to liberate new electrons from them.
> That causes an avalanche of electrons and requires high voltages.
>
> In an arc lamp, electrons are liberated by high temperature
> air molecules hitting each other. Thus voltage (and current)
> is required only to keep the air hot enough.
>
> Tesla coil arcs are special, because they can end in mid air.
> Once the arc breaks out, which requires several tens of kV
> by the means of electron acceleration, it produces a plasma
> channel. The once created plasma channel has a lot lower
> voltage drop such as in an arc lamp.
>
> That channel transports most of the top load voltage to the tip of
> the arc, so that it can grow from there. A TC arc is a mixture
> of both the arc lamp and spark gap situations, i.e. around 100V/cm near
> the breakout point and 30kV/cm at the arc tip.
>
> The voltage-length relationship in a TC arc is complicated. It also
> depends on the duration of the burst, since arc growth takes some
> time. Also involved is the frequency of the coil. A higher frequency
> will cause more charge movement along the arc, increasing power
> dissipation along the arc, which implies a better conductivity of it.
> So less voltage is then required for a given arc length.
>
> Udo
>
>
> ----- Original Message -----
> From: "William Fox" <wm9fox@xxxxxxxxx>
> To: <tesla@xxxxxxxxxxxxxxxxxx>
> Sent: Wednesday, January 16, 2019 3:08 AM
> Subject: [TCML] TC Max Spark Length & Output Voltage
>
>
> Hello Everyone,
>
> There has been much discussion over the decades about estimating maximum TC spark length & corresponding voltage... To my knowledge,
> much investigation has been done by our fellow members, John Freau (Length= 1.7 * SQRT(kVA in) & Greg Leyh V = 200 kV/m)... Thanks,
> guys! But with the advent of so many different types of TC?s beyond the SGTC (e.g. Class E, DRSSTC, QRSSTC, SSTC, VTTC, etc.) these
> issues are getting much more complicated. It would be very interesting, if those who are much more knowledgeable in this area than
> I, take a shot at tabulating field data & see if, from that data, some equations of approximation might be derived. Assuming
> discharge is issuing from a breakout point on topload or pointed terminal. For example, QRSSTC?s maintain the arc channel longer,
> time-wise, allowing the discharge to grow to 5 feet or so from a very short, squatty coil, but actual voltage as low as 75 kV (this
> from offline discussion with Bert Hickman)... Thanks, Bert! What do you members have to say about this?
>
> Thanks,
>
> Bill
>
> Sent by Ma?ak's humble servant.
>
>
>
> ------------------------------
>
> Message: 5
> Date: Thu, 17 Jan 2019 13:40:39 -0500
> From: William Fox <wm9fox@xxxxxxxxx>
> To: Udo Lenz <udo_lenz@xxxxxxxxxxxxxx>
> Cc: tesla@xxxxxxxxxxxxxxxxxx
> Subject: Re: [TCML] TC Max Spark Length & Output Voltage
> Message-ID: <BD9AAF74-B632-405B-AE12-736135E04E3A@xxxxxxxxx>
> Content-Type: text/plain; charset=utf-8
>
> Dear Udo,
>
> Thank-you very much for your detailed explanation of the plasma channel, how it is created & how it allows the discharge to grow.
>
> Obviously you have much experience in this phenomenon, and have analyzed it in much detail.
>
> Now I can appreciate how much more complicated the arc length vs. voltage is than I ever could have imagined!
>
> So, again, I thank you very much for the time and effort you took to field my question!
>
> Best regards,
>
> Bill
>
> Sent by Ma?ak's humble servant.
>
>> On Jan 17, 2019, at 6:38 AM, Udo Lenz <udo_lenz@xxxxxxxxxxxxxx> wrote:
>>
>> Arc voltages come in a wide range. For a spark gap with rounded
>> electrodes you need about 30kV per cm for a spark to fire.
>> In an arc lamp, voltages around a 100V for a 1cm gap are sufficient.
>> An arc lamp has to be ignited, though, e.g. in an antique carbon lamp,
>> the electrodes first are touching and then pulled apart.
>>
>> The difference between these 2 situations results from the way,
>> free electrons, which are the carriers of conductivity, are created.
>>
>> In the spark gap, free electrons have to be accelerated by the electric field
>> against the resistance of air molecules to be able to hit air
>> molecules fast enough to liberate new electrons from them.
>> That causes an avalanche of electrons and requires high voltages.
>>
>> In an arc lamp, electrons are liberated by high temperature
>> air molecules hitting each other. Thus voltage (and current)
>> is required only to keep the air hot enough.
>>
>> Tesla coil arcs are special, because they can end in mid air.
>> Once the arc breaks out, which requires several tens of kV
>> by the means of electron acceleration, it produces a plasma
>> channel. The once created plasma channel has a lot lower
>> voltage drop such as in an arc lamp.
>>
>> That channel transports most of the top load voltage to the tip of
>> the arc, so that it can grow from there. A TC arc is a mixture
>> of both the arc lamp and spark gap situations, i.e. around 100V/cm near
>> the breakout point and 30kV/cm at the arc tip.
>>
>> The voltage-length relationship in a TC arc is complicated. It also
>> depends on the duration of the burst, since arc growth takes some
>> time. Also involved is the frequency of the coil. A higher frequency
>> will cause more charge movement along the arc, increasing power
>> dissipation along the arc, which implies a better conductivity of it.
>> So less voltage is then required for a given arc length.
>>
>> Udo
>>
>>
>> ----- Original Message ----- From: "William Fox" <wm9fox@xxxxxxxxx>
>> To: <tesla@xxxxxxxxxxxxxxxxxx>
>> Sent: Wednesday, January 16, 2019 3:08 AM
>> Subject: [TCML] TC Max Spark Length & Output Voltage
>>
>>
>> Hello Everyone,
>>
>> There has been much discussion over the decades about estimating maximum TC spark length & corresponding voltage... To my knowledge,
>> much investigation has been done by our fellow members, John Freau (Length= 1.7 * SQRT(kVA in) & Greg Leyh V = 200 kV/m)... Thanks,
>> guys! But with the advent of so many different types of TC?s beyond the SGTC (e.g. Class E, DRSSTC, QRSSTC, SSTC, VTTC, etc.) these
>> issues are getting much more complicated. It would be very interesting, if those who are much more knowledgeable in this area than
>> I, take a shot at tabulating field data & see if, from that data, some equations of approximation might be derived. Assuming
>> discharge is issuing from a breakout point on topload or pointed terminal. For example, QRSSTC?s maintain the arc channel longer,
>> time-wise, allowing the discharge to grow to 5 feet or so from a very short, squatty coil, but actual voltage as low as 75 kV (this
>> from offline discussion with Bert Hickman)... Thanks, Bert! What do you members have to say about this?
>>
>> Thanks,
>>
>> Bill
>>
>> Sent by Ma?ak's humble servant.
>>
>
>
> ------------------------------
>
> Message: 6
> Date: Thu, 17 Jan 2019 14:58:41 -0600
> From: Amnite Ascended <jeremiahschmidt1018@xxxxxxxxx>
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Subject: Re: [TCML] NST Durability
> Message-ID:
> <CAHRoP7CHYLB4J-nU5TMHxC5fjH3wfYU7TX9SOHVSWu_tohwQuA@xxxxxxxxxxxxxx>
> Content-Type: text/plain; charset="UTF-8"
>
> I worked in powder coating for 4 years. I can do it all for free, at my
> leisure. Hence why I was curious about it. Plus the Silver hammertone
> powder is suuuuppper sexy. I have two nsts with one of hv ends shorted I'll
> test it out on first. I'm glad to hear 20-40 minutes wouldn't start the tar
> melting, but am slightly concerned with the brought up heat absorbtion... I
> suppose like all tinkerers, i'm going to have to put the math aside and
> just do it.
>
>> On Wed, Jan 16, 2019, 4:39 PM Daniel Kunkel <dankunkel@xxxxxxxxx wrote:
>>
>> Jeremiah,
>> Why not save money and just use regular paint? I have been hooked on
>> painting things with a hammered finish lately.
>>
>> https://www.amazon.com/dp/B0002YVWJW/ref=twister_B07FYRW8QP?_encoding=UTF8&th=1
>>
>> If you are really stuck on the powder coat, then at least send a dead NST
>> through the process first. You don't even need to coat it and pay for it.
>> Surely they would let you stick in a plain NST in the oven for free just to
>> see if it survives.
>>
>>
>> ~Dan (yes I painted my kids pinewood derby car in gold hammered finish)
>> Kansas City area
>> _______________________________________________
>> Tesla mailing list
>> Tesla@xxxxxxxxxxxxxxxxxx
>> https://www.pupman.com/mailman/listinfo/tesla
>>
>
>
> ------------------------------
>
> Message: 7
> Date: Fri, 18 Jan 2019 14:10:45 +0800
> From: "Peter Terren" <pterren@xxxxxxxxxxxx>
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Subject: Re: [TCML] Let's Get Small
> Message-ID: <7A511D9AF478460FA32ECD745F91C379@Peter2018Home>
> Content-Type: text/plain; format=flowed; charset="UTF-8";
> reply-type=original
>
> I made a Tesla coil out of ONLY parts from a microwave oven, hotglue and
> solder.
> Details here including photos:
> https://plus.google.com/u/0/+PeterTerren/posts/FnGcdK5773d
>
> "This Tesla coil is made only from parts from a single microwave oven.
> It was part of a challenge to the 4HV community to see who could make one
> first.
> Here are the tech details. The microwave oven transformer supplies 2000VAC
> which is voltage doubled with the 140 nF capacitor and diode to around
> 3,500VDC. The primary winding came from the 6Volt heater winding from the
> main transformer. The very fine Tesla coil secondary wire came from the fan
> motor windings and is supported by the triangular wheel platter support.
> The spark gap was constructed from a stripped circuit board and some
> aluminium strips.
> So what about the capacitors here? The tricky part was to open the original
> 1uF oil filled capacitor and unroll windings then reconnect them to form a a
> 140nf 3.5kV capacitor for the doubler and the main Tesla tank cap of 1nF at
> perhaps 10kV. Plus the original cardboard former was taken out washed and
> used as the secondary former.
> It worked. The capacitors died fairly quickly but proof of principle was
> established."
> Even had some racing sparks.
>
>
> --------------------------------------------------
> From: "Gary Gaspar" <majrombus@xxxxxxxxxxxxx>
> Sent: Thursday, January 17, 2019 4:26 AM
> To: <tesla@xxxxxxxxxx>; <derstrom8@xxxxxxx>
> Subject: Re: [TCML] Let's Get Small
>
>> Gary Lau
>> An inspiration for me to try the same my neighbor threw out his very old
>> bug zapper a while back & now I can do something with it. Cool On
>> Tuesday, January 15, 2019, 06:10:38 PM PST, derstrom8--- via Tesla
>> <tesla@xxxxxxxxxx> wrote:
>>
>> Speaking of small Tesla coils -
>> One of my very first was made out of junk (I didn't spend a penny on it)
>> and it stood only about four inches high. It used wire from an old
>> microwave oven fan motor wound around a toilet paper tube for the
>> secondary, and there was no topload. The primary consisted of just a few
>> turns (4-6?) of bare copper ground wire removed from a section of 12-2
>> Romex residential cable, and it was set up on bottle caps at the base of
>> the secondary. The capacitor was a single beer bottle wrapped in aluminum
>> foil and filled with salt water. The capacitance measured about 0.5nF, if
>> I remember correctly. I used a static spark gap (I believe it was 6 or 7
>> sections of copper tube mounted next to each other on a hard plastic VHS
>> case) and the whole thing was connected to a 9kV 60mA NST.
>> https://www.youtube.com/watch?v=xvIowPqcWek
>> Looking back, I realize that the fact that it worked at all was sheer
>> luck - I did not do any math whatsoever when I built this coil and I had
>> absolutely no idea what I was doing. Nonetheless this build really sparked
>> my interest (no pun intended) in Tesla coil building and brought me to
>> where I am today. Despite its horrible design and assembly, I'm still
>> fairly proud of this little coil, though if I ever tried to replicate it I
>> can guarantee it would never work the same.
>> Regards,
>> Matt Lewis, Fairlee VT
>>
>>
>
>
>
> ------------------------------
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> End of Tesla Digest, Vol 134, Issue 9
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