Thank you Steve and Gary for the insighht add encouragement!
~Dan
Kansas City area
On Wed, Feb 21, 2018, 7:04 AM Steve White <steve.white1@xxxxxxxxx> wrote:
> Looks pretty good to me. There is nothing wrong with wood as long as it is
> used in the proper places such as for structural elements as you have done.
> Just don't use it where HV will come into contact with it because it is a
> lousy insulator. Use plastics, ceramics, and other types of insulators and
> standoffs for the HV elements. As a matter of fact, wood can look as good
> as anything if finished properly. My pole pig powered coil uses wood for
> the structural parts such as decks and supports.
>
> For the tank circuit, my coil uses 3/8" copper tubing for everything:
> primary and connections. There is no "wire", so to speak. With my
> capacitors and pole transformer, JAVATC predicts that my tank circuit puts
> out about 450 amps for each discharge (240 bps). Due to the skin effect and
> high peak current I wanted to minimize my primary circuit losses, hence the
> 3/8" tubing for everything. Since your coil is NST powered, you don't have
> to go to that extreme. Just use some decent sized wire, say 12 AWG or
> larger. Smaller wire will also work, you will just have more losses
> although it may be hard to detect the difference. You will experience more
> heating with smaller wire. Just remember, due to the skin effect, the
> primary circuit current is only flowing in the outer millimeter or less of
> the wire. This is why thicker wire is more desirable even though the vast
> majority of the wire is not being used. This is also why copper tubing is
> best if you can make use of it.
>
> For HV wiring in the primary circuit connections, you can use use regular
> wire such as THHN slipped inside of clear vinyl tubing. The vinyl tubing
> provides a lot of insulation. You can look up the insulation standoff
> voltage for various thicknesses. Even with the tubing, I would still not
> let any of the HV wire come into contact with anything just as a
> precaution. Use standoffs made of insulating material such as ceramic, G10,
> etc. You can dispense with the clear plastic tubing if you can maintain
> adequate separation between the HV wiring. The vinyl tubing does provide
> some additional protection against corona losses.
>
> For the wiring from the NST to the primary circuit, you can use very small
> wire because the current is so low and the skin effect is negligible at 60
> Hz. My pole transformer powered coil uses Belden HV test lead which is only
> 22 AWG. I can do this because I am only pulling about 0.3 amps from the
> transformer. Since Belden HV test lead is expensive, you can just use
> regular wire if you take certain precautions. You can either suspend the
> regular wire away from the ground on standoffs or slip it inside some vinyl
> tubing for HV insulation. As before, the vinyl tubing will also supply
> additional protection against corona loss for regular wire.
>
> Here is what I did for my HV leads from the transformer to the primary
> circuit. As I stated earlier, I use 22 AWG Belden HV test lead rated at 10
> KVAC. Since this is below the 14.4 KV that my transformer puts out, I also
> slipped the test lead HV wire inside 1/2" vinyl tubing. These 2 combined
> gives me adequate insulation. I then enclosed the HV leads and vinyl tubing
> within a sheath of copper braid. I then ground the copper braid to earth.
> The copper braid serves 2 purposes. It absorbs any streamer strikes which
> may hit the leads and shunts them to ground. It also provides a more even
> charge distribution along the HV leads. So with this 3-part HV lead (Belden
> test lead, vinyl tubing, copper braid), I am confident to just let my HV
> leads just lie on the ground outdoors. This is probably a little extreme
> and you don't really have to do this for your NST coil.
>
> For primary circuit connections, I use mechanical connectors. I use a
> combination of store-bought connectors and custom-made connectors that I
> made myself.
>
>
>
> ----- Original Message -----
> From: "Daniel Kunkel" <dankunkel@xxxxxxxxx>
> To: "Tesla list" <tesla@xxxxxxxxxx>
> Sent: Tuesday, February 20, 2018 10:34:35 AM
> Subject: [TCML] General Construction Advice
>
> I am getting my second coil online after a 20 year hiatus and would like to
> do a decent job with the construction and build quality. I don't have the
> money or machine shop or 3D printer to make a beautiful/professional/museum
> quality display piece...but I don't want this thing to look like some
> amateur junk yard project either!
>
> So consider a moderately powered coil (15kv @60-120mA NST). Right now my
> chassis is made of wood with PVC legs to separate the levels. The primary
> coil support is a plastic cutting board. I'd like to keep the amount of
> metal in the chassis to a minimum, but it looks like I will be having to
> use screws and wood for general stand-offs, wire strain relief, and
> support. The primary coil and all wiring is 1/4" copper tubing.
>
> Here is a pic of current progress...my son helped me attach the casters!
> https://imgur.com/jL2ngVc
>
> Questions:
> What do you guys like to do for tank circuit wiring (including connecting
> the NST to the tank)?
> What kind of wire/tubing?
> What kind of insulation?
> What kind of electrical/mechanical connections (solder, nut&bolt)?
> What kind of insulator and stand-offs do you use?
>
> Thanks,
> ~Dan
> Kansas City area
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