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Re: Seibt Photo

Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>

Hi Kurt,

Thanks for the data.
Question: Was there an electrical or mechanical reason for the toroidal primary?

I like the height of the coil for demonstration. I'll use what I already have here at home. Thus, I think I'll be using a using a 2" x 80" pvc with a 70" winding length. I'll end up around 3100 turns if I use the 24awg I have here. This will put me at about 382kHz. A helical driver coil should suffice connected in the simple autotransformer setup. I want to keep it simple and this is the reason for the toroidal primary question above.

Take care,
Bart B.



Tesla list wrote:

Original poster: Kurt Schraner <k.schraner@xxxxxxxxxxx>

Hi Bart,

Thanks :-). To build one is indeed easy for an experienced coiler! Making an internet page of it, certainly is a good idea, and I will consider it. I've just a small practical problem, because my free webspace is almost full, and I must clean / reorganize / strip my website from no more needed obsolete details...
But here are some data of my Seibt, as currently operated:

Seibt Resonator:
- PVC tube of diameter = 4cm, total length = 200cm
- Winding length = 150.3cm, wire dia.=0.319mm(0.35mm insul.) -> AWG28
  (Number of turns counted = 4187)
- Corona wire, 0.5mm dia. brass, hold by two 5mm dia. brass bars.
  (Length of the bars = 20cm, but 14cm would suffice)
- Low f inductance 18.21mH (experimental and calc.)
- 1/4 wave resonance 366kHz (experimental, without corona wires)
- 1/4 wave resonance~280kHz (exper., corona wires @ 2.5cm from coil)

Helical Primary:
- PVC tube of dia.= 12.5cm, total length = 34cm
- Winding length = ~23cm, wire dia.=3.5mm (solid copper) -> ~AWG8
  (Number of turns 19, spacewound with pitch = 12mm).
- Low f inductance 21.4uH (experimental)  and 21.3uH (calc.)

Primary Cap:
- 2 seriesed Leydenjars C = 474pF (high loss -> corona!)
- An exchange of the Leydenjars by doorkoms of similar capacitance
  didn't show an easily visible effect.

Static Sparkgap:
- 2cm dia. zinc-halfspheres, spark-distance ~2cm

Please see also again:
http://home.datacomm.ch/k.schraner/Seibt_schema_3.gif

The problematic element, when planning to build this Seibt, may be the power supply, in form of an induction coil. My induction coil draws 250VA up to 350VA in this application, and easily sparks 12cm. More could be said about it. But it may be worth, alternatively to try a NST-based supply. In that case, instead of my autotransformer-primary, probably a maggie-style driver would work better. (The Seibt seems to "love" beeing fed with fairly high voltage).

Instead of letting the Seibt open circuit at the top, it's also feasible to connect the top to the top end of the corona frame, forcing a voltage node -> current maximum at this place. Different excitation resonance modes are possible that way, when getting the same strength of corona zone display. A single wire along the coil is also sufficient to give good corona.

Best regards,
               Kurt


Tesla list schrieb:

Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>
Hi Kurt,
I was equally impressed with your picture. I'd love to build one myself. I was completely unaware of the Seibt coil until you mentioned it here on the list. If you get the urge (or maybe you already have and I didn't pay attention), I'd love to read a "how to" sometime. Maybe you could point to an internet source or write up one of your own?
Excellent work!
Bart B.