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"LightningStorm" vacuum tube Tesla coil project

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LAN_403

Avenger

Thu Aug 04 2016, 02:43AM

Registered Member #1275 Joined: Wed Jan 30 2008, 09:33AM
Location: Russia, Kazan
Posts: 17

My last VTTC project. This project started one year ago, but only a month ago, the first sparks were obtained.
The objective of the project - to build a powerful vacuum tube Tesla coil on the basis of soviet metal-glass high-power air-cooled tetrode GU-39B-1. This tube is capable to dissipate at the plate power around 6kW. And its output power is 13kW.
It was made the plate and filament transformers. The filament transformer provides 6,6V and 100A. Plate transformer is wound on the base of the output transformer of the high power tube audio amplifier UPV-1,25 (russian Ð£ÐŸÐ’-1,25) used two GU-81M tube in push-pull output stage. Its core is made up of steel plates of thickness 0.35 mm (core sectional area of 49cm^2). It provides voltage 5kV and 2A peak Ñurrent (nominally 1,5Ð)
In the power supply used level shifter with eight 1uF 16KV capacitors and homemade diode pack at 50kV and 3a. All ceramic capacitors in circuit - soviet K15U-1 ("doorknob") or K15U-2 type.
The tube installed in a steel cylinder with polyamide insulator at the bottom. Centrifugal fan "bahcivan aorb" (BRDS 180-60, 1200 mÂ³/h) is used to cool the tube. Tube operates in triode.
The secondary winding contains 800 turns of 1mm copper wire on 160x800mm PVC pipe. Epoxy coating. 20x5cm aluminium toroid is installed.
The primary is a 35 turns of 4mm copper wire on 250x500mm PVC pipe. Taps on each turn, starting with the 28th turn. Winding height is 28cm. MMC capacity is 2nF (4x470pf).
Feedback winding has 14 turns of 1.5mm copper wire (taps of the first 5 turns). Located above the primary winding. Grid leak circuit is 200 Ohm and 14nF.
Tesla Coil working in staccato mode. In the cathode circuit installed triac, which is controlled by circuit in 555 timers (based of the staccato cotroller of Steve Ward).
At this moment VTTC gives streamers up to 1.5m length. The length of the streamers is limited to the power of the plate transformer and power mains capability (mains 230V 50Hz, current consumption up to 40A).

Video here: (work with triac)

And here: (work with thyratron TR1-5/2)

Mads Barnkob

Thu Aug 04 2016, 06:32AM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

Wow. You did a great and throurough job on this coil.

Windigns transformers, many bits and pieces home made, I really like it.

The sparks are beautiful, bit of a shame that the loud air cooling ruins the lovely sound of the sparks. CW mode is insane :)

I am wondering if you should try a larger topload to avoid so much near horizontal branching, was in the picture where sparks hit the tube heat connections :)

Would you mind sharing how you incorporated the thyratron tube as modulator?

Hydron

Thu Aug 04 2016, 12:20PM

Registered Member #30656 Joined: Tue Jul 30 2013, 02:40AM
Location: UK
Posts: 208

Very impressive!

Thanks for sharing the photos/videos of the coil.

Avenger

Thu Aug 04 2016, 03:32PM

Registered Member #1275 Joined: Wed Jan 30 2008, 09:33AM
Location: Russia, Kazan
Posts: 17

Thank you! But still a lot of work before the final realization of the project. Here is a photo of thyratron interrupter. It consists of a thyratron, the filament transformer (thyratron requires 5V and 15A), the bias power supply and IRFP450 MOSFET. The value of the negative bias on the grid of thyratron is about 24-30v. Interrupter works from my synchronous staccato controller unit (shown in photo).

Soviet mercury thyratrons TR1-5/2

And the video, where interrupter operates as a dimmer (use mains 230V and 300W bulb load):

Avenger

Thu Aug 04 2016, 03:36PM

Registered Member #1275 Joined: Wed Jan 30 2008, 09:33AM
Location: Russia, Kazan
Posts: 17

The circuit of the thyratron interrupter shown in the photo. Negative bias power supply and VTTC generator unit is not shown.

Patrick

Thu Aug 04 2016, 07:09PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

That glowing vacuum tube looks so cool.

Mads Barnkob

Fri Aug 05 2016, 06:40AM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

Thank you for all the extra information.

I have for many years, since I built my first VTTC in 2009, had a large QB5/2000 tube (2kW plate dissipation) and recently bought a TGI-700/25 thyratron tube(that however is mismatched with operating the QB5/2000), so your thread here sparked a little on getting on with the planning of that project :)

Dr. H.

Fri Aug 05 2016, 11:57AM

Registered Member #931 Joined: Mon Jul 30 2007, 05:25PM
Location: Bulgaria
Posts: 486

From a big tube lover - GREAT project

Just a question (not being smart or anything -really asking) - what is the advantage of using a thyratron over the simpler triac-staccato circuit ?

Well we can't argue wit the coolness factor.

Avenger

Fri Aug 05 2016, 09:18PM

Registered Member #1275 Joined: Wed Jan 30 2008, 09:33AM
Location: Russia, Kazan
Posts: 17

Dr. H. wrote ...

Just a question (not being smart or anything -really asking) - what is the advantage of using a thyratron over the simpler triac-staccato circuit ?

The advantage of using a thyratron is not found. So now I use TRIAC interrupter.

Mads Barnkob

Sat Aug 06 2016, 04:40PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

Avenger wrote ...

Dr. H. wrote ...

Just a question (not being smart or anything -really asking) - what is the advantage of using a thyratron over the simpler triac-staccato circuit ?

The advantage of using a thyratron is not found. So now I use TRIAC interrupter.

Differences between cathode modulation and anode modulation,

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