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1

Dual Resonant Solid State Tesla coils (DRSSTC) / Re: First DRSSTC SKM100

« on: April 15, 2024, 08:46:32 PM »

Temperature rise at 11 degree Celsius is border line to problems in longer runs without good forced air cooling.

I would place SKM100s around 400-600A depending on resonant frequency, do the loss calculations! https://kaizerpowerelectronics.dk/tesla-coils/drsstc-design-guide/igbts/ or scroll down to table of proved IGBT speeds/current.

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Dual Resonant Solid State Tesla coils (DRSSTC) / Re: mg75q2ys40 IGBT

« on: April 14, 2024, 07:20:54 AM »

Old, slow and not that high current rating. Becomes a challenge to drive fast enough for a small coil that has low current peaks, but as a result of being small, has high resonant frequency.

Calculate power dissipation to find out how hard you can drive it, I show how to do that here: https://kaizerpowerelectronics.dk/tesla-coils/drsstc-design-guide/igbts/

Older modules also have higher gate capacitances, making them harder to drive fast, check it https://kaizerpowerelectronics.dk/calculators/igbt-gate-drive-calculator/

Could I interest you in some 200A modules? https://ham.brugtgrej.dk/itemshow.php?obj=192531

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Dual Resonant Solid State Tesla coils (DRSSTC) / Re: IKY150N65EH7, is it good for DRSSTC

« on: April 14, 2024, 07:18:20 AM »

It might look good on paper, but if you do not consider your driving parameters and do the calculations, its only guesswork

Calculate power dissipation to find out how hard you can drive it, I show how to do that here: https://kaizerpowerelectronics.dk/tesla-coils/drsstc-design-guide/igbts/

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Beginners / Re: Tesla coil safety questions, risk analysis quantified

« on: April 10, 2024, 11:33:32 PM »

I usually refer to this Tesla Coil safety guide: https://www.pupman.com/safety.htm

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Dual Resonant Solid State Tesla coils (DRSSTC) / Re: Big Coil Big Sparks

« on: April 09, 2024, 07:34:19 PM »

Rough estimates would be to look at DRSSTC Tesla coils from Pythagoras, a^2 + b^2 = c^2, lets a and b be the same length/height as Tesla coil and maximum spark length is c. This seems to fit from table top coils to Lightning on demands 40 feet (13 meters) huge one https://www.youtube.com/watch?v=B7zuuoYJFmg .

Costs does however seem to rise squared to the size, so while costs are ^2, gain is only sqrt(2).

The Barnkob Pythagoras Tesla Coil Theorem

You want long sparks? How deep are your pockets?

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Dual Resonant Solid State Tesla coils (DRSSTC) / Re: Oversize Snubber Capacitor

« on: April 07, 2024, 07:49:29 PM »

Quote from: thedark on April 07, 2024, 06:28:12 PM

Quote from: Benbmw on April 07, 2024, 05:44:55 AM

However it is more likely to not be an issue unless you are over sizing by orders of magnitude

The snubber cap in a half bridge say 0.68uF and I only have a 1uf, It wouldn't have much of a problem would it?

Or it posibble make a MMC for a snubber?

1uF or 0.68uF, as a voltage splitter or DC blocking capacitor, will not make much of a difference.

Being in series with the primary coil, this is not a pure snubber capacitor. More like a DC blocking capacitor and to understand how to size such a thing, check this out: https://kaizerpowerelectronics.dk/tesla-coils/sstc-design-guide/

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Spark Gap Tesla Coils (SGTC) / Energy Museum Shut Down! Finn Hammers Tesla coil from 2003

« on: April 03, 2024, 05:08:29 PM »

I visited the Danish Electricity Museum back in Autumn 2023 and by pure coincidence it was their last opened weekend of the year and they would pack down to close for good, due to lack of funding.

Finn Hammer from www.hammertone.com built their Tesla coil back in 2003. I got to film its last ever public show, as an re-opening of the museum, might not be what it was originally when it closed.

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Dual Resonant Solid State Tesla coils (DRSSTC) / Re: Plasma Torid - Class E Self Resonant Dual/Stereo - Plasma Torid Build

« on: April 02, 2024, 09:27:21 PM »

Very thorough approach to your project and kudos for sharing everything

The build up with references is as much documentation as tribute is heartwarming.

If HVF had a award for Most Well-structured Thread, this is looking like a winner!

Looking forward to follow your project.

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Spark Gap Tesla Coils (SGTC) / Re: design Capacitor tank

« on: April 02, 2024, 07:40:51 PM »

It sounds like you are searching for the term "Larger Than Resonant" or LTR, when designing a MMC for a SGTC that does NOT resonate with the impedance of your NST, as this will destroy your NST. So try to look into that term and there should be plenty of information to find on google searches.

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Vacuum Tube Tesla Coils (VTTC) / Re: Kaizer VTTC 1

« on: March 29, 2024, 10:23:02 AM »

Thank you Steve

It is definitely worth making new videos, just look at the difference between my original 800x600 recordings, sitting on top of my new 4k recording. I had to add a red frame to emphasize how small that really is!

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Beginners / Re: Capacitor in Parallel with Primary Coil

« on: March 29, 2024, 10:17:34 AM »

It is called a tuned circuit, a resonant LC circuit or a tank circuit, many different names for the properties of pumping energy into a self-oscillating LC circuit.

You do need something to transfer that energy to, so a secondary tuned circuit, with a different LC ratio needs to be added. This is how a DRSSTC Tesla coil works.

A induction heater / stove / cooker works without a secondary LC circuit, that is purely a pan load (which represents some complex load) that gets the energy transferred.

Resonant circuits can ring up to very high currents, as you discovered, so you can transfer a lot of energy with short on-times.

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Electronic Circuits / Re: Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!

« on: March 25, 2024, 07:41:29 PM »

You're right, it is a mix of water and glycol. I assumed it was oil, as it was very slippery and not at all sticky. The also explains the sweet vanilla taste and reminding me of the olds days in the 90s in the discos. I guess it was partly used to combat the smell of cigaret smoke.

https://protectglobal.com/products/fluid-containers/protect-foqus-600i-1100i-fluid-container/

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Electronic Circuits / Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!

« on: March 22, 2024, 10:20:35 PM »

I found a old and discarded smoke cannon at a scrap yard! It looked in rough shape, but still had some oil in its container. With a bit experimentation and at last forcefully feeding it oil, it gave off its smoke!

As a bonus, I got most of my workshop lubricated from half-burned oil smoke raining down droplets everywhere!

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Sell / Buy / Trade / Re: [WTS] IGBT, Ferrite, Capacitors, Tools, PSU, Industrial components and parts

« on: March 21, 2024, 01:37:32 PM »

Added new items, 48 items for sale now.

Added heat sinks and various industrial parts.

https://ham.brugtgrej.dk/itemlist.php?mode=useritems&userid=2620

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Transformer (Ferrite Core) / Re: Difference between these transformers

« on: March 20, 2024, 08:03:41 PM »

Flyback transformers are special in having an air gapped core, which is utilized by the driving method Flyback converter topology.

So a flyback transformer is just a air gapped transformer. It is the driving method where energy is stored in the core in the first half cycle, switch turns off and energy is transferred to the secondary winding in the second half cycle.

The term flyback comes from Cathode ray tubes (old TVs and monitors) where the abrubt saw tooth like output, got the beam in the cannon to flyback to draw the next line on the monitor.

In high voltage world, we abuse the shit out of them with all other kinds of drive modes than flyback

We feed them with ZVS, single switch, half-bridge or full-bridge inverters to get the highest possible voltage output, often leading to a premature death of the transformer.

To drive it continuesly, the air gap should be removed, as the half cycle energy storage is no longer being used. On the other side, core saturation will happen much faster.

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General Chat / Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?

« on: March 20, 2024, 07:51:57 PM »

Being a inverter, rather than a big lump of iron, a microwave inverter is not as sturdy and can stand up to abuse.

Look up the load impedance of a magnetron and you got an idea of how much you load the output. They are most likely only rated for full power for a 5-10 minutes, with forced air cooling.

All that being said, it is a nice small 2300 VAC inverter, on/off controlled, maybe something like power supply for a marx generator.

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Dual Resonant Solid State Tesla coils (DRSSTC) / Re: Benjamin's DRSSTC 2 in progress

« on: March 20, 2024, 10:39:47 AM »

Quote from: Benjamin Lockhart on March 19, 2024, 11:12:24 PM

Thanks Mads, I thought that a 100A rectifier would be ok for a coil running off a 50A breaker?
I have a single phase 240V supply so the bus voltage should be 680V with no load.

There is some derating graphs in the datasheet. Here both sine wave and rectangular are mentioned, where the rectangular causes higher dissipation etc.

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General Chat / Re: Welcome new members, come say hello and tell a little about yourself :)

« on: March 19, 2024, 05:01:41 PM »

As always, it is great to see more people join the HVF community! Young, old, experienced, new learners and great to see the eager to build and share

Thanks for taking the time to give an introduction of yourselves

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Dual Resonant Solid State Tesla coils (DRSSTC) / Re: Benjamin's DRSSTC 2 in progress

« on: March 19, 2024, 04:31:02 PM »

Beautiful work on that bridge, I love to see some nice handmade items

I never tried split MMC, so looking forward to hear more about your experience in that field.

I think your poor little half-bridge rectifier SKKD 100/12, is going to suffer a bit, you might need a bigger one. Surge overload current capabilities is however helped with a much lower Vrrm voltage, as you are properly at 500-600VDC?

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Dual Resonant Solid State Tesla coils (DRSSTC) / Re: 160mm DRSSTC II project | Questions

« on: March 19, 2024, 03:59:54 PM »

Quote from: Late on March 18, 2024, 02:59:46 PM

I have decided to make some small changes to my coil design. I've decided to use 10mm copper pipe for the secondary with 8mm spacing between turns. This should allow the primary to keep cooler during longer runs without the need of water-cooling the primary. Recalculating with java TC i get a coupling coefficient from 0.14 to 0.17 depending on how high the primary is. Which brings me to my first question. What's the optimal coupling coefficient for DRSSTCs of this size and power? And how high coupling coefficient is too high for a DRSSTC? Looking at other builds on this forum ive seen coils with a range of coupling coefficient from around 0.1 to even i think 0.2. From what I've read the higher the coupling coefficient is the more power can be transferred from primary to secondary but at the risk of having racing sparks. That's why I'm wondering about the optimal coupling to get the max spark length without increasing the risk of racing sparks too much.

Second question i have is about my secondary coil. Originally i planned to use 0.355mm wire and have the winding length of around 730mm with 2000 turns, Calculating this gives me spacing between turns of 0.01mm. How realistic is it to wind it that tight? And would it be better to get 0.315mm copper wire instead of 0.355mm in order to achieve the 2000 turns and having close to 730mm of winding?

Last but not least ive started to plan out the laminated bus design for my coil. I plan to make it from 2mm alu sheet with 2mm of fiberglass material as the insulating layer.

How does the current layout look in terms of good design practices and keeping the inductance low? Is there anything i should improve in the layout or the overall DRSSTC design?

1) 0.15 to 0.2 is normal for coupling of a DRSSTC, is does not have the same high voltage primary as a SGTC, which JavaTC is designed for, so suggested coupling should be a bit higher for DRSSTC.

2) Enamel thickness on a thin wire is roughly adding around 10% to diameter, so what I input to my helical coil calculator ( https://kaizerpowerelectronics.dk/calculators/helical-coil-calculator/ ) to get winding length for JavaTC with a wire size of 0.355 mm would be 0.0355 mm between turns (1 layer from each wire). You could also check out the manufacturers specification of enamel thickness, I got a table of thickness depending on the wire classes here: https://kaizerpowerelectronics.dk/tesla-coils/drsstc-design-guide/secondary-coil/

3) Your laminated bus is about as low inductance as you can get. Only thing would be to move rectifier to the side, so have shorter path from +/- to the capacitors, instead of going over one of the IGBTs, placing it in the middle would make it even for everybody. Properly a totally neglectable detail.

Messages - Mads Barnkob

Dual Resonant Solid State Tesla coils (DRSSTC) / Re: First DRSSTC SKM100

Dual Resonant Solid State Tesla coils (DRSSTC) / Re: mg75q2ys40 IGBT

Dual Resonant Solid State Tesla coils (DRSSTC) / Re: IKY150N65EH7, is it good for DRSSTC

Beginners / Re: Tesla coil safety questions, risk analysis quantified

Dual Resonant Solid State Tesla coils (DRSSTC) / Re: Big Coil Big Sparks

Dual Resonant Solid State Tesla coils (DRSSTC) / Re: Oversize Snubber Capacitor

Spark Gap Tesla Coils (SGTC) / Energy Museum Shut Down! Finn Hammers Tesla coil from 2003

Dual Resonant Solid State Tesla coils (DRSSTC) / Re: Plasma Torid - Class E Self Resonant Dual/Stereo - Plasma Torid Build

Spark Gap Tesla Coils (SGTC) / Re: design Capacitor tank

Vacuum Tube Tesla Coils (VTTC) / Re: Kaizer VTTC 1

Beginners / Re: Capacitor in Parallel with Primary Coil

Electronic Circuits / Re: Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!

Electronic Circuits / Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!

Sell / Buy / Trade / Re: [WTS] IGBT, Ferrite, Capacitors, Tools, PSU, Industrial components and parts

Transformer (Ferrite Core) / Re: Difference between these transformers

General Chat / Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?

Dual Resonant Solid State Tesla coils (DRSSTC) / Re: Benjamin's DRSSTC 2 in progress

General Chat / Re: Welcome new members, come say hello and tell a little about yourself :)

Dual Resonant Solid State Tesla coils (DRSSTC) / Re: Benjamin's DRSSTC 2 in progress

Dual Resonant Solid State Tesla coils (DRSSTC) / Re: 160mm DRSSTC II project | Questions

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