Author Topic: Small VTTC project, PL500 based  (Read 141 times)

Offline tefatronix

  • High Voltage Enthusiast
  • *
  • Posts: 7
  • Karma: +0/-0
    • View Profile
Small VTTC project, PL500 based
« on: January 02, 2020, 01:14:38 AM »
Hello. Here is my small VTTC project based on the PL500 tube. I have built a few SSTCs and played with VTTCs before, but this is the first VTTC I finished and properly documented.

The Tesla coil runs directly from 230 V~ mains through a voltage doubler. It consumes 15-16 watts idle (filament only) or 40-80 watts depending on the power level set. The sparks are ~4 cm long. The secondary coil is about 8 cm tall, 3.2 cm thick and resonates at ~2.4 MHz.

Here is the schematic diagram:


It is a classic Class C  Armstrong-style oscillator.  Both L1 and L2 are wound on a 5 cm diameter PP pipe. L1 has 15 turns with several taps between turns 10 and 15. L2 has about 8 turns. C8 is built from three WIMA FKP1 1 nF/2 kV= capacitors in series (333 pF, 6 kV). Another 33 pF 3 kV capacitor is connected in parallel, giving a total capacitance around 370 pF.  I used a 13 V transformer with a voltage doubler (measured voltage 26-28 V with load) as I didn't have a proper reasonably sized 27 volt transformer.

The MOSFET circuit regulates the power. It's regulated by (dis)connecting the cathode. The mains voltage is half-wave rectified by D1. R5, R6, RV1 form an adjustable divider. If the voltage on the output of this divider gets high enough, neon lamps X1, X2 (strike voltage around 80 V per lamp) turn on and their voltage drop decreases, increasing G-S voltage of Q1, turning it on. If the voltage on the divider output drops, the lamps turn off and Q1 also turns off. This limits the operating duty cycle, decreasing heating while maintaining spark length.

Here is the entire device:


It is mounted on a pertinax (phenolic resin filled, I think) board. The circuit board is uncovered (a bit of a safety hazard). The PCB was designed and laid out by hand with an etch-resistant marker, as I was too lazy to make KiCad footprints for several parts that weren't there.

And here it's operating:


Bigger sparks could probably be achieved with a more powerful (PL504) or less worn tube, but it works OK.  Hopefully I'll get hold of some 6P45S or PL509 tubes for my next VTTC project (maybe) to be able to push the power higher without damaging the tube.
Video link: https://www.youtube.com/watch?v=BtGX9NkrPT8[/attachment]
« Last Edit: January 02, 2020, 09:57:00 AM by tefatronix »
Website with documentation for my DIY projects (high voltage, low voltage etc.): http://tefatronix.g6.cz/

Offline Mads Barnkob

  • Administrator
  • High Voltage Expert
  • *****
  • Posts: 1236
  • Karma: +17/-0
  • Denmark
    • View Profile
    • Kaizer Power Electronics
Re: Small VTTC project, PL500 based
« Reply #1 on: January 02, 2020, 02:48:36 PM »
Nice little coil, all fitting on a small board.

VTTC sparks are just something special.

What is the reason for making a MOSFET/Neon bulb interrupter compared to the "standard" staccato controller that almost everyone uses for their VTTCs to drive a SCR/TRIAC?

I made a PL36 junk VTTC once, poor little thing got abused and could only do short runs with serious red plating :) Was also doing CW. Schematic and such can be found here: http://kaizerpowerelectronics.dk/tesla-coils/kaizer-vttc-iii/

http://www.kaizerpowerelectronics.dk - Tesla coils, high voltage, pulse power, audio and general electronics

Offline tefatronix

  • High Voltage Enthusiast
  • *
  • Posts: 7
  • Karma: +0/-0
    • View Profile
Re: Small VTTC project, PL500 based
« Reply #2 on: January 03, 2020, 11:30:12 AM »

Thanks, Mads! There is no particular reason why I used the MOSFET circuit, except the simplicity and the fact that I just quickly put it together during the original tests and kept it, I think it could be replaced with a SCR with very minor changes. I wanted it to work more as a phase cut regulator than a regular staccato circuit.


This way I also get it to turn off before the actual half cycle ends, but I doubt it plays any role... I just had those parts on the work table from previous experiments and wanted to see how such a circuit would work.


Wow, that tube got hot quickly in that video. I also got some red plating here after longer CW runs without the regulator circuit.
Website with documentation for my DIY projects (high voltage, low voltage etc.): http://tefatronix.g6.cz/

High Voltage Forum

Re: Small VTTC project, PL500 based
« Reply #2 on: January 03, 2020, 11:30:12 AM »

 


* Recent Topics and Posts

post Re: GM tube hv transformer
[Detection, Counting and Measurements]
futurist
January 25, 2020, 11:01:24 AM
post Re: CT performance investigations (Pearson and DIY)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
T3sl4co1l
January 25, 2020, 06:44:21 AM
post Re: Mazilli ZVS Driver Modification Problems
[Transformer (Ferrite Core)]
T3sl4co1l
January 25, 2020, 06:37:47 AM
post Re: Mazilli ZVS Driver Modification Problems
[Transformer (Ferrite Core)]
Andrew321
January 25, 2020, 02:22:09 AM
post Re: GM tube hv transformer
[Detection, Counting and Measurements]
haversin
January 25, 2020, 01:15:21 AM
post Re: GM tube hv transformer
[Detection, Counting and Measurements]
klugesmith
January 24, 2020, 10:53:42 PM
post Re: WTB [EU]: Cellular Sector Antenna
[Sell / Buy / Trade]
Da_Stier
January 24, 2020, 10:52:48 PM
post Re: GM tube hv transformer
[Detection, Counting and Measurements]
haversin
January 24, 2020, 10:29:14 PM
post Re: Problems with my first DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
bozidar
January 24, 2020, 08:16:12 PM
post GM tube hv transformer
[Detection, Counting and Measurements]
AlexanderHun
January 24, 2020, 06:24:25 PM
post Re: DIY SMAW welder (stick welding)
[Electronic Circuits]
rikkitikkitavi
January 24, 2020, 05:17:01 PM
post Re: My 833A VTTC
[Vacuum Tube Tesla Coils (VTTC)]
MRMILSTAR
January 24, 2020, 04:37:25 PM
post Re: simple confusion about UD2.7c LEDs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
justin66
January 24, 2020, 04:15:41 PM
post Re: My 833A VTTC
[Vacuum Tube Tesla Coils (VTTC)]
Mads Barnkob
January 24, 2020, 01:15:46 PM
post Re: simple confusion about UD2.7c LEDs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
January 24, 2020, 01:10:38 PM
post Re: simple confusion about UD2.7c LEDs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hydron
January 24, 2020, 12:39:01 PM
post Re: simple confusion about UD2.7c LEDs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
justin66
January 24, 2020, 11:43:08 AM
post Re: My 833A VTTC
[Vacuum Tube Tesla Coils (VTTC)]
kilovolt
January 24, 2020, 11:10:55 AM
post Re: DIY SMAW welder (stick welding)
[Electronic Circuits]
kamelryttarn
January 24, 2020, 10:11:51 AM
post Re: Doorknob vs Ceramic Disk
[Voltage Multipliers]
kilovolt
January 24, 2020, 09:03:52 AM
post Re: CT performance investigations (Pearson and DIY)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hydron
January 23, 2020, 11:50:22 PM
post Re: simple confusion about UD2.7c LEDs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
January 23, 2020, 11:42:56 PM
post Re: WTB [EU]: Cellular Sector Antenna
[Sell / Buy / Trade]
Mads Barnkob
January 23, 2020, 11:35:07 PM
post Re: simple confusion about UD2.7c LEDs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
justin66
January 23, 2020, 11:15:12 PM
post Re: Doorknob vs Ceramic Disk
[Voltage Multipliers]
MRMILSTAR
January 23, 2020, 10:42:22 PM
post Re: CT performance investigations (Pearson and DIY)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
T3sl4co1l
January 23, 2020, 10:03:17 PM
post Re: Doorknob vs Ceramic Disk
[Voltage Multipliers]
kilovolt
January 23, 2020, 09:55:05 PM
post Re: Doorknob vs Ceramic Disk
[Voltage Multipliers]
MRMILSTAR
January 23, 2020, 08:39:10 PM
post Re: Universal bus precharge & fan speed controller
[Dual Resonant Solid State Tesla coils (DRSSTC)]
acobaugh
January 23, 2020, 08:37:43 PM
post Re: simple confusion about UD2.7c LEDs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
acobaugh
January 23, 2020, 08:16:02 PM
post simple confusion about UD2.7c LEDs
[Dual Resonant Solid State Tesla coils (DRSSTC)]
justin66
January 23, 2020, 07:48:39 PM
post Re: Bipolar high voltage multiplier project - more than 70cm hot arc discharge
[Voltage Multipliers]
kilovolt
January 23, 2020, 05:07:46 PM
post Re: My 240kv voltage multiplier
[Voltage Multipliers]
kilovolt
January 23, 2020, 05:05:40 PM
post Re: Doorknob vs Ceramic Disk
[Voltage Multipliers]
kilovolt
January 23, 2020, 05:01:27 PM
post WTB [EU]: Cellular Sector Antenna
[Sell / Buy / Trade]
Da_Stier
January 23, 2020, 04:34:34 PM
post Re: My X-Ray Machine
[X-ray]
Agent Smith
January 23, 2020, 03:47:06 PM
post Re: DIY SMAW welder (stick welding)
[Electronic Circuits]
rikkitikkitavi
January 23, 2020, 02:24:07 PM
post Re: DIY SMAW welder (stick welding)
[Electronic Circuits]
kamelryttarn
January 23, 2020, 01:29:01 PM
post Re: DIY SMAW welder (stick welding)
[Electronic Circuits]
rikkitikkitavi
January 23, 2020, 12:45:40 PM
post Re: DIY SMAW welder (stick welding)
[Electronic Circuits]
kamelryttarn
January 23, 2020, 11:38:18 AM
post Re: DIY SMAW welder (stick welding)
[Electronic Circuits]
rikkitikkitavi
January 23, 2020, 10:43:36 AM
post DIY SMAW welder (stick welding)
[Electronic Circuits]
kamelryttarn
January 23, 2020, 08:32:56 AM
post Re: Doorknob vs Ceramic Disk
[Voltage Multipliers]
davekni
January 23, 2020, 06:06:20 AM
post Re: Mazilli ZVS Driver Modification Problems
[Transformer (Ferrite Core)]
davekni
January 23, 2020, 05:57:18 AM
post Doorknob vs Ceramic Disk
[Voltage Multipliers]
Andrew321
January 23, 2020, 03:57:09 AM
post Re: CT performance investigations (Pearson and DIY)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hydron
January 23, 2020, 12:33:44 AM
post Re: CT performance investigations (Pearson and DIY)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
T3sl4co1l
January 22, 2020, 11:45:26 PM
post Re: CT performance investigations (Pearson and DIY)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hydron
January 22, 2020, 11:30:26 PM
post Small DIY plasma globe using ZVS oscillator
[Transformer (Ferrite Core)]
davekni
January 22, 2020, 06:21:31 AM
post Re: Mazilli ZVS Driver Modification Problems
[Transformer (Ferrite Core)]
Andrew321
January 22, 2020, 05:54:17 AM

Sitemap 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
SimplePortal 2.3.6 © 2008-2014, SimplePortal