Author Topic: help! GU-81M VTTC appears to be jumping between poles  (Read 570 times)

Offline Continuum

  • High Voltage Enthusiast
  • *
  • Posts: 7
  • Karma: +0/-0
    • View Profile
help! GU-81M VTTC appears to be jumping between poles
« on: June 21, 2024, 01:34:05 AM »
Hello!
This is my second post regarding this coil, the previous one being https://highvoltageforum.net/index.php?topic=1212.0

Below i attach the current schematic of the system that i laid out in KiCad. A .png and a .pdf for more pleasant viewing, choose which you prefer :)
* vttc-gu-81m.pdf


Anyway, this build certainly was a bumpy ride. I have made many mistakes in the design, and unaware of them i managed to somehow make the coil run a couple of times, still having a world of trouble with it. Here are some of the milestones:
-first, i ran the coil on its second or third resonant mode unaware of it. this appears to have contributed a load to terrible issues with flashovers from the primary, that caused me to abandon the project for a couple of years. i believe that running the coil at these higher modes caused the voltage to have many maximums across the lenght of the coil, thus attracting trouble.
-second, of course the coupling was also way up there, making issues with flashovers from the primary even more frequent.

After figuring these out, the system operates quite nicely, giving me an output of 50-55 cm with some sparks hitting up to 60+cm (longest recorded was 63 cm). a video proof from my most recent run :p https://youtube.com/shorts/ZtRdq05JS9Y
in the video i slowly ramp the power up with my variac and once im done you can hear me say "pełna moc" - "full power" in polish. you can see the tube red-plating later on, and the sparks growing in size slowly even after i have turned the voltage up all the way already. More on this odd phenomenon below.




The design has two features not so often seen in tube coils: a separate screen grid supply - 600V on full blast - courtesy of Jakub Tejiščák and his VTTC X, and a variable grid leak with 5 different resistances availble as follows, 510 Ohms, 1k8 Ohms, 4k7 Ohms, 7k5 Ohms and 22k Ohms. The gridleak cap is 2.2n.
Also, the secondary has been made with a low resonant frequency of around 100 kHz in mind as i wanted those nice branchy sparks that VTTCs are known for when operating below ~200 kHz.

Here are the current specs:
2 mots in parallel with a doubler, 32uF in the doubler circuit (oh yeah, i scored this huge capacitor and immediately knew i had to put it in the doubler)
a filter consisting of some nice dorknoob caps 2n 20kv, a bunch of microwave oven caps, and two coils i wound on a ferrite core from a tv flyback transformer. the B+ is also later 'decoupled' with three 47n caps closer to the resonator. For the layout please refer to the attached schematic and pictures.




The system has been split into three floors.
1-st lowest floor is the power supply. to the side is the low voltage wiring, and with appropirate spacing the rest of this floor is taken up by the rather beefy B+ supply.
2-nd floor is the tube floor. here lives the tube, the filament transformer, the screen grid supply, and the grid leak.
3-rd floor is the resonator floor. here live the resonant caps, and the aforementioned 3x47n caps that help keep the B+ stable, and of course all the coils.

The secondary is wound on a 100 mm diameter tube with a 0.2 mm magnet wire, 2000 turns, lenght of winding about 450 mm.
The primary is about 45 turns of 2.5 mm2 wire with taps from the 30-th turn on a 160 mm diameter tube, lenght of winding around 130-140 mm.
The feedback coil is about 25 turns of 0.6 mm wire with taps from the 11-th turn on a 160 mm diameter tube.
The toroid has a 190 mm major diameter and a 60 mm minor diameter.
The resonant cap consists of four 2200 pF 10 kV ceramic HF caps in parallel.

Measurements of the coils (separated):
secondary f0 unloaded = 141 kHz
secondary f0 loaded with a 630 mm brass tube simulating a long discharge = 120 kHz
Primary has thus been tuned to 120kHz.
After coupling the resonators, the poles are as follows (secondary still loaded with the simulated streamer):
f1 = 108 kHz
f2 = 142 kHz
These suggest a coupling factor k of about 0.25.

Now, im still debating on further increasing the diameter of the primary up to a 200mm diameter tube, which hopefully would enable me to slide it up a bit higher so it overlaps with more of the secondary. that is without a flashover of course, because currently i feel like im very close to one and the primary and feedback coils are slid down as low as they go. The secondary starts about 100mm above the 3-rd floor. Im hesitating to do this mod though as i think it might have a large negative impact on streamer lenght. ill probably test it soon and see.
And of course a staccatto circuit will be added shortly :)

A pecuilar behaviour of the circuit is that slowly, despite the input voltage being constant, the spark lenght grows over time. Together with that, the anode slowly turns red. I also notice that the average screen grid current can increase even two or three fold over the course or a minute or so! from a nice and comfy 100mA, up to even 300 mA if i really let it roll. This certainly does not make me feel at ease letting the coil run for longer than a minute, as the maximum screen grid dissipation of 120 W could easily be doubled this way. Why is that? i believe this could be a thermal runaway condition, but what starts it? i even measured the peak control grid voltage and current, and it remains under 150V and 80mA at full power. Thats still a little bit more than the max 10 W rating of this grid, but since these are peak mesurements i figure it souldnt cause a thermal runaway so soon? Is this maybe a normal behaviour for a red-plating tube?

All the peak values i measure with a simple passive peak detector and an analog meter. The currents are measured over the shunt resistors shown in the schematic (22 Ohms).

Here comes another troublesome bit.
Seeing how nice the system drives a ~100kHz coil i wanted to see how it would do with a far higher resonance. I wound another secondary coil on a 100 mm diameter tube with 1 mm wire, around 400 turns and 420 mm in lenght. For the resonant cap i use 15 kV 100 pF vacuum caps, two or three in parallel. Two seem to have given me the best results. Everything else in the setup remains unchanged.
Here are the measurements i took of the resonators. first i measure the secondary with the primary disconnected, and then i measure the primary with the secondary ungrounded (i found that upon ungrounding it, the effect of removing the secondary was not noticeable compared to leaving it in.). I tuned the primary to the frequency of the secondary loaded with an optimistic 630 mm simulated streamer.
secondary f0 unloaded = 757 kHz
secondary f0 loaded with a 630 mm brass tube simulating a long discharge = 641 kHz
Primary has thus been tuned to 640 kHz.
After coupling the resonators, the poles are as follows (secondary still loaded with the simulated streamer):
f1 = 541 kHz
f2 = 787 kHz
These suggest a coupling factor k of about 0.403.

Tuning the coil to 640 kHz i get the coil to operate at one frequency, no jumping around the poles. very little output up to about 100 VAC on the primary of the HV supply, and if i go any higher, the tube flashes over internally so i quit testing it above 100 VAC. I see no excessive voltage induced on any of the leads, i test this simply by poking all the terminals with a chicken stick with a piece of metal on its end. When i see a spark, i know somethings up. Of course this is by no means a good measurment, but still I am surprised, as with the 100 kHz coil at full power i can draw small arcs from the primary taps (3 mm) and i see a tiny spark whenever i touch anything metal, and yet the tube seems to be alright, and here, basically no sparks and the tube flashes over?
i have a 150 V voltmeter with a peak detector that i could use to measure the control grid voltage with, as its the only real unknown. The average screen grid current remains in line (about 50 mA at 100 VAC in). Of course the screen voltage is at that point about 200 V peak as it is supplied by a doubler from a 1:1 transformer supplied from the same voltage that the B+ supply is.
If i tune the primary higher (for example to the f0 of the unloaded coil, 757 kHz) the radiated frequency i monitor with my scope changes with every mains cycle. it can even switch mid way through the cycle. I see the driver jumping between the poles, one (the higher pole) giving significantly more output than the lower one.
My luckiest run so far i have tuned the primary coil so the higher pole was about 800kHz, and with such tuning the sparks would suddenly begin when the supply voltage reached 150 VAC. Even 130 VAC would yield very little sparks, but after crossing the 150 VAC line, they coil would begin producing nice, 250 mm sword-like sparks. Here is video evidence https://youtube.com/shorts/qLLtH38y0Yk (i speak a little in my native language here, transcription in the description of the video.) Has anyone had a similar case? i havent seen it discussed anywhere and im at a bit of a loss, not sure what to do to make the coil operate and not hurt the tube! Any ideas?

So to restate my questions:
-with the 100 kHz coil - why do the sparks grow with constant B+ voltage, along with the grid current, and the anode getting red?
-with the ~800 kHz coil - why does my driver jump around the poles so much, why does the higher pole produce much better output, and why does my poor tube keep flashing over when i tune to the lower pole, despite not much happening at all?

sorry for the lenghty post, but i wanted to include all the relevant technical details so all of you who decide to read this chunk of text can learn as much about this system as possible. Id be very thankful for your replies and suggestions, and if you have any questions, please post them below and ill get back to you soon.
PS im afraid the attachments havent loaded correctly, if that is so i shall follow this post up with a comment containing all the missing files. lets hope it works first try.

Offline davekni

  • Executive Board Member
  • *******
  • Posts: 2859
  • Karma: +134/-2
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: help! GU-81M VTTC appears to be jumping between poles
« Reply #1 on: June 21, 2024, 03:20:33 AM »
Quote
-with the ~800 kHz coil - why does my driver jump around the poles so much, why does the higher pole produce much better output
I have no experience with VTTCs, so have no particularly useful advice.  One detail from IGBT DRSSTCs might be relevant.  Typical DRSSTCs switch from lower pole to upper pole as arc loading reduces secondary resonant frequency below primary resonant frequency.  (Referring to isolated uncoupled frequencies.)  My work-in-progress ZVS oscillator driven DRSSTCs does the same thing.  However, no improvement in arc size at upper pole, often the opposite.

Hope you get some help from others with real experience.
« Last Edit: June 21, 2024, 03:22:21 AM by davekni »
David Knierim

Offline Continuum

  • High Voltage Enthusiast
  • *
  • Posts: 7
  • Karma: +0/-0
    • View Profile
Re: help! GU-81M VTTC appears to be jumping between poles
« Reply #2 on: June 21, 2024, 09:26:07 AM »
Thank you for the reply!
Typical DRSSTCs switch from lower pole to upper pole as arc loading reduces secondary resonant frequency below primary resonant frequency.  (Referring to isolated uncoupled frequencies.)
Ive been reading some other threads about DRSSTCs here and ive read that tuning the primary below the lowest frequency of the secondary - loaded with a large streamer - helps keep the driver from juming around. i also implemented this here by tuning to 640 kHz, and it indeed stopped the spontaneous frequency hopping, but i still get an overvoltage condition on my tube. significant enough to cause it to flash over, and thats something considering ive seen people run it on 8 kV. Anyway, I still struggle to understand why the driver would switch once the secondary uncoupled f0 frequency falls below primary uncoupled f0 frequency. As i understand it, in a DRSSTC the feedback is taken from the current at the bottom of the coil via a current transformer... In my VTTC its taken from the primary via the feedback coil positioned below the primary, but of course is also sensitive to the secondarys field. What mechanism causes these feedback systems to change the frequency of operation at this particular condition?

Oh and also, second thing. about my previous question
Quote
-with the 100 kHz coil - why do the sparks grow with constant B+ voltage, along with the grid current, and the anode getting red?
i know why i get the red plate of course... the tube is getting a workout with a B+ voltage more than the rated value. i havent measured it but unloaded the doubler gives about 6 kV peak, compared to the tubes rated 3 kV. Loading does of course pull it down so i expect 4-5 kV peak, which is still a bit much. Anyway i dont intend to run the coil for extended periods of time so i figure its okay to push the tube a little, ive also seen many other coilers power it with such a high voltage. But still, even red-plating, why do the grid currents grow 'by themselves' and why does the spark lenght grow? I suspect that with more grid current, we get more power out of the tube, hence spark growth - more plate current. But the grids? What exactly is happening here? Are they getting heated by the glowing anode, which pushes them into a thermal runaway? is this all normal for a red plating tube?

Offline Anders Mikkelsen

  • Global Moderator
  • High Voltage Experimenter
  • *****
  • Posts: 77
  • Karma: +9/-0
    • View Profile
Re: help! GU-81M VTTC appears to be jumping between poles
« Reply #3 on: June 21, 2024, 02:01:58 PM »
Quote
Tuning the coil to 640 kHz i get the coil to operate at one frequency, no jumping around the poles.

What do you mean by tuning the coil in this case?

As I understand it, you have two coils with a resonant frequency of 640 kHz and a coupling of .4, giving you a system with two resonant frequencies as you state. Between these two resonances, there is a minimum power transfer point, so you can't drive it at that frequency. To get any significant output you need to drive it at (or close to) either the upper or lower pole of the coupled resonators.

Having the primary and secondary tuned to the same frequency when uncoupled gives both poles the same gain. Detuning the primary shifts the power transfer at each pole. For self oscillating drivers, this allows you to select which pole to operate at by choosing which pole has the highest gain. Tuning the primary lower than the secondary will favor lower pole operation, but it's also possible to drive it at the upper pole, just difficult with self oscillating feedback.

Offline Continuum

  • High Voltage Enthusiast
  • *
  • Posts: 7
  • Karma: +0/-0
    • View Profile
Re: help! GU-81M VTTC appears to be jumping between poles
« Reply #4 on: June 22, 2024, 12:25:10 AM »
Thank you for the reply!
Quote
What do you mean by tuning the coil in this case?
I mean tuning it decoupled from the other coil. The primarys measured f0 was 640 kHz with the secondary ungrounded.

Quote
To get any significant output you need to drive it at (or close to) either the upper or lower pole of the coupled resonators.
So: tune the primary LC so that its uncoupled f0 is detuned to a frequency so low that we get the gain of the lower pole to be consistently higher than the gain of the upper pole, independent of the spark loading. Is that correct?

I guess the gain you are talking about is the gain of these poles in a spectral analysis of the RF radiated by the secondary? and also the primary in that case... and if such, a self oscillating circuit will 'lock on' to the frequency with the higher gain?

Offline Continuum

  • High Voltage Enthusiast
  • *
  • Posts: 7
  • Karma: +0/-0
    • View Profile
Re: help! GU-81M VTTC appears to be jumping between poles
« Reply #5 on: June 25, 2024, 10:19:04 PM »
Sorry for the double post, but i have made some "progress".
The frequency hopping goes away if i put the tickler coil above the primary. i guess that more capacitively coupled signal from the secondary helps.
If i tune so the driver operates at the lower pole, i still get very little output and a flashover at around half supply voltage. flashover looks like its between the anode and the cathode, doesnt happen inside the tubes structure, but between the "dish" on which the whole structure sits, and the anode. Ive tuned higher (closer to the f0 of the unloaded secondary); that gives me some nice sparks, which ciese growth quickly, (25 cm at best) but at least i dont get a flashover in the tube. I suppose that the spark growth ends once the sparks load the secondary so its frequency falls below the primary? im not sure. anyway, what could be causing so many flashovers?
why is the 'proper' tuning giving me this little ouput? i think that maybe tuning it so low causes no sparks at all, and thus it doesnt get a chance to come into tune, once the sparks would form and start growing. but still, why the flashovers? ive heard that if the oscillator cieses there could be a voltage spike, but im not sure why would that be. does anyone have any ideas? help, i dont want to kill my tube!
Edit: can it be that this weird frequency hopping is happening due to a resonance with the feedback coil? ive just calculated its f0 (2n2 and about 15 turns) and it seems that its bang on the frequency that i was trying to tune to, 650 kHz! but how would it resonate loaded only by the biasing resistor and the grid of the tube? would that even be an issue at all?
Edit 2: Well, it was not a resonance in the gridleak, nor was it a resonance of the psu LCL filter, but! the Q of my tank circuit was completely whack indeed, just about ~1, and it should be around 10 to 20 (source: people in the community say so  :P ). I have not been able to test if this helps much, as my tube sadly died before i was able to fix the overvoltage issue  :'(
« Last Edit: June 28, 2024, 11:52:53 PM by Continuum »

High Voltage Forum

Re: help! GU-81M VTTC appears to be jumping between poles
« Reply #5 on: June 25, 2024, 10:19:04 PM »

 


* Recent Topics and Posts

post Re: Problem with SSTC
[Solid State Tesla Coils (SSTC)]
Nunu00
July 12, 2024, 10:17:36 PM
post Making a HV prove
[Electronic Circuits]
Alberto
July 12, 2024, 09:01:08 PM
post Re: Problem with SSTC
[Solid State Tesla Coils (SSTC)]
davekni
July 12, 2024, 01:33:37 AM
post Re: Problem with SSTC
[Solid State Tesla Coils (SSTC)]
Nunu00
July 12, 2024, 12:17:32 AM
post Re: Restoring a Rogowski coil calibrator
[Capacitor Banks]
davekni
July 11, 2024, 07:38:26 PM
post Re: Restoring a Rogowski coil calibrator
[Capacitor Banks]
klugesmith
July 11, 2024, 06:30:00 PM
post LOD No Double Resonant SSTC?
[Solid State Tesla Coils (SSTC)]
ColinHeath
July 11, 2024, 06:08:30 PM
post Re: FIRST DRSSTC SKM400GB128D OCD SETTING
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Admiral Aaron Ravensdale
July 11, 2024, 12:24:56 PM
post Re: Strange QCW Streamer Behavior
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
July 11, 2024, 06:42:23 AM
post Re: Syntherrupter Lightsaber Sender Programming
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Cameron Prince
July 11, 2024, 05:46:07 AM
post Syntherrupter Lightsaber Sender Programming
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Cameron Prince
July 11, 2024, 05:26:51 AM
post Re: Strange QCW Streamer Behavior
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
July 11, 2024, 02:50:54 AM
post Strange QCW Streamer Behavior
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Coupling
July 11, 2024, 12:59:55 AM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic Circuits]
petespaco
July 10, 2024, 07:10:34 PM
post Re: Understanding and tracking upper and lower poles of QCW DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
July 10, 2024, 06:52:42 PM
post Re: Understanding and tracking upper and lower poles of QCW DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Anders Mikkelsen
July 10, 2024, 06:28:19 PM
post Re: FIRST DRSSTC SKM400GB128D OCD SETTING
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Alex_1996
July 10, 2024, 01:34:09 PM
post Re: Silicon(e) plasma
[General Chat]
alan sailer
July 10, 2024, 12:09:06 AM
post Re: Problem with SSTC
[Solid State Tesla Coils (SSTC)]
Nunu00
July 09, 2024, 11:52:00 PM
post Understanding and tracking upper and lower poles of QCW DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Simranjit
July 09, 2024, 07:37:22 PM
post Re: Silicon(e) plasma
[General Chat]
MechatEng2023
July 09, 2024, 07:30:05 PM
post Re: UD2.7C outputs very odd single square wave pulses
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
July 09, 2024, 03:30:49 AM
post Re: UD2.7C outputs very odd single square wave pulses
[Dual Resonant Solid State Tesla coils (DRSSTC)]
verliebt_in_neukölln17
July 09, 2024, 12:51:02 AM
post Re: UD2.7C outputs very odd single square wave pulses
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
July 08, 2024, 11:30:44 PM
post Re: Why so cheap?
[General Chat]
alan sailer
July 08, 2024, 10:57:10 PM
post UD2.7C outputs very odd single square wave pulses
[Dual Resonant Solid State Tesla coils (DRSSTC)]
verliebt_in_neukölln17
July 08, 2024, 10:21:01 PM
post Why so cheap?
[General Chat]
MRMILSTAR
July 08, 2024, 09:55:24 PM
post Re: Syntherrupter - A Feature-rich, Polyphonic Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Cameron Prince
July 08, 2024, 09:18:21 PM
post Re: Syntherrupter - A Feature-rich, Polyphonic Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
July 08, 2024, 05:17:49 PM
post Re: Syntherrupter - A Feature-rich, Polyphonic Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Cameron Prince
July 08, 2024, 04:49:20 PM
post Re: Tesla coil in FEMM
[Beginners]
Simranjit
July 08, 2024, 04:28:43 AM
post Re: Tesla coil in FEMM
[Beginners]
davekni
July 08, 2024, 04:06:53 AM
post Tesla coil in FEMM
[Beginners]
Simranjit
July 08, 2024, 03:46:49 AM
post Re: Best core material for QCW Buck modulator ?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Simranjit
July 08, 2024, 02:42:00 AM
post Re: QCWDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
July 08, 2024, 01:37:55 AM
post Re: First DRSSTC Build- Issues with Fibernet project
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Sebigamer
July 08, 2024, 12:53:08 AM
post Re: QCWDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Anders Mikkelsen
July 08, 2024, 12:49:48 AM
post Re: Silicon(e) plasma
[General Chat]
alan sailer
July 07, 2024, 11:15:35 PM
post Silicon(e) plasma
[General Chat]
MechatEng2023
July 07, 2024, 11:04:43 PM
post Re: QCWDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
July 07, 2024, 09:39:07 PM
post Re: First DRSSTC Build- Issues with Fibernet project
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
July 07, 2024, 05:32:56 PM
post Re: QCWDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Anders Mikkelsen
July 07, 2024, 02:52:19 PM
post Re: No change in Phase Lead
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Anders Mikkelsen
July 07, 2024, 02:50:04 PM
post Re: Best core material for QCW Buck modulator ?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Anders Mikkelsen
July 07, 2024, 02:20:11 PM
post Teardown of a APC SmartUPS VT 40 kVA
[Electronic Circuits]
Mads Barnkob
July 07, 2024, 10:02:22 AM
post First DRSSTC Build- Issues with Fibernet project
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Sebigamer
July 07, 2024, 09:23:58 AM
post Re: QCWDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
July 07, 2024, 12:44:53 AM
post Re: FEMM tesla coil simulation
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Simranjit
July 07, 2024, 12:08:50 AM
post Re: FEMM tesla coil simulation
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
July 06, 2024, 10:35:49 PM
post FEMM tesla coil simulation
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Simranjit
July 06, 2024, 09:42:43 PM
post Re: No change in Phase Lead
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
July 06, 2024, 06:06:23 PM
post Re: No change in Phase Lead
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Admiral Aaron Ravensdale
July 06, 2024, 10:21:16 AM
post Re: No change in Phase Lead
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Admiral Aaron Ravensdale
July 06, 2024, 10:15:42 AM
post Re: QCWDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Simranjit
July 06, 2024, 04:53:56 AM
post Re: No change in Phase Lead
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
July 06, 2024, 04:42:16 AM
post Re: QCWDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
July 06, 2024, 04:09:50 AM
post Re: Best core material for QCW Buck modulator ?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
July 06, 2024, 03:07:11 AM
post Re: No change in Phase Lead
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
July 06, 2024, 03:05:18 AM
post Re: QCWDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
July 06, 2024, 02:37:16 AM
post Re: QCWDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Simranjit
July 06, 2024, 02:20:14 AM
post QCWDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
July 06, 2024, 01:55:14 AM
post Re: No change in Phase Lead
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
July 05, 2024, 11:50:37 PM
post Best core material for QCW Buck modulator ?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Simranjit
July 05, 2024, 10:07:04 PM
post 230v Tesla coil and krypton gas
[Spark Gap Tesla Coils (SGTC)]
gravitysrainbow
July 05, 2024, 07:13:25 PM
post Re: No change in Phase Lead
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Admiral Aaron Ravensdale
July 05, 2024, 06:17:13 PM
post Re: Phase lead inductors
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
July 04, 2024, 11:40:45 PM
post Re: Sling Psychrometer
[Laboratories, Equipment and Tools]
Twospoons
July 04, 2024, 11:02:32 PM
post Phase lead inductors
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
July 04, 2024, 06:28:08 PM
post Re: Sling Psychrometer
[Laboratories, Equipment and Tools]
klugesmith
July 04, 2024, 12:31:40 AM
post Re: FIRST DRSSTC SKM400GB128D OCD SETTING
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Alex_1996
July 04, 2024, 12:07:21 AM
post Re: FIRST DRSSTC SKM400GB128D OCD SETTING
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Alex_1996
July 04, 2024, 12:06:17 AM
post Re: FIRST DRSSTC SKM400GB128D OCD SETTING
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
July 03, 2024, 10:51:23 PM
post Re: FIRST DRSSTC SKM400GB128D OCD SETTING
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
July 03, 2024, 09:44:14 PM
post Re: Coax cable for DRSSTC interrupter?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Admiral Aaron Ravensdale
July 03, 2024, 08:48:13 PM
post Re: Coax cable for DRSSTC interrupter?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Simranjit
July 03, 2024, 08:24:50 PM
post Re: FIRST DRSSTC SKM400GB128D OCD SETTING
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Alex_1996
July 03, 2024, 08:12:55 PM
post Re: Coax cable for DRSSTC interrupter?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Admiral Aaron Ravensdale
July 03, 2024, 07:29:53 PM
post Re: FIRST DRSSTC SKM400GB128D OCD SETTING
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Admiral Aaron Ravensdale
July 03, 2024, 07:21:38 PM
post Re: FIRST DRSSTC SKM400GB128D OCD SETTING
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
July 03, 2024, 05:05:39 PM
post Re: FIRST DRSSTC SKM400GB128D OCD SETTING
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Alex_1996
July 03, 2024, 04:29:53 PM
post Re: FIRST DRSSTC SKM400GB128D OCD SETTING
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
July 03, 2024, 04:09:11 PM
post FIRST DRSSTC SKM400GB128D OCD SETTING
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Alex_1996
July 03, 2024, 02:47:18 PM
post Re: Eliminating discharges from a SSTC
[Solid State Tesla Coils (SSTC)]
Alex_1996
July 03, 2024, 01:35:24 PM
post Re: Coax cable for DRSSTC interrupter?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
July 03, 2024, 02:19:03 AM
post Re: Coax cable for DRSSTC interrupter?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
verliebt_in_neukölln17
July 03, 2024, 01:19:50 AM
post Coax cable for DRSSTC interrupter?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Simranjit
July 02, 2024, 11:29:18 PM
post Re: Is this a good pulse experiment capacitor?
[Capacitor Banks]
Mads Barnkob
July 02, 2024, 09:59:07 PM
post Re: LabCoatz Staccato QCW No straight sparks
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
July 02, 2024, 09:55:53 PM
post Re: Capacitor wiring for single phase 240 to split phase (180 degree) 240v
[Capacitor Banks]
klugesmith
July 02, 2024, 09:44:55 PM
post Re: LabCoatz Staccato QCW No straight sparks
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Admiral Aaron Ravensdale
July 02, 2024, 07:51:37 PM
post Re: LabCoatz Staccato QCW No straight sparks
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
July 02, 2024, 06:14:07 PM
post Is this a good pulse experiment capacitor?
[Capacitor Banks]
FPS
July 02, 2024, 06:02:38 PM
post Re: LabCoatz Staccato QCW No straight sparks
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Admiral Aaron Ravensdale
July 02, 2024, 11:37:46 AM
post Re: Building my first DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
July 02, 2024, 05:22:10 AM
post Re: Coulometric hourmeters
[Laboratories, Equipment and Tools]
davekni
July 02, 2024, 05:16:30 AM
post Re: Building my first DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
drobotk
July 01, 2024, 11:50:12 PM
post Re: Restoring a Rogowski coil calibrator
[Capacitor Banks]
klugesmith
July 01, 2024, 08:48:53 PM
post Uses for Weston's Little Bee probe
[Laboratories, Equipment and Tools]
klugesmith
July 01, 2024, 08:40:59 AM
post Re: Coulometric hourmeters
[Laboratories, Equipment and Tools]
klugesmith
July 01, 2024, 08:09:42 AM
post Re: Coulometric hourmeters
[Laboratories, Equipment and Tools]
davekni
June 30, 2024, 06:49:45 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