Author Topic: MMC capacitor crash  (Read 1164 times)

Offline JCF

  • High Voltage Experimenter
  • **
  • Posts: 71
  • Karma: +1/-0
    • View Profile
MMC capacitor crash
« on: August 27, 2022, 12:11:53 PM »
Hello everyone, I experienced 2 crashes of my MMC this year with Cornell-Dubilier 940C 47nF 3kV dc ±10% Thin Film Capacitor

First crash capacitor exploded
second opening crash and black leak on the IC
The operating voltage was 200Vdc.
The MMC is a combination of 3 x 3 capacitor.

What append ? 200Vdc is low, Is this a problem with the pulse width being too large? A failure of a capacitor (always at the beginning of one of the rows of the MMC
What is the maximum pulse width not to exceed, frequency around 20Hz

For the design of the tesla coil see https://highvoltageforum.net/index.php?topic=1695.msg13172#msg13172





Offline Mike

  • High Voltage Enthusiast
  • *
  • Posts: 40
  • Karma: +3/-0
    • View Profile
Re: MMC capacitor crash
« Reply #1 on: August 27, 2022, 12:59:42 PM »
From the datasheet we can see that your individual caps are rated for 68A pk and 5.7A rms. Your 3x3 MMC is rated for 3 times that so 204A pk and 17.1A rms. If your frequency is 20Hz and you're under the peak current rating, that makes the maximum pulse width about 420us.

You also need to check the maximum voltage you're exposing your capacitor to. This is found by calculating the capacitors impedance at your resonant frequency (Xc = 1 / (2πfC)) and multiplying that by your peak resonant current. If your peak voltage is less than the rated DC voltage you're probably ok.
« Last Edit: August 27, 2022, 01:02:42 PM by Mike »

Offline Mads Barnkob

  • Administrator
  • Executive Board Member
  • *****
  • Posts: 2022
  • Karma: +53/-0
  • Denmark
    • View Profile
    • Kaizer Power Electronics
Re: MMC capacitor crash
« Reply #2 on: August 27, 2022, 01:08:42 PM »
What does the backside of that MMC look like? Since you say its always the first row, sounds like you have a load imbalance or capacitance imbalance, which would result in a load imbalance...

You can check your MMC design fast with the MMC calculator: https://kaizerpowerelectronics.dk/calculators/mmc-calculator/

As Mike notes, 420us maximum pulse width is lower than the 750us you said you were running it at, which means you cooked them from excessive heat dissipation.
https://kaizerpowerelectronics.dk - Tesla coils, high voltage, pulse power, audio and general electronics
https://www.youtube.com/KaizerPowerElectronicsDk60/join - Please consider supporting the forum, websites and youtube channel!

Offline JCF

  • High Voltage Experimenter
  • **
  • Posts: 71
  • Karma: +1/-0
    • View Profile
Re: MMC capacitor crash
« Reply #3 on: August 27, 2022, 04:15:18 PM »
the rear wiring is essentially made with the tails of the capacitors and resistors. it's not massive at all. if it takes a piece of copper of 2mm diameter I will do something more consistent.

for the connection with the bridge and the primary, it is a large multi-strand copper wire 6 mm2 top left and bottom right

résonance frequency of coil is 130khz

the wiring is really very badly made ....!



* Spec Capacitor.pdf

« Last Edit: August 27, 2022, 04:40:11 PM by JCF »

Offline klugesmith

  • High Voltage Senior
  • *****
  • Posts: 514
  • Karma: +16/-0
    • View Profile
Re: MMC capacitor crash
« Reply #4 on: August 27, 2022, 05:08:30 PM »
>> if it takes a piece of copper of 2mm diameter I will do something more consistent.

Mads warned of un-balanced currents in the MMC.
In your case, the partition of current between three branches is affected by inductance much more than wire resistance.
Adding copper without moving the capacitors and changing loop areas won't make much of a difference. 

Offline Mads Barnkob

  • Administrator
  • Executive Board Member
  • *****
  • Posts: 2022
  • Karma: +53/-0
  • Denmark
    • View Profile
    • Kaizer Power Electronics
Re: MMC capacitor crash
« Reply #5 on: August 27, 2022, 07:32:02 PM »
It is the results with your primary coil inductance for the MMC calculator that is interesting, not the first part you screenshotted :) The bottom results of what the MMC specifications are and what they actually see at load.

Please take out the MMC for a proper picture of the backside, its impossible to evaluate the wiring from that picture. It looks like you did connect in opposite corners, but did you put everything in parallel / series like a matrice? It should just be parallel strings, not connections between the strings in the middle of them.
https://kaizerpowerelectronics.dk - Tesla coils, high voltage, pulse power, audio and general electronics
https://www.youtube.com/KaizerPowerElectronicsDk60/join - Please consider supporting the forum, websites and youtube channel!

Offline JCF

  • High Voltage Experimenter
  • **
  • Posts: 71
  • Karma: +1/-0
    • View Profile
Re: MMC capacitor crash
« Reply #6 on: August 28, 2022, 10:55:18 AM »
thank for help
MMC is 3 lines of 3 capacitors in serie with // resistors, each line connected at right and left in paralell.

« Last Edit: August 28, 2022, 04:27:33 PM by JCF »

Online davekni

  • High Voltage Expert
  • ******
  • Posts: 1790
  • Karma: +88/-1
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: MMC capacitor crash
« Reply #7 on: August 28, 2022, 09:01:47 PM »
Quote
thank for help
MMC is 3 lines of 3 capacitors in serie with // resistors, each line connected at right and left in paralell.
Three possible causes of failure come to mind:
1) Perhaps there's a wiring mistake and it's not as intended (not as attached diagram in last post).
2) MMC wiring is spaced so close that arcs form between wires.
3) Higher RMS current than capacitors can handle.
My first guess would be (3).  Have you checked capacitor temperature immediately after a run?  What duty-cycle are you running (burst length as a fraction of period from one burst to the next) and what primary current?

Film capacitors such as these usually fail somewhat gradually before final rupture.  Capacitance drops first, then leakage current goes up, then failure.  I'd suggest measuring each capacitor to see if you have others that are on their way toward failure.  Within MMC array, measured value for any individual capacitor will include some contribution from remainder of MMC, so will measure ~28% high in your case.  Still useful in comparing readings of all 9 capacitors.
« Last Edit: August 28, 2022, 09:24:08 PM by davekni »
David Knierim

Offline Hydron

  • Administrator
  • High Voltage Engineer
  • *****
  • Posts: 446
  • Karma: +19/-0
    • View Profile
Re: MMC capacitor crash
« Reply #8 on: August 29, 2022, 09:40:10 AM »
It is the results with your primary coil inductance for the MMC calculator that is interesting, not the first part you screenshotted :) The bottom results of what the MMC specifications are and what they actually see at load.

Please take out the MMC for a proper picture of the backside, its impossible to evaluate the wiring from that picture. It looks like you did connect in opposite corners, but did you put everything in parallel / series like a matrice? It should just be parallel strings, not connections between the strings in the middle of them.
I would run the impedance numbers at the operating frequency before worrying about the layout too much - I suspect that you'd find that the wiring between parallel strings of caps would need to be seriously inductive (a big coil or something) to make a noticeable difference in current sharing.
Remember that at the resonant frequency the primary coil impedance is the same as the MMC impedance, so a little bit of extra wire will make very little difference compared to the impedance of the cap string. This is not like trying to share current between parallel connector pins or something (where the contact impedance is probably the biggest and most variable impedance) - the capacitor strings each have their own, large (compared to the inductance of the bus-bar) impedance, which will force current sharing.
« Last Edit: August 29, 2022, 09:42:10 AM by Hydron »

Offline JCF

  • High Voltage Experimenter
  • **
  • Posts: 71
  • Karma: +1/-0
    • View Profile
Re: MMC capacitor crash
« Reply #9 on: August 30, 2022, 04:40:33 PM »
Hello,
here are the photos of the MMC on the wiring side, and the lower part and cable of the coil.
I removed the small piece of solder on the body of one of the resistors, this is not a defect.

I will take measurements soon (primary current, Max spike at output bridge : IGBTCM200DU-12F (600V 200A).

the capacitors all have approximately the same capacitance value.


« Last Edit: August 30, 2022, 05:01:58 PM by JCF »

Online davekni

  • High Voltage Expert
  • ******
  • Posts: 1790
  • Karma: +88/-1
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: MMC capacitor crash
« Reply #10 on: August 31, 2022, 03:44:57 AM »
Quote
here are the photos of the MMC on the wiring side, and the lower part and cable of the coil.
Don't see any issues in MMC wiring.  I'd guess just too-high duty cycle making RMS current high, overheating capacitors.  There will be hot-spots within capacitor.  Still, I'd expect overall case temperature to be fairly warm if RMS current is the issue.

Quote
the capacitors all have approximately the same capacitance value.
Roughly how much variation?  Can be difficult to detect issues without knowing initial capacitance.  The caps I've tested to destruction drop only 5-10% before failure.

Quote
I will take measurements soon (primary current, Max spike at output bridge : IGBTCM200DU-12F (600V 200A).
That will be useful.  Needs to include duty cycle information as well (repetition rate and duration of primary current within each burst).

Good luck with avoiding future failures!
David Knierim

Offline JCF

  • High Voltage Experimenter
  • **
  • Posts: 71
  • Karma: +1/-0
    • View Profile
Re: MMC capacitor crash
« Reply #11 on: September 01, 2022, 11:52:13 AM »
Thank you for your help which I appreciate
what brand of capacitors should be purchased to avoid overcharging problems? on eBay?

Offline Mads Barnkob

  • Administrator
  • Executive Board Member
  • *****
  • Posts: 2022
  • Karma: +53/-0
  • Denmark
    • View Profile
    • Kaizer Power Electronics
Re: MMC capacitor crash
« Reply #12 on: September 01, 2022, 11:15:05 PM »
Thank you for your help which I appreciate
what brand of capacitors should be purchased to avoid overcharging problems? on eBay?

It is your design or how hard you drive them, that has to change. You were already using CDE 940 series pulse capacitors, some of the best known/well proven Tesla coiling durable MMC capacitors.

If you want something that can withstand the abuse you gave to these, look for GTO snubber capacitor, DC bus snubbers or resonant capacitors. But these you can all kill from driving them hard outside of their thermal limits, like you did with the CDE 940s
https://kaizerpowerelectronics.dk - Tesla coils, high voltage, pulse power, audio and general electronics
https://www.youtube.com/KaizerPowerElectronicsDk60/join - Please consider supporting the forum, websites and youtube channel!

Offline JCF

  • High Voltage Experimenter
  • **
  • Posts: 71
  • Karma: +1/-0
    • View Profile
Re: MMC capacitor crash
« Reply #13 on: September 02, 2022, 11:53:33 AM »
Thanks for the warnings about the duty cycle
I will therefore do measurements + calculation to see what is happening at the level of the MMC

Offline JCF

  • High Voltage Experimenter
  • **
  • Posts: 71
  • Karma: +1/-0
    • View Profile
Re: MMC capacitor crash
« Reply #14 on: September 13, 2022, 06:00:00 PM »
Hello. I pulled out the material to make measure…. I do not understand what is happening with the appearance of the primary signal (with differential probe) ? ?
Vdc : 60/70V at full bridge. Current transformer 1/300 on 100 Ohms. No OCD connected
Too much coupling ?




third pict is what I had several months ago before the crash of the MMC (repair I change two capacitors)




« Last Edit: September 15, 2022, 04:22:13 PM by JCF »

Offline JCF

  • High Voltage Experimenter
  • **
  • Posts: 71
  • Karma: +1/-0
    • View Profile
Re: MMC capacitor crash
« Reply #15 on: September 14, 2022, 03:43:03 PM »
Hi measurements of the day with a generator on the feedback
the frequency of the generator is marked in the filename.
what deduce the frequency of the primary is too close ?


« Last Edit: September 14, 2022, 03:50:14 PM by JCF »

Online davekni

  • High Voltage Expert
  • ******
  • Posts: 1790
  • Karma: +88/-1
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: MMC capacitor crash
« Reply #16 on: September 15, 2022, 05:54:55 AM »
All of your new scope captures appear to show little energy transfer to secondary.  Current rises higher for a given bus voltage with no obvious cyclic nature of current growth (beat frequency between primary and secondary) as shows up in the one old scope capture image.  I'd guess either far-mismatched primary and secondary frequencies or little coupling.  Mismatched frequencies could be due to a missing top load or secondary ground, anything that changes secondary resonant frequency.

A couple other observations:
1) A couple of the latest images show clipping (over-voltage) of your differential probe.  Change to 500x mode.
2) Differential probe connection and/or H-bridge has significant inductance, adding LdV/dt to H-bridge output signal.  If you can, run differential probe wires from H-bridge the opposite direction as connections to MMC and primary coil.  Twist or otherwise pair together probe leads.
3) Dead-time looks good.  Shows up in triple-transitions on SDS00155k25_02.png image.
David Knierim

Offline JCF

  • High Voltage Experimenter
  • **
  • Posts: 71
  • Karma: +1/-0
    • View Profile
Re: MMC capacitor crash
« Reply #17 on: September 15, 2022, 04:15:12 PM »
thanks very much Dave. I did not understand very well.
do I have to understand that the first oscillogram was good ?  SDS00004.png (with feed back secondary connected). I thought I saw a square signal and is no the case



"If you can, run differential probe wires from H-bridge the opposite direction as connections to MMC and primary coil...."  is reverse differential probe ? currently I am on the output of the bridge.
 
« Last Edit: September 15, 2022, 05:17:51 PM by JCF »

Online davekni

  • High Voltage Expert
  • ******
  • Posts: 1790
  • Karma: +88/-1
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: MMC capacitor crash
« Reply #18 on: September 16, 2022, 05:40:05 AM »
Quote
do I have to understand that the first oscillogram was good ?  SDS00004.png (with feed back secondary connected). I thought I saw a square signal and is no the case
Am I correct that SDS00012.png is the a capture from before MMC crash?  That capture looks good with one exception: H-bridge voltage phase is lagging current rather than slightly leading as is preferred.  SDS00012.png shows periodic increases in primary current as would be expected for coupled resonators.  SDS00004.png shows primary current ramping continuously to about 3x the current shown in SDS00012.png.  Both the higher current and lack of periodicity in increase indicate energy is not transferring to secondary.  BTW, at least the zoomed-in capture SDS00003.png shows sufficient phase lead.

Quote
"If you can, run differential probe wires from H-bridge the opposite direction as connections to MMC and primary coil...."  is reverse differential probe ? currently I am on the output of the bridge.
Connecting to H-bridge output is correct.    I'm suggesting only that the probe wires be routed a different direction and connected to the output as close to IGBTs as is reasonable.  How were scope wires routed for your old SDS00012.png capture?  That capture shows less of the sine-wave current signal added to H-bridge output.  Newer captures all show large sine-wave current signal added to H-bridge voltage.  That makes interpreting the traces more difficult.  That sine-wave current signal is not likely real at the IGBTs.  It gets added by either common inductance (scope leads connected to H-bridge output farther away from IGBTs, closer to MMC or primary coil) or by mutual inductance (scope probe wires not paired close to each other with magnetic field from primary coil or leads passing between scope probe wires).
David Knierim

Offline JCF

  • High Voltage Experimenter
  • **
  • Posts: 71
  • Karma: +1/-0
    • View Profile
Re: MMC capacitor crash
« Reply #19 on: September 16, 2022, 04:17:31 PM »
Thanks David
I realize that I did very little measurement around the resonance frequency
here generator input feedback f = 153khz
fiber optic input 10 Hz 200µS.
Vdc bus 60Vdc



on 3 captures I see more or less long traces for the primary
the sound of the spark is more or less loud.
why this change in length ? instability ? vbus too low,

what to do ? it's normal ?

the first and last trace shows a frequency very close to 152.60 with a different length for primary signal ?




« Last Edit: September 16, 2022, 04:40:23 PM by JCF »

Offline Mads Barnkob

  • Administrator
  • Executive Board Member
  • *****
  • Posts: 2022
  • Karma: +53/-0
  • Denmark
    • View Profile
    • Kaizer Power Electronics
Re: MMC capacitor crash
« Reply #20 on: September 16, 2022, 08:32:01 PM »
SDS00004.png shows a normal classic voltage transient inverter situation where current ramps too high and the DC bus is pulled down, which then limits current and DC bus crawls back up again as the MMC from from empty (a short circuit to the inverter) to less load and current falls. As Dave says, this is a sign of no energy transfer.

random example from the Internet(tm)


However, the latest SDS00155.jpg shows that you have a ringup of about 200 uS, 200 us additional where it falls abit and goes into steady state for 600+ us. The steady state shows a continues energy transfer to the secondary circuit, energy fed into the inverter goes all the way to the spark. It does not help the spark growth, it just keeps it on for a longer time. Your spark growth is all in the ringup.
https://kaizerpowerelectronics.dk - Tesla coils, high voltage, pulse power, audio and general electronics
https://www.youtube.com/KaizerPowerElectronicsDk60/join - Please consider supporting the forum, websites and youtube channel!

Online davekni

  • High Voltage Expert
  • ******
  • Posts: 1790
  • Karma: +88/-1
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: MMC capacitor crash
« Reply #21 on: September 16, 2022, 09:04:59 PM »
Quote
here generator input feedback f = 153khz
As Mads has pointed out in other posts, running open-loop can lead to IGBT failures due to excess hard-switching (IGBTs switching at high current parts of the waveform).  Certainly keep Vbus low as you have been for such testing.

I'm guessing that SDS00153.jpg is slightly below primary resonant frequency.  Running open-loop (from signal generator) below resonance causes phase lag.  That is the most risky (for IGBT failure) condition where turn-on is after current reverses.  Resulting switching spikes are clipped in scope capture, presumably because your differential probe is still set for 50x rather than 500x.

Quote
why this change in length ? instability ? vbus too low,
All three traces show operation longer than 200us.  If your interrupter is set for 200us, either your interrupter or driver board is not functioning correctly.  I suggest finding and fixing that issue first.  If pulses are lasting much longer than interrupter is requesting, that could have been the initial cause of MMC crash, much higher duty cycles than you intended.

Quote
SDS00004.png shows a normal classic voltage transient inverter situation where current ramps too high and the DC bus is pulled down, which then limits current and DC bus crawls back up again as the MMC from from empty (a short circuit to the inverter) to less load and current falls.
With respect for Mads' experience, I think this isn't the case here.  Inductance in the differential probe connection to H-bridge output confuses the image.  The individual H-bridge output steps can still be seen, and decrease in amplitude only slightly across SDS00004.png capture.  Also, primary current rise rate decreases only slightly, indicating Vbus is still close to its initial value.  Your scope captures will be easier to understand if differential probe connection can be improved.  Can you post a picture of probe connection including probe leads?

David Knierim

Offline Mads Barnkob

  • Administrator
  • Executive Board Member
  • *****
  • Posts: 2022
  • Karma: +53/-0
  • Denmark
    • View Profile
    • Kaizer Power Electronics
Re: MMC capacitor crash
« Reply #22 on: September 16, 2022, 09:48:56 PM »
Quote
SDS00004.png shows a normal classic voltage transient inverter situation where current ramps too high and the DC bus is pulled down, which then limits current and DC bus crawls back up again as the MMC from from empty (a short circuit to the inverter) to less load and current falls.
With respect for Mads' experience, I think this isn't the case here.  Inductance in the differential probe connection to H-bridge output confuses the image.  The individual H-bridge output steps can still be seen, and decrease in amplitude only slightly across SDS00004.png capture.  Also, primary current rise rate decreases only slightly, indicating Vbus is still close to its initial value.  Your scope captures will be easier to understand if differential probe connection can be improved.  Can you post a picture of probe connection including probe leads?

It was not as based on my own experience, as it was more based on similar waveforms in inverters.

I will stand corrected if that is the case :) I have never seen so bad measurements with a differential probe, but then again, I assumed the measurement here is not to blame. But definately worth checking up upon with some pictures.

https://kaizerpowerelectronics.dk - Tesla coils, high voltage, pulse power, audio and general electronics
https://www.youtube.com/KaizerPowerElectronicsDk60/join - Please consider supporting the forum, websites and youtube channel!

Offline JCF

  • High Voltage Experimenter
  • **
  • Posts: 71
  • Karma: +1/-0
    • View Profile
Re: MMC capacitor crash
« Reply #23 on: September 18, 2022, 05:22:31 PM »
Merci pour l'aide !
here are 2 photos that show the box with primary and details of HV probes connected to the bridge output.


with toroid on feedback I see f=  151.6khz is it  necessary to adjust the frequency of the primary to 153khz. 153khz is maximum spark lenght ? ?
the instability came from the contact on the aluminum crown : it is ok now.
sense for current is 1:300 on 100 ohms.
input fiber optic signal 200µS and 10hz sqare

it seems to be working fine ?




« Last Edit: September 18, 2022, 05:43:05 PM by JCF »

Online davekni

  • High Voltage Expert
  • ******
  • Posts: 1790
  • Karma: +88/-1
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: MMC capacitor crash
« Reply #24 on: September 19, 2022, 12:09:22 AM »
Quote
here are 2 photos that show the box with primary and details of HV probes connected to the bridge output.
The unusual H-bridge output scope traces are due to inductance of wires from IGBTs to front edge of the black box.  If it isn't too hard, run a second pair of wires (may be smaller wire) from IGBTs (H-bridge output) to the back side of the black box.  Connect scope probe to those new wires instead of to wires connected to MMC and primary coil.  That will avoid most wiring inductance that is common to both primary coil path and scope path.  Scope traces will look more like square waves.  Any subtle issues will be easier to see and correctly interpret that way.

Quote
with toroid on feedback I see f=  151.6khz is it  necessary to adjust the frequency of the primary to 153khz. 153khz is maximum spark lenght ? ?
By "toroid", I'm presuming you refer to the feedback current transformer, not the top-load aluminum toroid.  If UD2.7 phase-lead is adjusted optimally, I'd expect it to oscillate at 153kHz based on previous open-loop (signal generator driven) scope traces.  However, that 151.6kHz to 153kHz is a tiny difference, not that significant.  For maximum spark length, primary frequency needs to be a little below secondary frequency.  Enough below so that it matches secondary frequency as secondary frequency drops due to spark loading (spark capacitance).  JaveTC is a good way to model primary and secondary frequencies (and coupling factor etc.).  Include wire length in JavaTC input since your primary wire length is significant.  (In general, I'd recommend pairing primary leads closer together to reduce wire inductance.  That will increase primary frequency slightly, so might require adjusting primary coil to compensate.)

Quote
it seems to be working fine ?
Looks fine in that pulses last 200us as intended.  Still don't see as much evidence of power transfer to secondary as shows up in the one old scope capture SDS000004.  That makes me suspect secondary frequency isn't close enough to 153kHz in this test.

Quote
Merci pour l'aide !
You are certainly welcome!  (Google translate worked well on this short phrase.)

Good luck!
David Knierim

High Voltage Forum

Re: MMC capacitor crash
« Reply #24 on: September 19, 2022, 12:09:22 AM »

 


* Recent Topics and Posts

post What am I missing?!?!?
[Spark Gap Tesla Coils (SGTC)]
Conrad73
Today at 06:35:43 PM
post Radiometer Copenhagen OSG 42b Oscilloscope Repair, From The 1950'ish
[Laboratories, Equipment and Tools]
Mads Barnkob
Today at 03:18:22 PM
post Re: Recommended development boards for QCWDRSSTC
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Rafft
Today at 02:53:30 PM
post Recommended development boards for QCWDRSSTC
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
dru
Today at 09:05:37 AM
post Re: Ud failure
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
Today at 08:29:09 AM
post Re: Ud failure
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
Today at 05:27:41 AM
post Re: Gauss meter for strong magnetic fields
[Laboratories, Equipment and Tools]
klugesmith
Today at 02:12:21 AM
post Ud failure
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
Today at 01:50:45 AM
post Re: controlling the negative gate bias voltage of the Gate drive transformer
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 24, 2022, 09:36:58 PM
post UD2.x mod
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rafft
September 24, 2022, 05:06:28 PM
post Re: Gate drive transformer with negative gate bias voltage
[Dual Resonant Solid State Tesla coils (DRSSTC)]
prabhatkumar
September 24, 2022, 06:56:35 AM
post Re: Gate drive transformer with negative gate bias voltage
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 24, 2022, 06:09:03 AM
post Re: Gauss meter for strong magnetic fields
[Laboratories, Equipment and Tools]
davekni
September 24, 2022, 01:32:08 AM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
mthome4
September 23, 2022, 10:55:21 PM
post Re: Gauss meter for strong magnetic fields
[Laboratories, Equipment and Tools]
AstRii
September 23, 2022, 10:39:13 PM
post controlling the negative gate bias voltage of the Gate drive transformer
[Dual Resonant Solid State Tesla coils (DRSSTC)]
prabhatkumar
September 23, 2022, 05:48:17 PM
post Gauss meter for strong magnetic fields
[Laboratories, Equipment and Tools]
Peregrine
September 23, 2022, 02:01:10 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 23, 2022, 03:04:31 AM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 22, 2022, 04:15:36 PM
post Re: SSTC - PCB design
[Beginners]
Przemekk00
September 22, 2022, 12:39:51 PM
post Re: Possible Leads on Single Photon Camera
[General Chat]
alan sailer
September 22, 2022, 12:05:55 AM
post Re: Possible Leads on Single Photon Camera
[General Chat]
Mads Barnkob
September 21, 2022, 10:32:29 PM
post Possible Leads on Single Photon Camera
[General Chat]
alan sailer
September 21, 2022, 03:57:38 PM
post Re: Driverless Single Mosfet Relay interrupted SSTC? - [All kinds of problems]
[Solid State Tesla Coils (SSTC)]
davekni
September 21, 2022, 05:50:15 AM
post Re: Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
RoamingD
September 20, 2022, 10:29:41 PM
post Re: Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
September 20, 2022, 08:24:30 PM
post Re: Driverless Single Mosfet Relay interrupted SSTC? - [All kinds of problems]
[Solid State Tesla Coils (SSTC)]
TiagoBS
September 20, 2022, 06:23:54 PM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 20, 2022, 05:20:07 AM
post Re: TO247 mounting
[Beginners]
davekni
September 20, 2022, 05:15:35 AM
post Re: MidiStick V2.0: Next gen tesla coil interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
TMaxElectronics
September 19, 2022, 11:43:47 PM
post Re: TO247 mounting
[Beginners]
Weston
September 19, 2022, 09:58:56 PM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
mthome4
September 19, 2022, 09:05:35 PM
post Re: Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
RoamingD
September 19, 2022, 12:58:35 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 19, 2022, 12:13:46 AM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 19, 2022, 12:09:22 AM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 18, 2022, 11:38:51 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 18, 2022, 10:41:54 PM
post Re: Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
davekni
September 18, 2022, 10:31:32 PM
post Re: Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
RoamingD
September 18, 2022, 10:09:33 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 18, 2022, 09:58:34 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 18, 2022, 08:45:21 PM
post Re: Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
September 18, 2022, 07:55:11 PM
post Re: Syntherrupter - A Feature-rich, Polyphonic Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
September 18, 2022, 07:25:30 PM
post TO247 mounting
[Beginners]
mthome4
September 18, 2022, 06:32:10 PM
post Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
RoamingD
September 18, 2022, 05:48:17 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 18, 2022, 05:44:14 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
JCF
September 18, 2022, 05:22:31 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 18, 2022, 06:10:33 AM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 18, 2022, 12:47:41 AM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 17, 2022, 06:37:23 PM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
mthome4
September 17, 2022, 11:56:26 AM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 17, 2022, 01:50:27 AM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
mthome4
September 16, 2022, 11:05:46 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
September 16, 2022, 09:48:56 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 16, 2022, 09:04:59 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
September 16, 2022, 08:32:01 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
JCF
September 16, 2022, 04:17:31 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 16, 2022, 05:40:05 AM
post Re: Getting last joules out of batteries
[Laboratories, Equipment and Tools]
klugesmith
September 15, 2022, 11:18:56 PM
post Re: SALE(US) - 30 amp 3 phase GE volt-pac variac auto transformer 0-520v
[Sell / Buy / Trade]
rikkitikkitavi
September 15, 2022, 10:16:03 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
JCF
September 15, 2022, 04:15:12 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 15, 2022, 05:54:55 AM
post Re: Getting last joules out of batteries
[Laboratories, Equipment and Tools]
Weston
September 14, 2022, 10:36:37 PM
post Re: Help with PLL induction heater driver
[Electronic Circuits]
dbach
September 14, 2022, 09:09:09 PM
post Re: Few questions before a TC show
[Dual Resonant Solid State Tesla coils (DRSSTC)]
AstRii
September 14, 2022, 06:47:04 PM
post Re: The most powerful Russian Tesla coil in Europe (and maybe in the world)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
hammertone
September 14, 2022, 04:45:43 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
JCF
September 14, 2022, 03:43:03 PM
post Re: SSTC - PCB design
[Beginners]
davekni
September 14, 2022, 06:38:17 AM
post Re: Sources for optical parts?
[Light, Lasers and Optics]
klugesmith
September 14, 2022, 02:16:33 AM
post Re: Circuit drawing software for dummies
[Printed Circuit Board]
Twospoons
September 14, 2022, 12:31:44 AM
post Re: Sources for optical parts?
[Light, Lasers and Optics]
Twospoons
September 13, 2022, 10:21:13 PM
post Re: The most powerful Russian Tesla coil in Europe (and maybe in the world)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
September 13, 2022, 10:20:28 PM
post Re: Where to find a "small" focal spot x-ray tube
[X-ray]
Fijcho
September 13, 2022, 10:05:48 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
JCF
September 13, 2022, 06:00:00 PM
post Re: Sources for optical parts?
[Light, Lasers and Optics]
klugesmith
September 13, 2022, 05:37:54 PM
post Re: Few questions before a TC show
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
September 13, 2022, 10:23:49 AM
post Re: The most powerful Russian Tesla coil in Europe (and maybe in the world)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
TeslaFX_rus
September 13, 2022, 09:59:45 AM
post Sources for optical parts?
[Light, Lasers and Optics]
Twospoons
September 13, 2022, 07:36:43 AM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 13, 2022, 03:43:58 AM
post Re: Circuit drawing software for dummies
[Printed Circuit Board]
LoOdaK
September 12, 2022, 09:45:41 PM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
mthome4
September 12, 2022, 08:09:42 PM
post Re: Circuit drawing software for dummies
[Printed Circuit Board]
Mads Barnkob
September 12, 2022, 04:34:54 PM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Maju
September 12, 2022, 04:32:03 PM
post Re: SSTC - PCB design
[Beginners]
Przemekk00
September 12, 2022, 03:00:32 PM
post Re: Circuit drawing software for dummies
[Printed Circuit Board]
LoOdaK
September 12, 2022, 02:26:47 PM
post Re: Circuit drawing software for dummies
[Printed Circuit Board]
Mads Barnkob
September 12, 2022, 01:09:53 PM
post Few questions before a TC show
[Dual Resonant Solid State Tesla coils (DRSSTC)]
AstRii
September 12, 2022, 12:52:58 PM
post Re: Circuit drawing software for dummies
[Printed Circuit Board]
Twospoons
September 12, 2022, 07:20:11 AM
post Re: Help with PLL induction heater driver
[Electronic Circuits]
petespaco
September 12, 2022, 04:48:21 AM
post Circuit drawing software for dummies
[Printed Circuit Board]
abstruse1
September 12, 2022, 03:33:52 AM
post Help with PLL induction heater driver
[Electronic Circuits]
dbach
September 12, 2022, 02:28:17 AM
post Re: QCW music with Midi
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyglas
September 11, 2022, 11:32:31 PM
post SALE(US) - 30 amp 3 phase GE volt-pac variac auto transformer 0-520v
[Sell / Buy / Trade]
pache11
September 11, 2022, 10:31:06 PM
post Re: Question about Flip-Flop wiring for DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
bockett
September 11, 2022, 10:28:43 PM
post Re: Question about Flip-Flop wiring for DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 11, 2022, 10:15:59 PM
post Re: UV-cured cyanoacrylate glues?
[Light, Lasers and Optics]
pache11
September 11, 2022, 10:05:44 PM
post Re: CO2 laser refurbishing
[Light, Lasers and Optics]
pache11
September 11, 2022, 09:57:35 PM
post Re: Question about Flip-Flop wiring for DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
bockett
September 11, 2022, 09:24:04 PM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 11, 2022, 09:19:30 PM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
mthome4
September 11, 2022, 07:39:19 PM

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