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Messages - davekni

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1
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I have measured whole bridge, all transistor's Gates and Collector to Emitter voltage.
All looks good.  If you want to scope the failure, I'd suggest adding a weak pull-up resistor to comparitor + input (instead of pull-down).  I suspect in the failed state one or more of the Vge signals will look wrong.

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It's been quite some time since I last scoped DRSSTC bridge, however isn't the bridge output looking kind of funny?
I have done these measurements at Vbus=70V and an iron pan as a load on the primary.
The sine-wave part of H-bridge output is on Vbus (on 70V supply when scoped at H-bridge).  It is caused by resonance of local bridge snubber caps and interconnect (wiring or bus bars) from there to bulk caps.  Looks like your resonance is between 1x and 2x coil frequency, so likely not causing trouble.  A few people on this forum have had the misfortune of this resonance being at or very close to 2x coil frequency.  Most bus ripple current is at 2x coil frequency.  This resonance voltage can build to +-Vbus, so double peak Vbus at H-bridge.  If your primary frequency drops enough due to arc loading and/or tuning, you could possible hit this unfortunate 2x ratio.

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This works as a charm! Thanks for the advice.. Before I test at higher power, may I know why do you not recommend this patch?
Patching an unknown issue always involves some risk.  The fault (cause of issue) may be stable.  If stable, patching is fine.  However, the issue might indicate other future issues.  A random example:  Suppose PLD programming was marginal and one bit has reverted states causing a logic change.  Patching works initially.  Eventually another marginally-charged internal PLD cell changes state.  This next failure might happen to be more catastrophic, destroying IGBTs or other circuitry.  (I don't recall experiencing this sort of PLD failure personally.  But I've used only three PLD part types over the past 30 years.)  Might be some other issue with UD+ board.  No way to know unless the failure is debugged and understood.

Good luck with either finding the issue or having it be stable so patching continues to work reliably.

BTW, you mentioned UD+ generating startup pulses.  If UD+ generates several (more than one) transition on gate signals before feedback starts, then no bleed resistor is needed across H-bridge outputs.  Of course, no harm in resistor other than a bit of wasted power.

2
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Hi Dave, I actually didn't have resistor on H-bridge output, however I added 22k resistor and the problem still persists. My MCC has 50nF, that's 1.1ms time constant together with 22k resistance. Should be quick enough for my roughly 100BPS@170us test.
I'd suggest scoping H-Bridge output.  Or at least measure voltages with a meter with Vbus applied and idle.  Perhaps one IGBT is slightly damaged and conducting slightly when "off".

If that shows nothing, will require more detailed testing.  Seems unlikely, but if gate driver for one side of GDT primary is not being disabled between interrupter pulses, I think that could explain symptoms.

Not what I'd recommend, but you could patch the issue with a weak pull-down (~100k) on + input of comparitor, forcing idle state low.

3
Unlike UD2.7, UD+ has no DC bias on FB comparitor input.  State between bursts is indeterminant.  I don't know UD+, but will presume the CPLD logic is similar enough to UD2.7.
Do you have a resistor across H-bridge outputs?  If not, bridge may be starting in same state as FB comparitor occasionally starts (high output).  Enabling then generates no startup transition on H-bridge.  I'd guess UD+ is working fine.  H-bridge output needs to start centered (0V differential) so that either polarity of initial half-cycle starts oscillation.

4
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But still there is a lot of parasitic inductance.
Presuming the back side of your H-bridge board is mostly covered in copper too, for the two bridge outputs, that is already good for low inductance.  Biggest remaining inductance is FET leads.  Forward recovery time of internal FET diodes contributes some to Vds spike voltage.  Some designs add an external fast diode in parallel with each FET drain-source.  However, your remaining very-short spikes are likely not problematic.

Quote
Interesting thing is that in zoomed out waveform of drain of Mosfet the transients disappears after some cycles.
Looking at your scope plot, looks to me like spikes are gone only after interrupter pulse ends.  Remaining time is TC primary current ringing down.  You could scope the interrupter signal or a gate to see.

Quote
Maybe I should also try phase shift secondary feedback a bit with capacitor and resistors like mentioned here:
No guarantee that it would help spikes.  However, there are other advantages to a self-oscillating circuit like you linked to.  I've posted similar self-oscillating alternatives in various threads.  Helps with startup, especially for ramped coils, as they need to start at low bus voltage.
BTW, looks like you may be using antenna feedback.  Self-oscillating is easy to add to antenna feedback, easier than for secondary current feedback.

5
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Although one thing I don't understand is that why we need a Vbus cap ? Wouldn't that smooth out AC ramps ? ( I'm sorry if I'm missing something here I'm using AC mains for my ramps )I didn't use any Vbus cap on half bridge either.
Large electrolytic bulk caps as used on normal non-ramped SSTCs and DRSSTCs would smooth out ramp.  Smaller ~0.47uF or 1uF film capacitors directly on H-bridge board are necessary.  They handle ripple from TC primary winding switching frequency (mostly at 2nd harmonic of that frequency).  Analog simulation (LTSpice or other) would be best for understanding this issue (and almost every other design detail).  For your half-bridge, the two caps used to split Vbus were apparently enough.  Usually there is at least one capacitor across Vbus besides the pair splitting Vbus for primary connection opposite FETs of half-bridge.  For full-bridge, at least one Vbus cap is needed.  Several small caps in parallel are even better as that reduces total cap lead inductance.  Mount cap(s) directly on foil between Vbus+ and Vbus-.

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I did notice for one mosfet rise and fall time was 50ns / 50ns . For the other one it was 50ns / 40ns something like that. I should have paid more attention to it.
Unlikely enough to be a problem.  Missing Vbus cap is almost certainly the cause of fried FETs.  (For learning, you could replace FETs and scope signals at 15Vbus before adding caps.)

6
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Mosfets I used in half bridge were IXTQ52N30P (listing said original disassembled parts) and I was able to get 7.5inch sparks.
That's a higher current part, presuming it was genuine.  Changing to full bridge and to lower current FETs makes for a likely issue.

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1) On time 1ms - 5ms@ 30Hz
I'd suggest testing at much lower repetition rate, such as 1Hz instead of 30Hz.  Gives more time for FETs to cool between bursts.

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2) I will try to etch my own PCBs. I have actually done it before. Thank you.
Focus on a good ground plane and very short connection from IC (especially driver chip) power pins to bypass capacitors.

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3) Also if power is not connected and I just supply oscillations from 555 timer. There is ticking sound (at whatever frequency interrupter is running) from somewhere
That's likely from GDT.  Without coil operating, GDT gets just low-frequency interrupter signal through coupling capacitor from driver to GDT.  Likely no issue.

Schematic shows no capacitor(s) from + to - bus voltage (Vbus+ to Vbus-).  If that is accurate, it is a problem and likely cause of FET failure.

7
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Also, I was short on mosfets and just used two IRF840 on positive side and two IRF740 on negative side. Could that be an issue?
Presuming genuine parts, specs are close enough, so not likely an issue.  For future when using mismatched pairs, I'd suggest using one part type for one half-bridge and other type for other half bridge (rather than + and - sides).  Then any mismatched switching times won't cause cross-conduction (shoot-through).

Quote
Or I was supposed to use TVS diodes or snubber RC circuit for it ?
Gate-source bidirectional TVS diodes are recommended.  But I'm guessing lack of TVS diodes isn't cause of your failure.

What line voltage are you using for the ramp?  What Vbus cap(s) are on the back side of H-bridge board?  What frequency is your SSTC?  What feedback are you using (circuit diagram)?
There are many possible causes for H-bridge failure.  Possibilities that come to mind for this case are:
1)  Higher current of full bridge is more than these FETs can handle for long on-time of a line half-cycle.
2) Higher load on driver board (four gates) is causing problems with driver board.  Hand-wired (breadboard) construction can be problematic, especially for the high peak currents of gate driver chips.  Using sockets for driver chips adds further to parasitic inductance and thus possible issues.

Good luck with repair and debug!

8
Vacuum Tube Tesla Coils (VTTC) / Re: Bigger sparks?...
« on: June 12, 2024, 03:32:22 AM »
Quote
I understand the resonance...But I wonder if the turn ratio of the coils wil result in a higher transformation in voltage and thus larger sparks?
Sparks might get larger or smaller.  Depends on how well coil load impedance matches GU50's drive capability.  Your GU50 circuit has an optimum load impedance determined by drive current and voltage.  If your TC has too high impedance now, lowering it will allow GU50 to transfer more power to coil.  If existing TC impedance is too low, then lowering it further will reduce power transfer.
I find it difficult to know ahead of time what impedance a given TC presents to a drive circuit.  If wire resistance were zero (ignored) and no arc present, then the primary impedance at a resonant frequencies is either zero or infinite.  Between resonant frequencies, impedance is purely reactive.  Arc resistance makes impedance non-zero and non-infinite at resonant frequencies.  Arc size affects impedance.  Impedance affects power transfer and therefore affects arc size.
Finding optimum is a matter of experiment.  You can get close by comparing other similar coil designs posted to this forum or elsewhere.

9
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I'm sure this is not a DRSSTC but then what is it ?
Yes, you changed your SSTC into a DRSSTC.  That's what "dual resonant" means.  Both primary and secondary are resonant.  Search the forum and/or elsewhere to learn about upper pole and lower pole (upper and lower resonant frequencies) of dual resonant systems.

10
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And Q1 was the issue. I actually saw your other posts also where you pinpoint issues with the circuit before the the original poster. Dammmm I super impressed. Hats Off.
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Glad to hear you got it working! Dave is the man!
Thank you both for the ego boost :)  Of course, don't take everything I post as absolute.  I do make mistakes.  Please feel free to question.

11
Quote
I would recommend using a 1:1 GDT for a better signal output.
Yes, definitely better.  Even better yet with two paralleled primary wires, one for each secondary:
    https://highvoltageforum.net/index.php?topic=1854.msg13949#msg13949

Quote
I had issues with my bridge because I thought I had bi directional TVS diodes but they weren't bi directional.
This circuit is using back-to-back zener diodes, which is effectively same as a single bidirectional diode.  Presuming zeners are correct voltage, that's not the issue here.  However, Vgs waveforms are asymmetric.  Wrong zener voltage would be one possible explanation, but not only one.

Quote
* q1_gate.jpeg
Much better to use scope probe in 10x mode.  1x mode probes have quite low bandwidth and high loading capacitance.  For 10x probing, do carefully adjust probe's compensation capacitor using scope's test square wave output.  Otherwise results are misleading.

This Vgs waveform is quite asymmetric and much lower voltage than would be expected given your schematic, roughly +5V to -10V.  If waveform looks similar after changing scope probe to 10x, I'd test again with all diodes removed.  No need for 30Vbus supply in that test.  Just check for an appropriate square wave.  Once GDT is 1:1, square wave should be close to +-12V, a but lower due to forward drop of driver chips.

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Drivers = UCC27321
You may want to consider adding schottky diodes on UCC27321 outputs, one to +12V and one to Gnd for each chip.  Many similar schematics include such.  UCC27321 and similar driver chips are intended for driving gates directly (through R/D), not for GDTs.  Added diodes handle reverse current (GDT magnetization current).  Less important if your GDT inductance is high (high permeability core) making magnetization current low.

Quote
* q2_gate.jpeg
This Vgs signal looks more like would be expected.  Voltage looks about right for a 1:1 GDT, however.  I'd have expected 1:1.5 to have boosted Vgs more.
Indicates issue may be with wrong zener voltage on Q1 or damaged Q1.
Slope on top and bottom of Vgs (which should be close to a square wave) isn't terrible, but more than ideal.  Could be due to load from bad Q1 circuit.  Or could be due to a low inductance GDT (low permeability core) or even a bad driver chip.  If fixing Q1 issue doesn't resolve this, I'd scope output of each driver chip and GDT primary after 1uF coupling cap.

Quote
* q2_gate.jpeg
Circuit layout looks good, especially half-bridge and GDT connections (nicely twisted and connected to FETs opposite high current S/D leads).
Breadboard construction of driver can sometimes be problematic due to lack of good ground plane and/or inductance between driver chips and their bypass caps.  However, I don't see any issues in scope traces that suggest driver board issues.

Quote
But weird thing is only Q1 gate resistor gets hot.
Yes, there appears to be some bad part or wrong value for Q2 or its gate components.

Good luck with debug!  May be as simple as fixing one fried or wrong-value zener for Q2.  Though I'd still recommend changing to a 1:1 GDT per tutorial link above.

12
Quote
There is still a gap since I have epoxy inside and an outer form but it is as close as it can get. Are you saying that the added inductor is effectively lowering the coupling by being included regardless of how close the primary is to the secondary?
Many factors affect coupling.  Close diameter increases coupling.  So does raising height of primary.  So does spreading out the primary turns vertically (even for the same center height).  Whatever your coupling may be before adding external inductor, that coupling will be reduced by adding the inductor.

Quote
I also think that by not having a large topload the coil is more easily detuned as the arc grows further assisting it getting to resonance in such a short window.
That may be a key way you stretch ramp time - by hitting optimum tuning near end when line voltage is starting to drop.

Quote
I do think that having the inductor allows me to more easily tune it since I can tap the coil or add and remove turns, while keeping the primary fixed. Seems to have been easier to manage vs rewinding the primary a thousand times like I have before.
Yes, adjustability is an advantage to added inductor.  Even just stretching its length suffices to adjust it (lower inductance).  You may need the resulting lower coupling in order to get the optimum ramp extension past 4ms.

Quote
So this is roughly what the bridge output looks like with the smaller 0.33uF caps. You can see it is more sinusoidal. With the 1uF caps the waveform was much more square, regardless of the MMC tuning. This was something that I noticed in my RSSTC. When I reduced the DC caps from 1uf to 0.3uF I had a large increase in output.
Yes, that's because bridge output now effectively includes part of MMC.  The half-bridge is still generating close to a square wave.  The other side has ~0.58uF (0.33uF in parallel with series of other 0.33uF in series with 1uF Vbus cap).  The sine wave contribution is from that passive side of bridge.  Sine wave current generating sine wave voltage across 0.58uF.


13
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Here is a video of what all of my tinkering has led to, solid 19in arcs @120v input with little branching.
Look great to me!  Though I don't have any directly comparable experience.

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Currently, I am still thinking that due to the short ramp time of ~8ms that mains ramped coils have to operate in, there is only so much that can be done to boost arc length at the cost of increased branching.
Yes, I'd agree.  In particular, ramp time is generally only 4ms or even a bit less.  Only 1/4th cycle of line voltage is increasing.  And even the last bit of that is rather flat.

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Ideal current ramp - Example from the video above
You have managed to stretch the ramp time to ~5ms!  Not sure just what combination of circuit parameters and arc loading effects causes this.  But it likely explains why your tuning is so specific and doesn't fit well to typical wisdom about ramped coils (such as being best with as high coupling as possible).

Quote
Smaller toploads seem to work much better. Even a large washer is sufficient.
Small top load combined with low coupling is unusual for a ramped coil.  Perhaps part of your achieving longer ramp time.
Larger top loads often require a longer and/or sharper breakout in order to start arc early enough during ramp.

Quote
Scope captures & findings: Blue = Bridge output (differential probe) Purple = primary CT with 51 ohm burden resistor
I'm guessing your CT is still 825:1.  Had to search back through thread to find that number.  Would be convenient to mention volts-to-amps conversion on scope traces of current.

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Quote
    An off-axis series inductor will lower the effective coupling, so that's something to bear in mind. It may not actually give you more secondary voltage, I'm not sure.
Do you mind elaborating a bit? Is proximity an issue or are you saying because it is simply in series with the primary?
Using random simple example numbers: a 1uH inductor in series with a 1uH primary is the same as a 2uH primary with sqrt(1/2) as much coupling.  You could achieve same result with a higher inductance lower coupling primary, such as a larger diameter 2-turn coil.
Higher coupling is generally better for ramped coils.  However, your specific case of stretching ramp to ~5ms will likely not hold if parameters are optimized in a conventional way.

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Here is a picture of the half bridge since I haven't shared one yet.
Looks good.

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I reduced the DC split rail caps from 1uF to 0.33uF, this improved output by a couple inches. Smaller DC split rail caps respond more quickly to changes in current, providing a more stable current output to the primary.
Split capacitors are in series with 94nF MMC.  Most significant effect of reducing them is to reduce effective MMC capacitance.  That tuning happens to work better for your coil.
Other perhaps-significant effect is to reduce total Vbus capacitance (1uF plus two split caps in series).  Vbus capacitance is charged to peak of line voltage (170V) at ramp start (unless discharged by a bleed resistor).  Don't see any initial spike at ramp start in your scope captures, however.

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My assumption is that the voltage doesn’t have time to ring up to such high levels compared to a traditional DRSSTC?
You have primary current measurement.  MMC voltage can be calculated based on current and frequency.

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OCD has not tripped with the half bridge.
Presuming 825:1 CT, 5.1V across 51ohms on current trace translates to 82.5A.

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Proposed solution: I plan on either using much more clearance around the mounting hole or mounting the PCB in another way.
For line voltage to ground, your existing screw with an insulating washer should be fine.  Presume mounting structure is grounded.
To minimize any unintended extra line-to-ground voltage at TC frequency, a small cap from line to Vbus- will bypass such higher frequency current.  ~5nF is typical, usually called a "Y cap" in power supply designs.

14
Spark Gap Tesla Coils (SGTC) / Re: Racing sparks
« on: June 02, 2024, 08:25:37 PM »
Quote
Javatc predicts that my coupling was .043k, but it couldn't see the actual geometry of the primary.
Yes, I've found some cases where JavaTC's drawing doesn't work.  Specifically, when some vertical positions are exactly 0.  Perhaps negative has same issue.  I'd guess drawing will work if you added a constant value to all vertical positions such that lowest position is slightly above 0.
Coupling value is likely still correct.  I'd expect a low value, so 0.043 seems reasonable for your geometry.

Hope your new build goes more smoothly!

15
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These pulses are very short and the max duty cycle overall will probably be around 5%, making the average current through the wire 7.5A. Average current is what dictates wire heating and what size wire is needed.
Correction to above:  RMS current dictates wire heating.  5% duty cycle reduces RMS current by sqrt(5%) = 22.4%.

16
Solid State Tesla Coils (SSTC) / Re: Steve Ward SSTC5 build
« on: May 30, 2024, 10:43:06 PM »
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I really couldn't understand why lower coupling made it worse.
Lower coupling requires more primary current to transfer same power to secondary.

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I don't really know what to make of the tight versus loose primary. I've seen both ways, loneoceans for example has the loose primary. Maybe the loose primary also needs more turns and that's why it didn't work for me.
I'd guess you need fewer turns (and associated much higher current) or higher bridge voltage (208 or full bridge) resulting in somewhat higher current.

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I feel like 10" sparks is pretty good for a 110v half bridge SSTC?
Yes, seems good to me.  Pushing this design may be fun, but also may result in dead FETs etc.

17
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Thanks Dave, I believe my relatively large toroid (1.3x secondary length), and high-ish coupling (0.162)
Yes, I'd guess those two are the most important factors.  Built my DRSSTC just before finding this forum.  Didn't have a good idea of what to target.  Great work!

18
Solid State Tesla Coils (SSTC) / Re: Steve Ward SSTC5 build
« on: May 30, 2024, 04:29:30 AM »
Quote
I thought they were bi directional TVS diodes but maybe they aren't, I'll check them out. The way they were hooked up should have worked right?
Connection is correct.  Though a bit better to have both TVS diode and GDT secondary solder to source lead close to FET body.
Looking closely at your picture, I can see a cathode indication band around one end of TVS diode.  That shows it is uni-directional.  Bi-directional TVS diodes don't have a cathode demarcation.

Quote
Thanks Dave, the 3 turn wire connected to the signal generator is floating and not grounded. I'll try scoping it the way you're saying though.
BTW, I'm surprised you got any feedback without connection to other end of 3-turn winding.  It is a current transformer (CT), so you need to drive it with current.  Driving with voltage as you did, only current is due to stray capacitance.  Doesn't matter now, however, since you have actual feedback working.

Quote
Something else interesting is I tried the blue secondary again and at full power it was pretty close to the green one except it blew the GFCI again. Now that I think about it it's only been the blue one that's blown the GFCI and never the green one. I have another higher current EMI filter, should I try it, or use both even?
Yes, I'd try both.  Difference may be just slight difference in operating frequency.  Line power wiring back to breaker may be resonating close to blue secondary frequency.  Also, adding a counterpoise under coil connected to ground (to secondary bottom after CT) will likely help.

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This also might explain why the blue one blows the GFCI, maybe the coupling is too low and I need to raise up the primary or add more turns.
Yes, GFI tripping may be due to sparks from secondary to primary.  Perhaps more likely than line wiring resonance as in my above paragraph guess.

Quote
What seems to have fixed the problems was going back to the thin insulation with the primary wrapped as tightly as possible then taped over.
Even if not sealed, tight may be OK.  If tight enough, air gap is so small, capacitance is high, so voltage across gap may be below corona threshold voltage.  I've seen tape as first layer over secondary as a way to get tight spacing, with tape adhesive filling in gaps.  But you may be fine even without adhesive against secondary given good tight construction.  Corona issues are most common with DRSSTCs using vertical primary windings, and with air gaps of a few mm.  SSTCs have a lower peak primary voltage, so less issue with corona there.
And, yes, SSTCs perform best with high coupling.  Larger primary diameter lowers coupling.

19
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I've got an interesting update now. The coil has hit 8.5 foot (2.6 meter) sparks! with a new toroid and the same tap point. I think it's around 10% detuning maybe a bit less, which still plays midi very nicely! These are video frames of an 8.5 foot ground strike! This is 3.7x the winding length while playing music which is amazing for a regular non pulse skipping DRSSTC!
Very impressive results!  Beautiful top load too.  (I rarely get more than 2m when tuned for good MIDI performance.)

20
Spark Gap Tesla Coils (SGTC) / Re: Racing sparks
« on: May 30, 2024, 03:47:12 AM »
Quote
If I back off the coupling any more (secondary windings start 3 1/2" above the primary), the streamers become intermittent, and yet the system still isn't 100% stable. Have I stumbled upon how to properly adjust coupling?
Quote
Your primary coil is more like a solenoid coil which will usually supply too much coupling for a disruptive (SGTC, DRSSTC) Tesla coil.
The tightly grouped primary windings make for low coupling.  3.5" below bottom of secondary further lowers coupling.  JavaTC results would be helpful to estimate actual coupling.  I expect it is below recommended for SGTC.
Perhaps short secondary is issue.  If you have any image captures (ie frame from video) showing "racing sparks", that would also help.
Yes, adjusting primary to secondary vertical distance is a common way to adjust coupling.

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post Van de Graaf Voltage measurement with voltage sensor and voltage divider
[Static Electricity]
vK
June 12, 2024, 03:42:18 AM
post Re: Bigger sparks?...
[Vacuum Tube Tesla Coils (VTTC)]
davekni
June 12, 2024, 03:32:22 AM
post Re: Bigger sparks?...
[Vacuum Tube Tesla Coils (VTTC)]
Teslaventje
June 11, 2024, 11:05:49 PM
post Re: Bigger sparks?...
[Vacuum Tube Tesla Coils (VTTC)]
MRMILSTAR
June 11, 2024, 05:36:46 AM
post Re: Sling Psychrometer
[Laboratories, Equipment and Tools]
Twospoons
June 11, 2024, 12:29:31 AM
post Bigger sparks?...
[Vacuum Tube Tesla Coils (VTTC)]
Teslaventje
June 10, 2024, 11:05:55 PM
post Re: Syntherrupter - A Feature-rich, Polyphonic Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
June 10, 2024, 10:57:51 PM
post Re: Benjamin's DRSSTC3
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
June 10, 2024, 08:08:04 PM
post Re: Plasma Torid - Class E Self Resonant Dual/Stereo - Plasma Torid Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hi-Deff
June 10, 2024, 06:04:09 PM
post Sling Psychrometer
[Laboratories, Equipment and Tools]
klugesmith
June 10, 2024, 04:43:59 PM
post Re: Benjamin's DRSSTC3
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
June 10, 2024, 03:35:28 PM
post Re: Benjamin's DRSSTC3
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Jj
June 10, 2024, 01:36:41 PM
post Re: Is a 60UF 800VDC Dawncap good for an induction heater?
[General Chat]
Anders Mikkelsen
June 09, 2024, 05:44:29 PM
post Is a 60UF 800VDC Dawncap good for an induction heater?
[General Chat]
yourboi
June 09, 2024, 03:31:30 PM
post Re: Steve Ward's DRSSTC Interrupter stops working when adjusting pulse width
[Dual Resonant Solid State Tesla coils (DRSSTC)]
NyaaX_X
June 09, 2024, 01:34:49 PM
post Steve Ward's DRSSTC Interrupter stops working when adjusting pulse width
[Dual Resonant Solid State Tesla coils (DRSSTC)]
verliebt_in_neukölln17
June 09, 2024, 01:56:51 AM
post Re: Return of Electronics Flea Market in "Silicon Valley"
[Sell / Buy / Trade]
klugesmith
June 08, 2024, 06:06:25 AM
post Re: Coulometric hourmeters
[Laboratories, Equipment and Tools]
klugesmith
June 08, 2024, 05:38:14 AM
post Interrupter for SSTC
[Beginners]
Simranjit
June 08, 2024, 12:47:47 AM
post Re: Adding capacitor to primary in SSTC
[Solid State Tesla Coils (SSTC)]
Michelle_
June 07, 2024, 03:59:57 PM
post Re: Adding capacitor to primary in SSTC
[Solid State Tesla Coils (SSTC)]
davekni
June 07, 2024, 06:42:26 AM
post Re: Space-X Starship test this week
[Science, Research and News In Other Fields Than Electronics]
MRMILSTAR
June 07, 2024, 05:08:00 AM
post Re: Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
davekni
June 07, 2024, 03:16:31 AM
post Re: Space-X Starship test this week
[Science, Research and News In Other Fields Than Electronics]
klugesmith
June 06, 2024, 11:37:20 PM
post Adding capacitor to primary in SSTC
[Solid State Tesla Coils (SSTC)]
Simranjit
June 06, 2024, 11:20:23 PM
post Re: Plasma Torid - Class E Self Resonant Dual/Stereo - Plasma Torid Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
June 06, 2024, 10:54:48 PM
post Re: Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
ZakW
June 06, 2024, 05:17:02 AM
post Re: Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
Simranjit
June 06, 2024, 04:50:00 AM
post Re: Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
davekni
June 06, 2024, 04:00:52 AM
post Re: Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
ZakW
June 06, 2024, 01:43:41 AM
post Re: Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
Simranjit
June 05, 2024, 11:11:17 PM
post Re: Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
Michelle_
June 05, 2024, 10:18:57 PM
post Re: Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
Simranjit
June 05, 2024, 10:13:03 PM
post Re: Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
ZakW
June 05, 2024, 09:29:18 PM
post Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
Simranjit
June 05, 2024, 08:46:53 PM
post Re: Want to build HV HF oscilloscope probe.
[Electronic Circuits]
Twospoons
June 05, 2024, 07:04:45 AM
post Re: Want to build HV HF oscilloscope probe.
[Electronic Circuits]
Domo
June 05, 2024, 04:58:35 AM
post Re: Pearson current monitor model 1330 teardown (100kA)
[Laboratories, Equipment and Tools]
klugesmith
June 05, 2024, 01:42:04 AM
post Re: Coulometric hourmeters
[Laboratories, Equipment and Tools]
klugesmith
June 04, 2024, 10:31:58 PM
post Re: My completed 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
pete_dl
June 04, 2024, 08:08:28 PM
post Re: Want to build HV HF oscilloscope probe.
[Electronic Circuits]
Twospoons
June 03, 2024, 11:13:26 PM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
June 03, 2024, 10:35:57 PM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hi-Deff
June 03, 2024, 05:51:05 PM
post Re: Want to build HV HF oscilloscope probe.
[Electronic Circuits]
Domo
June 03, 2024, 07:41:41 AM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
June 03, 2024, 05:28:44 AM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 03, 2024, 05:02:19 AM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
June 03, 2024, 03:47:33 AM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
June 03, 2024, 02:23:58 AM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hi-Deff
June 03, 2024, 01:25:24 AM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
June 03, 2024, 01:08:47 AM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 02, 2024, 10:29:02 PM
post Re: Steve Ward SSTC5 build
[Solid State Tesla Coils (SSTC)]
Michelle_
June 02, 2024, 10:02:45 PM
post Re: Racing sparks
[Spark Gap Tesla Coils (SGTC)]
davekni
June 02, 2024, 08:25:37 PM
post Re: Steve Ward SSTC5 build
[Solid State Tesla Coils (SSTC)]
Michelle_
June 02, 2024, 04:51:58 PM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Michelle_
June 02, 2024, 04:44:30 PM
post Re: My completed 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
MRMILSTAR
June 02, 2024, 03:25:11 PM
post APC Smart-UPS 1500VA Teardown
[Electronic Circuits]
Mads Barnkob
June 02, 2024, 01:36:11 PM
post Re: My completed 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
pete_dl
June 02, 2024, 11:43:40 AM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
June 02, 2024, 08:49:11 AM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
June 02, 2024, 08:36:07 AM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
June 02, 2024, 12:41:50 AM
post Re: Steve Ward SSTC5 build
[Solid State Tesla Coils (SSTC)]
Benjamin Lockhart
June 01, 2024, 08:24:35 PM
post Pearson current monitor model 1330 teardown (100kA)
[Laboratories, Equipment and Tools]
Mads Barnkob
June 01, 2024, 08:22:28 PM
post Re: Steve Ward SSTC5 build
[Solid State Tesla Coils (SSTC)]
Michelle_
June 01, 2024, 03:56:53 AM
post Re: Racing sparks
[Spark Gap Tesla Coils (SGTC)]
Terry
June 01, 2024, 12:03:50 AM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hi-Deff
May 31, 2024, 11:46:20 PM
post Re: Steve Ward SSTC5 build
[Solid State Tesla Coils (SSTC)]
Michelle_
May 31, 2024, 06:13:59 PM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
May 31, 2024, 01:55:22 AM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
May 30, 2024, 11:57:49 PM

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