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Messages - davekni

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21
Dual Resonant Solid State Tesla coils (DRSSTC) / Re: UD2.7C Debugging
« on: March 05, 2024, 05:18:28 AM »
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The mosfet Q4 irfp540 keeps dying (2 have died so far).
One likely cause for IRFP540 dying is that the paired IRF9540 is failed shorted.  Or that 1k gate pull-up resistor(s) are open (ie. bad solder joint) or 0.1uF coupling capacitor is shorted.

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Even the time in which it is on, the gate drive output waveform doesn't look good and it keeps moving.
Scope traces of the two GDT primary leads (UD2.7 output terminals) would be more useful for debug.

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It still tends to turns off after a few seconds of operation, also the LM7812 voltage regulator gets extremely hot.
Output FETs don't directly connect to +12V, only UCC27423.  Since it is still good, implies high load on UCC27423 output(s).  Most likely cause is a bad FET with shorted gate.  Another reason to suspect an IRF9540 having died (or both).

If still problematic, I'd remove all four FETs and test with UCC27423 chip installed.  Scope FET gate waveforms and verify supplies are not loaded excessively.

22
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The partition of RF current might depend a lot on the inductance of wires.
Exactly what I was thinking, why I guessed wire size was not an issue.

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Inductance depends on log of (wire spacing / wire diameter), but the empirical formulas are less accurate when the insulation is much thinner than the conductors.
Very rough estimates should be fine here.  Physical layout prevents twisting for  ~half of wire length anyway.

Just looking at existing wiring, I'd guess between 0.6uH and 1uH for wires.  At 40kHz coil, ripple current is 80kHz.  0.6uH is ~0.3 ohms reactance at 80kHz.  560uF capacitor at bridge is ~0.0036 ohms.  Thus very little 80kHz current will flow through wires.  Interconnect inductance of 560uH capacitor is likely higher than 0.0036 ohms, so may control wire current more than capacitance.

Edit:  Forgot about pulse-skipping.  That will generate lower frequency ripple current.  At 20kHz, current sharing would be closer to 5:1.  But I think RMS current component at 20kHz will be lower than 80kHz of full-on operation.  Would need to simulate or hand-calculate a bit more to be sure of this.

The biggest risk may be if pulse-skipping frequency happens to hit exactly at LC resonant frequency of 560uF and wire inductance.  That's where some form of R+C snubbing might be needed at bridge.

23
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Input is designed for 240v 30A 3ph, but would run fine on single phase or even a dc source like an EV battery.
That is a very unusual voltage to find in US.  Usually 3ph is either 208V phase-to-phase (120V phase-to-neutral), or 480V (277V to neutral).

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The capacitor directly on the bus is a 560uF electronicon dc link capacitor. I'd hoped it would take most of the resonant current, but I'll probably switch the red wires to 2x 4awg twisted together for less inductance.
Less inductance is good.  I'd agree that 560uF will handle resonant current.  2x wires are likely unnecessary.

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There are 1k resistors between G-E of each igbt, so when I turn off the GDT signal, all IGBTs should turn off. I'll probably be running within the datasheet current limit. When I added that contactor, if I turned off AC it would be a few seconds before the UD went into UVLO. I've since added fans on the same power supply that draw 2.5 amps so the UD goes into UVLO very quickly, so I think the contactor may be unnecessary. I just wanted to make sure the arc would shut off as soon as I pressed the estop.
1k is unlikely to be stiff enough (low enough resistance) to keep Vge below threshold.  Remaining GDT magnetization current will be a problem, as will gate charge caused by Vcg swings and Ccg as primary current rings down.  IGBTs might or might not survive.  I'd remove GDT contactor.

24
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What are you saying about increasing the field beyond 2T? Do you mean specifically certain materials such as cobalt, or is there a way to utilize >1T in iron/steel that I don’t know about yet?
Typical low-carbon steel such as 1018 very-hard saturation is slightly above 2T, why I used that as an example.  Saturation describes the limit of polarization a material can achieve.  It is not a limit on magnetic field.  Beyond saturation, relative permeability approaches 1, same as air.  For example, an applied H field from a coil of 4e6 A/m will generate 5T B field in air.  In 1018 steel, that same 4e6 A/m H field will generate 7T B field, 2T higher.

25
Electronic Circuits / Re: CM400 Induction Heater
« on: March 03, 2024, 08:01:42 PM »
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Your GDT buffer circuit looks nice, but if needed I will try to get the IXYS gate drivers to work since I already have them. The nice thing with these is that they run from a single 15V supply and derive their isolated supplies themselves. I will keep it in mind though for future projects!
The IXYS gate drivers should work well.  My GDT buffer does not require any external power.  Vge rising edge is provided by GDT secondary.  No buffering on rising edge.  Falling edge is pulled to 0V with local FET.  Requires no extra power supply.  Makes falling edge faster and limits Vge to 0V rather than negative.  Latter change reduces required gate drive power due to 0V minimum.  Theoretically to 25% (down by 75%), but about 30% in practice.  Even though unbuffered, rising edges are a bit faster because other GDT secondary windings (ones turning off) are only lightly loaded.

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I meant that with large tank capacitor current ringup will be very fast, making it harder to precisely set your desired current limit with an OCD (kinda like a super low impedance DRSSTC). It might not matter that much since we do not go for extreme currents anyways.
Thank you for the explanation.  Makes sense.

Good luck with your project.

26
Quote
-cat5 for GDTs is prone to flashing over with high bus voltages. cat6 is much less so due to the plastic barrier between wire colors.
Usually each twisted pair is split, half primary and half secondary.  That minimizes parasitic leakage inductance.  Grouping wires to take advantage of plastic barrier for voltage will increase leakage inductance.  Added inductance may be OK for a low frequency coil.

BTW, what is your line voltage input?  240Vac single phase?   Or do you have access to three-phase?

27
Electronic Circuits / Re: CM400 Induction Heater
« on: March 02, 2024, 10:19:09 PM »
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I tried removing the TVS since some people reported similar issues resulting from their added capacitance, but could not perceive any improvement.
These ~600W TVS diodes typically have ~1nF capacitance, insignificant compared to Cge.

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Any tips for how I can achieve CW operation without melting my gate resistors? So far this is the most pressing issue for me. Is it normal that they get that hot?
Could the long wires be an issue (I did not cut them since they are supposed to go into my DRSSTC project), would lowering the gate resistance be enough, or maybe lowering the voltage to something like 15V?
Driving a brick CW requires a lot of gate power.  Yes, hot resistors is normal.
Lowering to +-15V will help by (15/20)^2, cutting power almost in half.  Even at +-15V, there is ~4.6W to dissipate (5uC * 30V * 31kHz).  Lower resistance does not change that 4.6W total.  If low enough, will push some of that power back into UD+ output FETs.  And 2.8 ohms is already under spec'ed minimum external resistance of 3.1 ohms.  Likely doesn't matter for low bus voltage.
Long wires (high GDT leakage inductance) increases gate power only if high enough to cause Vge overshoot.  Scope waveforms show no issue there.

I'd suggest lowering to +-15V and accepting 4.6W (using more or larger resistors).  Another option is to reduce to +15/-0V (or +20/-0V) with something like this circuit on GDT secondaries:
    https://highvoltageforum.net/index.php?topic=2389.msg17547#msg17547

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How far do you think I can push the Wima MMC? Right now with 60p = 13.2uF the MMC is rated for 168Arms.
Since this isn't going to run 24/7, I'd push caps.  Might get away with 2x RMS rating if caps are spaced out a bit for air flow and fans added.

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Downside of the large capacity is that it makes current regulation more difficult
Why is current regulation more difficult?


28
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Something I’ve found out about the induction guns which is obvious if you think about it, the radial reaction force puts a huge strain on the coils so they require mechanical reinforcement as to not fatigue and short. Sandia labs actually has a paper on this, it sounds possible to make them reliable but it will be extra work for sure.
Yes, that is why I mentioned coil explosion hazard.  For coin shrinking, every version I've seen just allows coil to explode.  A new coil is wound for each coin.
There is a company called Maxwell Magneform that makes reinforced coils for magnetic forming and welding.  Don't know how such is accomplished.

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I’ve decided to build a reluctance coil gun as well because I’ve accidentally learned how they work through researching the induction guns, and I feel like I could build a more reliable one to mess around with and try making portable.
Certainly easier for experimenting.  Reluctance can be pushed beyond 2T projectile saturation, but efficiency drops faster as field increases.  For eddy current launchers, doubling field requires 4x input energy and provides 4x output energy.  For a reluctance launcher beyond saturation, 2x field still requires 4x input energy, but provides only 2x output energy.

29
Responding to FPS' question
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Why couldn't you slide the disk over a solid "barrel" made of ferrite or perhaps a metal rod cluster and use the accellerated disk as a form of sabot to drive a dart that is also slipped over the "barrel" in front of disk.
Certainly possible in some form.  However, requires mechanical strength (ie. cone shape) to take force from disk to smaller diameter dart.  Otherwise disk folds over from force.  Weight of entire assembly (disk, cone, and dart) must be accelerated, reducing efficiency.

30
Solid State Tesla Coils (SSTC) / Re: Gate Driver Waveform, Puzzled
« on: March 01, 2024, 03:26:16 AM »
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I may tear the whole thing apart and see if some bonehead mistake shows up.
That's certainly one option.  My strategy would be more scoping, perhaps with some simulation too.  Waveforms that are so far from expected can make debug easier.  If waveforms are close but not quite right, the issue is likely more subtle and hard to find.

My first thought is to zoom into Vds waveform.  Does it appear to clamp at +200V?  Is the FET the wrong part, a 200V part?  Or the diode something that is breaking down at 200V?  Also zoom into low voltage part of Vds to see what parts look like FET on-state and which parts are diode conduction (-0.7V or so).  Of course, current through FET would be very helpful to know, but difficult to measure without adding excess parasitic inductance.

31
Glad you are finding lots of information.  Yes, I do find Russian posts or videos of very high power DIY projects, such as a 28kW RF Tesla coil making 1m+ high plasma flame running in a bedroom.  Fed by a radio transmitter tube.

Also, I realized I was making one key bad simplification in analyzing that "500m/s" paper.  I was calculating L/R time constant for the entire projectile in free space, not for each pole piece segment in close proximity to a copper coil.  Then I looked back at the paper and found I'd recalled a couple key parameters wrong too.  So I retract my thought about it being an inherently inefficient design.  Especially the initial theoretical design looks relatively good.  Once build realities changed coil gap and speed for their prototype, I'd still guess a couple other changes would be helpful to match.  Guessing a bit longer pole pitch to track gap and lower frequencies to track both pole pitch increase and speed reduction.  Might get a bit more speed out of real construction.

Have fun reading!  This has been an interesting conversation.  Intrigued me enough to think deeper than I'd planned.  Was a fun exercise in electromagnetics.  I'll be interested to learn what you end up designing.  In the mean time I'm focusing back on the projects I'm in the middle of.

32
Electronic Circuits / Re: Op-amp amplification of offset input signal
« on: February 29, 2024, 02:32:12 AM »
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I suppose one option is to pick something with a much lower input bias and I see there are many options on Digikey.
Yes, there are many opamp options with infinitesimal bias current (FET input stage).  Especially for rail-to-rail, BJT input stages are rare.  Only very high speed opamps (and some high-power opamps) tend to have BJT input stages these days.

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I also found this resource: https://www.analog.com/media/en/training-seminars/tutorials/MT-038.pdf.  Following the advice in figure 3, I added a 9090 ohm resistor in series with my offset supply (connected to the positive input) and this worked!  Output is nicely centered around 1VDC. 
Be careful here.  This was a common solution for older non-rail-to-rail BJT input opamps where bias current was much higher than offset current.  Cancels out bias current, but not offset current.  Newer BJT input opamps such as AD8029 often cancel out nominal bias current internally.  So offset current can be as high as bias current, which is the case I think for this part.  Model happens to have 0 offset current, but real world could end up above or below 1V output.  Better to change opamp, or reduce resistor values so that bias/offset current translates to less voltage.

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Thank you Dave!
You're welcome!  Glad to be useful sometimes.

33
Electronic Circuits / Re: Op-amp amplification of offset input signal
« on: February 28, 2024, 07:32:10 PM »
Quote
What am I missing here?
AD8029 input bias current is causing your puzzle.  For future reference, you can probe currents into circuit elements.  Pretend I didn't give away the answer in first sentence.  Here's what I'd do to debug such an issue:  First probe the two opamp input pins to verify that they are close to the same voltage, 1.00Vdc in your case.  Then probe the currents through R1 and R2.  With an ideal opamp, R1 and R2 currents must match because opamp input current is ideally zero.  When you find that R1 and R2 currents are not equal, then probe opamp - input current.  You'll find it is the difference between R1 and R2 currents, as the sum of all currents into a circuit node must be zero.

34
Solid State Tesla Coils (SSTC) / Re: Gate Driver Waveform, Puzzled
« on: February 28, 2024, 06:23:57 AM »
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I'm getting some small sparking from the coil. But another waveform is again giving me a puzzle.
That is a puzzle.  My best guess is that coil is locking to 2nd harmonic of drive frequency.  Not at all certain.  Looks like drive is running at ~600kHz and coil resonant frequency is ~1200kHz.  Perhaps reverse TC primary leads to invert phase.

35
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At any rate I had an idea about using a pusher for the first acceleration phase from V0 as to not waste an entire three phase stage on that acceleration. Then firing the pushed projectile into the polyphase bank.
Would get projectile moving faster initially.  However, does not provide for magnetic field penetration of projectile wall in the pattern used for LIM.  That might not matter in the simple two-stage version.  I'm not sure if that design matches phase well enough as projectile moves from first to second stage.  If not, initial magnetic field within projectile will not be useful to second stage.

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Last thing right now is I found out about SiC MOSFETS
SiC FETs (MOS or junction) are used by high-end Tesla coil builders, especially for coils above ~300kHz.  FET pulsed current capability (including SiC) is much lower than for IGBTs, so not a good choice for your use.  BTW, the one SiC thyristor that theoretically can be purchased has fast turn-off, but not very high current (80A max) and is very expensive ($3000 each with minimum 10 order).

There are a few thyristors I've found that are designed for pulsed power, with a few that can be purchased:
Y500CNC250  50kA peak, 2500V, 11A/ns  ~$1200 from electronics distribution, but long lead time.
PT40QPx45    13kA peak, 4500V, 5A/ns    ~$100 on EBay
PT85QWx45  37kA peak, 4500V, 22A/ns   ~$700 on EBay

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Oh yeah and there's this gem which I wish I found a long time ago: "In the design of a linear induction launcher (LIL), the synchronous speed should ideally be higher than the desired projectile speed. This is because the slip, which is the difference between the synchronous speed and the actual speed of the projectile, represents the mechanism by which the launcher imparts kinetic energy to the projectile." the 500m/s launcher had a critical slip specified at 15% and 500m/s.
This view works well once magnetic field penetrates projectile and presuming phase is matched from stage to stage.  At start speed is 0, so 15% of 0 is 0.  Starting is the complex part for LIM, but that's the entire length for short low-stage-count designs.  If each pole is it's own stage and frequency of each stage could change over time (instead of simple ring-down waveform), even short LIMs could theoretically be efficient (I think).  That way there could be smooth transitions from stage to stage.  Stages are shorter than projectile so could be optimized as projectile travels through stage.  At the higher velocity (later) end of a LIM, stages could be longer.  Duration within each stage is shorter at high speed.

In general, coil magnetic field wants to be some ideal phase ahead of projectile magnetic field.  Typically (for normal induction motors at least), maintaining that constant phase requires a constant slip speed, not a function of motor speed.  (Of course, most induction motors run at fixed speed, so it doesn't matter if slip is defined as a percentage or absolute speed.)  Perhaps that is why slip percentage is specified at exit velocity.  For high power LIMs, projectile will heat as it travels, increasing electrical resistance.  That will increase ideal slip for later stages.  Perhaps not a concern for your smaller designs.

36
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Is it safe to use the projectile to trigger spark gaps?
That's an interesting idea that might function well, though probably needs a ceramic launch tube to withstand spark heat.  Can't think of any new safety concerns, as I presume the entire launch assembly needs to be enclosed in something to prevent user contact.  Oh, another possible issue is metal vapor deposits on ceramic tube eventually creating a conductive path.  Spark gaps usually avoid having insulation immediately adjacent spark path.
Perhaps projectile could trigger a small spark that in turn triggers the real power-switching spark gap, perhaps through a trigger transformer.

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Garolite G10 (can I use this?)
Looks fine to me.

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I’m also thinking about risk analysis and this is almost too dangerous imo, especially since thinking about holding it next to your face.
I see three key risks:
1) High voltage shock hazard
2) Explosion of coils due to magnetic force (as happens every shot of my quarter shrinker)
3) Explosion due to unintended short circuit of charged caps.
For 1, proper insulated housing should mitigate this risk well.
For 2, I don't have enough mechanical skills or knowledge to say just what would be safe.
For 3, hearing loss might be the biggest risk based on personal experience.  I had some hearing loss for months (and likely never completely recovered) due to accidentally shorting a large electrolytic cap I was testing in front of me.  Beyond that, any shielding that can handle (2) is likely sufficient.

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I don’t know what to do about this besides scale down to a small version which is still dangerous but I might have a shot at making shielding, maybe out of Kevlar composite, I don’t know yet.
Not my area of expertise, but I'd think you want a housing optimized for impact strength such as polycarbonate.  Kevlar is strong, but not stretchy, so can't absorb as much impact energy.  Would be a good material around coils to handle expansion force.  There you do not want any stretch as stretch would allow coil to deform.  UHMWPE is strong and I think a bit better than Kevlar for impact strength.  Not sure.

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For now I’m considering walking back some of my goals and starting with a maximum projectile mass of .25g-.5g and simulating a single coil discharge, as recommended.
Tiny is hard.  Efficiency doesn't scale well even if gaps could be scaled down.  Larger coil to projectile gap (proportionately) makes efficiency even worse.

Especially for your smaller (but I'd stay above 1g if I were you) design especially, I think IGBTs are the optimum choice.  I looked up a few parts for you using DigiKey search.  For best price on any of these, check oemstrade.com.
IKY75N120CS6,  1200V 300A peak.  Cheapest option for initial experiments.
IXGK75N170,      1700V 580A peak.
IXBF55N300,       3000V 600A peak.
IXBX50N360HV   3600V 420A peak.
FZ400R65KE3NOSA1 6500V 800A, very expensive option to use only if needing more than 3600V.
All except the final one are in TO247 variant packages, ~5mm thick.  Stacking an array of these in parallel is relatively easy presuming you have ability to design ECBs.

Finally, I've been thinking more about that "500m/s" linear motor paper that really achieved 150-250m/s.  My intuition now says that is not at all an efficient design worth copying.  Projectile is only 4 poles long, not even one full cycle of 6 poles, and it has only two stages.  I think linear motors will be more efficient only when projectile is at least one cycle long (6 poles of 3 phase) or much more and with more stages, at least 5 or 6.  Until that level, a pusher is likely more efficient.  Linear motors take time to start as magnetic field must penetrate projectile before thrust is generated.  Before that force is all radially inward (as in the projectile crushing issue in above paper).  Optimum starting requires low initial frequency of first stage that then ramps up in frequency as projectile moves.  On the other hand, a pusher provides maximum force initially as it relies on projectile blocking magnetic field.  For a pusher, frequency must be high enough that field reverses before too much has penetrated projectile.

37
Quote
Do you have a clue where to look first if its not oscillating at all?
Could be that secondary is needed for oscillation.  Or there may be an issue with construction/layout, excessive parasitic interconnect inductance.  Or part selection (ie. cap with excess ESR).

38
Solid State Tesla Coils (SSTC) / Re: Gate Driver Waveform, Puzzled
« on: February 27, 2024, 04:16:43 AM »
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Is the UCC37322 seeing this indeterminate voltage as a signal an "pushing"  it through during the interrupter pulse?
Yes, that is the way it is intended to work (I think).  The lead edge should start oscillation.  However, your GDT is reversed.  Initial pulse should be positive on gate rather than negative.

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I can try the smaller capacitor but the 1 uF (it's actually 2uF one on each side of the gate drive chip)
is what I've used in a few other designs and has worked great.
Even once you fix GDT connection polarity, that circuit will create a low frequency ring on Vgs.  An artifact of circuit's simplicity.  A smaller capacitor would probably be better for this design, as would some form of simple diode+zener clamp to keep GDT primary from swinging below -6V (to damp out ring quickly).

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The only difference with my coil and the schematic shown is I'm using an UCC37322.
There is a significant difference.  Original part has typical input threshold at slightly under half supply, ~5.5V for 12V supply.  UCC37322 has input threshold around 2V.  Input clamp diode leakage current biases input to ~6V (half supply).  Requires more feedback signal to start oscillation from 6V down to 2V.  Appears you have enough feedback signal, so that part may be OK.  Original design would have a problem if either UCC27519 input threshold happened to be >6V (within spec range) or input diode leakage currents don't match making quiescent voltage <5.5V.

39
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Does this mean my bricks are actually not that bad after all (at least not worse than a Powerex CM200 for example)?
Also depends on diode Vf and IGBT Vce, switching losses, and max allowed temperature (sometimes 150C and sometimes 175C).  Vf and Vce and other losses matter at max temperature.  Transient thermal impedance is important too unless duty cycle is very high.

40
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Is there anyy reason not to use an ignitron?
I don't know enough about ignitrons to say.  If you can find ones for your needed voltage and current after scaling, probably fine.  I don't think ignitrons are common devices around today, but don't really know.

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I think your pusher design is good and the spark gap idea is good. In fact I found something you might be interested in:

https://www.rapp-instruments.de/index6.htm

Click on induktion gun 2. This seems more like what you're describing. Admittedly maybe I should look more into this as an alternative but I would still really like to build the polyphase style launcher, if I can learn enough to pull it off.
Yes, from a quick look it is probably a 6-stage pusher design.  (I learned some German 50 years ago.  Was never fluent, and lost most of what I knew.  Not taking time to run it through Google translate.)

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I'm assuming the polyphase gun is more efficient, which I don't know for a fact.
I think it is for projectiles with high (normal) aspect ratio (longer than diameter).  Also most useful with multi-stage launchers where projectile current builds up, though I haven't thought through this bit in detail.

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[General Chat]
davekni
March 14, 2024, 11:23:20 PM
post Re: Bleeder resistor for MMC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
March 14, 2024, 09:32:27 PM
post Difference between these transformers
[Transformer (Ferrite Core)]
Alberto
March 14, 2024, 09:29:06 PM
post Re: Bleeder resistor for MMC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Keybored
March 14, 2024, 09:11:54 PM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
WolfMoonshirt
March 14, 2024, 06:09:27 PM
post Re: No Corona Discharge with ZVS Driver
[Beginners]
MaybeJosh
March 14, 2024, 01:36:35 PM
post Re: No Corona Discharge with ZVS Driver
[Beginners]
MaybeJosh
March 14, 2024, 11:43:23 AM
post Re: Super flat QCW simulation (does this look reasonable?)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 14, 2024, 05:03:41 AM
post Re: No Corona Discharge with ZVS Driver
[Beginners]
davekni
March 14, 2024, 04:56:51 AM
post Re: Bleeder resistor for MMC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 14, 2024, 03:09:45 AM
post Re: Bleeder resistor for MMC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
AstRii
March 14, 2024, 02:23:11 AM
post Bleeder resistor for MMC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Keybored
March 14, 2024, 01:02:32 AM
post Re: Art student Need help with Plasma Toroid
[Beginners]
toooldforthis
March 14, 2024, 12:01:55 AM
post Re: Art student Need help with Plasma Toroid
[Beginners]
alan sailer
March 13, 2024, 10:22:58 PM
post Re: Simple oscillator instead a ZVS
[Transformer (Ferrite Core)]
Alberto
March 13, 2024, 09:31:22 PM
post Re: Super flat QCW simulation (does this look reasonable?)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
toooldforthis
March 13, 2024, 07:04:35 PM
post Re: Simple oscillator instead a ZVS
[Transformer (Ferrite Core)]
Twospoons
March 12, 2024, 11:55:37 PM
post Re: Simple oscillator instead a ZVS
[Transformer (Ferrite Core)]
Alberto
March 12, 2024, 10:10:41 PM
post Re: Electric insulator. Paraffin wax?
[General Chat]
Alberto
March 12, 2024, 10:08:51 PM
post No Corona Discharge with ZVS Driver
[Beginners]
MaybeJosh
March 12, 2024, 09:13:00 PM
post Re: Anyone know of a good variable driver?
[Beginners]
FPS
March 12, 2024, 06:54:50 PM
post Art student Need help with Plasma Toroid
[Beginners]
lovejdz
March 12, 2024, 11:12:01 AM
post Re: Electric insulator. Paraffin wax?
[General Chat]
Twospoons
March 12, 2024, 01:16:48 AM
post Re: Simple oscillator instead a ZVS
[Transformer (Ferrite Core)]
Twospoons
March 12, 2024, 01:14:35 AM
post Re: New type of hfsstc using self-oscillating current mode class D
[Solid State Tesla Coils (SSTC)]
Perolodzilla
March 11, 2024, 04:18:50 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
TMaxElectronics
March 11, 2024, 12:50:34 PM
post Re: Electric insulator. Paraffin wax?
[General Chat]
Alberto
March 11, 2024, 08:32:09 AM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 11, 2024, 05:01:03 AM
post Re: Electric insulator. Paraffin wax?
[General Chat]
MRMILSTAR
March 11, 2024, 04:23:20 AM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
March 11, 2024, 02:30:11 AM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
TMaxElectronics
March 11, 2024, 12:37:52 AM
post Electric insulator. Paraffin wax?
[General Chat]
Alberto
March 10, 2024, 11:06:04 PM
post Re: Bleeder resistor in CW multiplier
[Voltage Multipliers]
davekni
March 10, 2024, 06:58:51 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 10, 2024, 06:49:36 PM
post Bleeder resistor in CW multiplier
[Voltage Multipliers]
Sugarb0y
March 10, 2024, 05:37:39 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
March 10, 2024, 02:16:25 PM
post Re: Simple oscillator instead a ZVS
[Transformer (Ferrite Core)]
Alberto
March 10, 2024, 02:01:12 PM
post New type of hfsstc using self-oscillating current mode class D
[Solid State Tesla Coils (SSTC)]
Perolodzilla
March 10, 2024, 01:03:51 PM
post Re: [WTS] IGBT, Ferrite, Capacitors, Tools, PSU, Industrial components and parts
[Sell / Buy / Trade]
Mads Barnkob
March 10, 2024, 10:16:38 AM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 10, 2024, 07:10:22 AM
post Re: Simple oscillator instead a ZVS
[Transformer (Ferrite Core)]
MRMILSTAR
March 10, 2024, 05:18:03 AM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
March 10, 2024, 04:50:13 AM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 10, 2024, 03:42:28 AM
post Re: Simple oscillator instead a ZVS
[Transformer (Ferrite Core)]
Twospoons
March 10, 2024, 12:05:09 AM
post DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
March 09, 2024, 10:40:11 PM
post Simple oscillator instead a ZVS
[Transformer (Ferrite Core)]
Alberto
March 08, 2024, 10:49:24 PM
post Re: Frequency
[Transformer (Ferrite Core)]
Alberto
March 08, 2024, 10:22:59 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
March 08, 2024, 08:22:34 PM
post APC Smart UPS 450 Watt, for Server 19" Rack 1U, Teardown
[Electronic Circuits]
Mads Barnkob
March 08, 2024, 04:07:44 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Late
March 08, 2024, 11:56:11 AM
post Re: CM400 Induction Heater
[Electronic Circuits]
petespaco
March 08, 2024, 01:59:43 AM
post Re: Frequency
[Transformer (Ferrite Core)]
davekni
March 07, 2024, 11:35:01 PM
post Re: Frequency
[Transformer (Ferrite Core)]
Alberto
March 07, 2024, 11:00:03 PM
post Re: Unknown Diode Replacement
[Beginners]
davekni
March 07, 2024, 10:55:40 PM
post Re: CM400 Induction Heater
[Electronic Circuits]
davekni
March 07, 2024, 10:46:42 PM
post Re: Frequency
[Transformer (Ferrite Core)]
davekni
March 07, 2024, 10:23:27 PM
post Unknown Diode Replacement
[Beginners]
Luca
March 07, 2024, 09:55:48 PM
post Re: GDT Driver
[Electronic Circuits]
Mads Barnkob
March 07, 2024, 09:55:04 PM
post Re: CM400 Induction Heater
[Electronic Circuits]
markus
March 07, 2024, 05:07:37 PM
post GDT Driver
[Electronic Circuits]
reklm
March 07, 2024, 04:17:12 PM
post Re: Frequency
[Transformer (Ferrite Core)]
Alberto
March 07, 2024, 01:03:47 PM
post Re: CM400 Induction Heater
[Electronic Circuits]
davekni
March 07, 2024, 05:12:31 AM
post Re: Secondary Splicing
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 07, 2024, 04:45:02 AM
post Re: CM400 Induction Heater
[Electronic Circuits]
petespaco
March 07, 2024, 04:32:17 AM
post Re: Secondary Splicing
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 07, 2024, 03:43:25 AM
post Re: DIY induction guns? (warning:long)
[Induction Launchers, Coil Guns and Rails guns]
Michelle_
March 07, 2024, 03:22:34 AM
post Secondary Splicing
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 07, 2024, 02:35:54 AM

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