Author Topic: HF Litz wire as a primary coil  (Read 2274 times)

Offline TMaxElectronics

  • High Voltage Engineer
  • ****
  • Posts: 297
  • Karma: +23/-0
    • View Profile
    • My random (and very empty) electronics blog
HF Litz wire as a primary coil
« on: November 27, 2020, 12:33:29 AM »
I was recently thinking what to do with my little bridge I made for my "small" coil, that kept blowing up drivers/IGBTs (https://highvoltageforum.net/index.php?topic=1058.0).
And since the IGBTs are very fast, I think I'll try my luck with qcw.

Now the question however:
I would like to use some HF Litz wire I got from an old induction cooker plate as the primary, because I have it around and it might fit quite well given the relatively high frequency required for a qcw coil.
But I can't really think of a way of tuning it properly after the coil is assembled, has anybody tried this before and got some tips for me?

Offline davekni

  • Executive Board Member
  • *******
  • Posts: 2744
  • Karma: +129/-1
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: HF Litz wire as a primary coil
« Reply #1 on: November 27, 2020, 02:18:49 AM »
One option is to tune by adjusting MMC capacitance.  That's what I use.  Also, the higher coupling coefficient you can get, the less critical tuning is.
David Knierim

Offline Da_Stier

  • High Voltage Technician
  • ***
  • Posts: 185
  • Karma: +13/-0
    • View Profile
Re: HF Litz wire as a primary coil
« Reply #2 on: November 28, 2020, 06:32:22 PM »
Is each strand on this kind of litz wire coated in some isolator or is it more like a normal wire with blank copper strands?
Maybe a brass clamp with some penetrating pins might be usable to move the feedpoint for tuning?

Offline Steve Ward

  • High Voltage Enthusiast
  • *
  • Posts: 48
  • Karma: +14/-1
    • View Profile
Re: HF Litz wire as a primary coil
« Reply #3 on: December 01, 2020, 01:47:10 AM »
Litz wire is often made from "solderable" magnet wire, which with a little abrasion while applying the iron will often succeed at wetting into the whole bundle of wires producing tap points which should only have a minor effect on the litz performance.

However, I'd agree with others that tuning the primary cap is a very practical way to avoid primary taps if you're careful about knowing your secondary parameters.  JavaTC is my go-to tool for designs. 

Ive built several QCWs with litz wire, and i will say it can make a significant difference in wire temperature (provided the litz is really spec'd for the high freq, your cooktop stuff might only be sized for 20-50khz, so its not as effective as the super fine stuff i used rated for 300-500khz), but generally the primary coil loss is relatively small compared to total energy, so you probably wont see any real boost in spark performance. 


Offline johnf

  • High Voltage Technician
  • ***
  • Posts: 192
  • Karma: +6/-0
    • View Profile
Re: HF Litz wire as a primary coil
« Reply #4 on: December 01, 2020, 07:03:56 AM »
As Da and Steve have said each strand is insulated.
Be warned some of these use polyimide coatings which are not solderable (easily).
Using Litz would tend to increase your "Q" by quite a lot (skin effect) which may also work against what you are trying to achieve. Circuit "Q" is almost always affected most by the quality of the inductor not the capacitor so high "Q" circuits tend to maximise C instead of L
High "Q" circuits tend to test drive circuit stability which in turn tends to make sacrifices to the gods of high dV/dt and dI/dt failures.

Offline TMaxElectronics

  • High Voltage Engineer
  • ****
  • Posts: 297
  • Karma: +23/-0
    • View Profile
    • My random (and very empty) electronics blog
Re: HF Litz wire as a primary coil
« Reply #5 on: December 01, 2020, 11:50:19 AM »
Quote
One option is to tune by adjusting MMC capacitance
Do you mean by adding or removing strings in a bank? I'm kind of hoping to find another big single cap that does everything I need it to do ;)

Quote
Be warned some of these use polyimide coatings which are not solderable (easily)
Yeah I have been using W210 copper wire for all of my tesla coils and it is a bit of a pain to connect.
And from lacquer color and the fact that it will potentially have a very hot frying pan on top of it I think that the wire I have is the high temperature stuff too.

Quote
...if you're careful about knowing your secondary parameters
For my experience (which I admit is not a lot :P) JavaTC can be quite a bit off if the turns count isn't spot on. But since I have everything I need to make one I think I'll just make the secondary, measure it's parameters and then design the primary accordingly.

One thing that I thought about was to use some sort of variable inductor. Basically another small coil made from wire that can easily be connected to for tuning that would drop the frequency just the last little bit. But I'm not quite sure how much useful adjustment rang I could get out of one.


Quote
High "Q" circuits tend to test drive circuit stability
How exactly is that? Just because the current rises much more sharply that in a low Q string or is there another mechanism that I don't know about?

Offline davekni

  • Executive Board Member
  • *******
  • Posts: 2744
  • Karma: +129/-1
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: HF Litz wire as a primary coil
« Reply #6 on: December 01, 2020, 07:38:53 PM »
"Do you mean by adding or removing strings in a bank? I'm kind of hoping to find another big single cap that does everything I need it to do "

Yes.  MMC arrays generally perform better (lower loss, higher current and voltage capability) than single large capacitors.  Even if you use one large capacitor, adding a few small ones in parallel would work for adjustment.

Adding an inductor in series or parallel will reduce effective coupling factor, the same as excess primary lead length does.  Unless you want less coupling, I wouldn't pursue that option.

My experience with resonant circuits such as DRSSTC is that high-Q improves stability.  I don't understand John's concern.  All my coils use litz-wire primaries.
David Knierim

Offline johnf

  • High Voltage Technician
  • ***
  • Posts: 192
  • Karma: +6/-0
    • View Profile
Re: HF Litz wire as a primary coil
« Reply #7 on: December 02, 2020, 07:43:14 AM »
David
 my concerns were when you operate outside of resonance. resonance is the holy grail and gives max power transfer
lower freq gives a capacitive type complex load and above resonance and inductive complex load.
add feedback without controlling phase and usually the circuit becomes unstable as phase goes towards 180 with circuit gain. Lots of solid state circuits do not have enough phase margin and with the lower freq end being capacitive coupled with more device gain due to the lower freq then the little gremins come out to play
Out of control loops like this are a silicon suppliers dream as you order more sacrifices from them as future offerings.
You and I know how to first simulate and blow up virtual devices before tempting the gods with real silicon and for my part every so often a silicon part tends toward permanent conduction and or oblivion for some unknown reason

all for now

Offline davekni

  • Executive Board Member
  • *******
  • Posts: 2744
  • Karma: +129/-1
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: HF Litz wire as a primary coil
« Reply #8 on: December 02, 2020, 07:14:18 PM »
John,

Certainly high-Q resonances are a problem when making broad-band (ie. DC up) feedback loops around them, such as voltage regulation in an SMPS.  Or, specific to my work experience, closed-loop position control around a motor/belt drive.  The belt (spring) and motor and load masses made a relatively-high-Q resonance.  That made high-bandwidth position control very difficult without instability.

On the other hand, for a resonant circuit being driven at resonance, high-Q usually helps keep the circuit locked to the desired frequency.  UD2.7 or similar controller will lock reliably to the highest-Q resonance.
David Knierim

High Voltage Forum

Re: HF Litz wire as a primary coil
« Reply #8 on: December 02, 2020, 07:14:18 PM »

 


* Recent Topics and Posts

post Re: Big Coil Build Log
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
Today at 05:47:34 AM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
davekni
Today at 04:45:07 AM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
MRMILSTAR
Today at 04:18:27 AM
post Push Pull VTTC
[Vacuum Tube Tesla Coils (VTTC)]
janno288
Today at 01:10:08 AM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 27, 2024, 10:54:52 PM
post Re: CM400 Induction Heater
[Electronic Circuits]
markus
March 27, 2024, 11:53:42 AM
post Re: OCD Triggering Early + Low Output
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 27, 2024, 05:14:36 AM
post Re: Is the UD2.7C under voltage lock out basically worthless?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 27, 2024, 04:47:48 AM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 27, 2024, 04:41:59 AM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
March 27, 2024, 12:04:34 AM
post Re: Super flat QCW simulation (does this look reasonable?)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
toooldforthis
March 26, 2024, 11:08:14 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 26, 2024, 11:07:20 PM
post Re: Is the UD2.7C under voltage lock out basically worthless?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 26, 2024, 10:46:29 PM
post OCD Triggering Early + Low Output
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Saattvik24
March 26, 2024, 09:03:43 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
March 26, 2024, 08:46:59 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 26, 2024, 05:02:18 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
March 26, 2024, 03:16:03 PM
post Re: CM400 Induction Heater
[Electronic Circuits]
Anders Mikkelsen
March 26, 2024, 01:41:49 PM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 26, 2024, 04:48:22 AM
post Re: Re-chargeable 1.5 volt lithium ion AAA batteries
[General Chat]
MRMILSTAR
March 26, 2024, 04:16:37 AM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 26, 2024, 04:16:24 AM
post Re: Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!
[Electronic Circuits]
davekni
March 26, 2024, 04:13:02 AM
post Re: CM400 Induction Heater
[Electronic Circuits]
davekni
March 26, 2024, 04:00:43 AM
post Re: Re-chargeable 1.5 volt lithium ion AAA batteries
[General Chat]
davekni
March 26, 2024, 03:19:18 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
thedoc298
March 26, 2024, 01:50:42 AM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 25, 2024, 08:05:02 PM
post Re: Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!
[Electronic Circuits]
Mads Barnkob
March 25, 2024, 07:41:29 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
March 25, 2024, 06:45:46 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 25, 2024, 05:44:25 PM
post Re: CM400 Induction Heater
[Electronic Circuits]
Anders Mikkelsen
March 25, 2024, 04:47:17 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
March 25, 2024, 04:27:22 PM
post Re-chargeable 1.5 volt lithium ion AAA batteries
[General Chat]
MRMILSTAR
March 25, 2024, 03:57:34 PM
post Re: CM400 Induction Heater
[Electronic Circuits]
markus
March 25, 2024, 02:06:41 PM
post Re: Odd MOSFET Driver Behavior
[Solid State Tesla Coils (SSTC)]
KrisPringle
March 25, 2024, 04:43:25 AM
post Re: Odd MOSFET Driver Behavior
[Solid State Tesla Coils (SSTC)]
davekni
March 25, 2024, 02:39:40 AM
post Re: Odd MOSFET Driver Behavior
[Solid State Tesla Coils (SSTC)]
KrisPringle
March 25, 2024, 12:47:09 AM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 24, 2024, 07:36:32 PM
post Re: My completed 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
Alberto
March 24, 2024, 07:27:24 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
MRMILSTAR
March 24, 2024, 04:25:23 AM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 23, 2024, 10:47:35 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
MRMILSTAR
March 23, 2024, 09:30:21 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 23, 2024, 04:34:31 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
MRMILSTAR
March 23, 2024, 03:04:25 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 23, 2024, 01:38:34 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
MRMILSTAR
March 23, 2024, 04:20:03 AM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
davekni
March 23, 2024, 12:54:30 AM
post Re: Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!
[Electronic Circuits]
davekni
March 23, 2024, 12:05:57 AM
post capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 22, 2024, 11:45:03 PM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
OmGigaTron
March 22, 2024, 11:30:09 PM
post Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!
[Electronic Circuits]
Mads Barnkob
March 22, 2024, 10:20:35 PM
post Re: Where's all this voltage coming from?
[Spark Gap Tesla Coils (SGTC)]
Benbmw
March 22, 2024, 09:21:13 PM
post Re: What actually kills MOSFETs?
[Beginners]
AstRii
March 22, 2024, 03:37:11 PM
post What actually kills MOSFETs?
[Beginners]
FPS
March 22, 2024, 05:09:20 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 22, 2024, 03:57:54 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 22, 2024, 02:59:25 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 21, 2024, 06:31:42 PM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
rikkitikkitavi
March 21, 2024, 03:08:01 PM
post Re: [WTS] IGBT, Ferrite, Capacitors, Tools, PSU, Industrial components and parts
[Sell / Buy / Trade]
Mads Barnkob
March 21, 2024, 01:37:32 PM
post Re: Difference between these transformers
[Transformer (Ferrite Core)]
Alberto
March 21, 2024, 11:42:07 AM
post Re: Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 21, 2024, 04:09:14 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 21, 2024, 02:15:31 AM
post My Homemade Structural Analysis X-Ray Machine
[X-ray]
Luca c.
March 21, 2024, 01:35:40 AM
post Re: Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Saattvik24
March 20, 2024, 10:40:00 PM
post Re: Difference between these transformers
[Transformer (Ferrite Core)]
Mads Barnkob
March 20, 2024, 08:03:41 PM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Mads Barnkob
March 20, 2024, 07:51:57 PM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
March 20, 2024, 10:39:47 AM
post Re: Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 20, 2024, 04:09:59 AM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 20, 2024, 01:13:23 AM
post Re: Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Keybored
March 20, 2024, 12:45:16 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 20, 2024, 12:30:30 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 19, 2024, 11:12:24 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Late
March 19, 2024, 09:47:49 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Late
March 19, 2024, 09:44:19 PM
post Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Saattvik24
March 19, 2024, 06:52:09 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 19, 2024, 05:02:44 PM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
Mads Barnkob
March 19, 2024, 05:01:41 PM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
March 19, 2024, 04:31:02 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
March 19, 2024, 03:59:54 PM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 19, 2024, 06:41:39 AM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
davekni
March 19, 2024, 04:05:49 AM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
OmGigaTron
March 18, 2024, 09:08:35 PM
post Re: Can I Trust This Super Cheap Site?
[General Chat]
2020-Man
March 18, 2024, 09:07:35 PM
post Re: Can I Trust This Super Cheap Site?
[General Chat]
Twospoons
March 18, 2024, 08:57:06 PM
post Re: Can I Trust This Super Cheap Site?
[General Chat]
MRMILSTAR
March 18, 2024, 03:51:33 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Late
March 18, 2024, 02:59:46 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Late
March 18, 2024, 02:33:25 PM
post Can I Trust This Super Cheap Site?
[General Chat]
2020-Man
March 18, 2024, 11:02:12 AM
post Re: Where's all this voltage coming from?
[Spark Gap Tesla Coils (SGTC)]
Twospoons
March 18, 2024, 02:36:11 AM
post Re: Best forum for vacuum tube amplifiers?
[General Chat]
Mads Barnkob
March 17, 2024, 07:42:55 PM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Michelle_
March 17, 2024, 04:15:14 PM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Michelle_
March 17, 2024, 05:05:04 AM
post Re: Where's all this voltage coming from?
[Spark Gap Tesla Coils (SGTC)]
davekni
March 17, 2024, 04:50:51 AM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Twospoons
March 17, 2024, 04:45:17 AM
post 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Michelle_
March 17, 2024, 04:17:51 AM
post Where's all this voltage coming from?
[Spark Gap Tesla Coils (SGTC)]
Terry
March 17, 2024, 01:29:32 AM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 17, 2024, 12:33:06 AM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Keybored
March 16, 2024, 08:46:20 PM
post Re: Bleeder resistor for MMC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hydron
March 16, 2024, 08:39:24 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hydron
March 16, 2024, 08:21:44 PM
post Best forum for vacuum tube amplifiers?
[General Chat]
yourboi
March 16, 2024, 08:20:13 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