PopularFX
Home Help Search Login Register
Welcome,Guest. Please login or register.
2021-12-01, 02:47:59
News: Check out the Benches; a place for people to moderate their own thread and document their builds and data.
If you would like your own Bench, please PM an Admin.
Most Benches are visible only to members.

Pages: 1 ... 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 31 32 33 34 ... 103
Author Topic: Dally, Shark & Ruslan workbench  (Read 72373 times)

Sr. Member
****

Posts: 343
    itsu:
    Meander means to wander, or walk through. Should not also mean by using a square wave, unless, he means to meander "search/scan" using a square wave.
    Wow, this is all getting very complicated... Good thing that Vasik is here to help.
    I wonder how Tariel Kapanadze ever figured out how to do all this. Or even Adrian.
    Somehow I think that the actual best results will not be where the math indicates, but possibly close to it. We'll see...

    NickZ
   

Sr. Member
****

Posts: 343
   So, even though the word means square wave in Russian, and does NOT mean meander (English) at all, we need to search/scan using a sine wave, instead?
   

Group: Professor
Hero Member
*****

Posts: 2595
"меандр" (meander) in Russian means square wave (50% duty cycle)
As an English noun it means "a series of regular sinuous curves..." followed by a watercourse.
It can also be a verb that means "to wander along curvy paths".

So upon encountering this word, I would've set my FG to output a sine wave if you hadn't explained it differently.
   

Hero Member
*****

Posts: 747
   So, even though the word means square wave in Russian, and does NOT mean meander (English) at all, we need to search/scan using a sine wave, instead?

I corrected my post on previous page.
First we search for two resonance regions with sine wave.
Then we switch to square wave and search for sub-harmonics.


---------------------------
The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
   

Group: Elite Experimentalist
Hero Member
*****

Posts: 3270

Following PP.pdf and video.

Grenade shorted, a current transformer inserted.
Using the inductor to feed in the FG signal (sine wave) looking for resonance peaks.
Found first peak around 1.341MHz (range 1.2 - 1.65MHz)
Found second peak around 5.771MHz (range 4.97 - 6.57MHz).

Switch over to square wave at 1st range frequency (1.2Mhz) / 10 so 120KHz and scan for harmonics in FFT mode on 1st peak....
Found 122KHz, 151 and 195 as match.

Scan for harmonics on 2th peak....
Found 122, 149, 175, 186, 199 etc. as match.

Best match for both peaks seems 122KHz, so will use its 5th subharmonic (24.4KHz) to tune the Push Pull frequency to.

Video here:  https://youtu.be/PqLWCmdn-w4

Itsu
   

Hero Member
*****

Posts: 747
Best match for both peaks seems 122KHz, so will use its 5th subharmonic (24.4KHz) to tune the Push Pull frequency to.

Video here:  https://youtu.be/PqLWCmdn-w4

Itsu,

cool! O0

Now you can make LC resonance at 122KHz and gradient coil at 24.4KHz
In youtube comments, Sergey writes that he has 0,03uF for inductor circuit, and 0,35uF on gradient coil.
This I think will be pretty close to your setup too.

Vasik


---------------------------
The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
   

Group: Elite Experimentalist
Hero Member
*****

Posts: 3270

Hmmm,   with "LC resonance at 122KHz", you mean the series LC resonance with the inductor? (so not 24.4KHz?)

If so;

Inductor measures 66uH, so (series) resonance (122KHz) will occure with a 0.02578uF (25.78nF) series capacitor.

Grenade ,measures 143uH, so (parallel) resonance (24.4KHz) will occure with a 0.2975uF (297.5nF) parallel capacitor.

Itsu

   

Hero Member
*****

Posts: 747
Itsu,

Hmmm,   with "LC resonance at 122KHz", you mean the series LC resonance with the inductor? (so not 24.4KHz?)
Yes, that how I understood Sergey's video.

Alexeev's variant (as I understand) would be 24.4Khz in inductor and 12.2Khz in gradient coil.
You probably can try it, if Sergey's variant does not perform well.

Quote
Inductor measures 66uH, so (series) resonance (122KHz) will occure with a 0.02578uF (25.78nF) series capacitor.
Grenade ,measures 143uH, so (parallel) resonance (24.4KHz) will occure with a 0.2975uF (297.5nF) parallel capacitor.

3-5 turns on ferrite core will add something to 66uH, so capacitance will be slightly  lower.

Vasik


---------------------------
The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
   

Group: Elite Experimentalist
Hero Member
*****

Posts: 3270

Thanks Vasik,  will keep it in mind.



I today installed the new kacher secondary (none spaced, non reversed at the top), 38.7m long wire, 0.71mm diameter, 233 turns on 53mm diameter cardboard former.
 
It turns out to be resonating around 1.238Mhz, which is not that far below the 1.4Mhz of the earlier secondary (spaced 1:1, reversed end).

Video here:  https://youtu.be/sODxGlggHm0

Itsu
   

Hero Member
*****

Posts: 747

It turns out to be resonating around 1.238Mhz, which is not that far below the 1.4Mhz of the earlier secondary (spaced 1:1, reversed end).


You just need adjust a little bit inductor place or maybe unwind few turns. But that can be done later during tuning.

BTW you get very nice scope traces. There are 3 different oscillations visible.

Vasik


---------------------------
The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
   

Group: Elite Experimentalist
Hero Member
*****

Posts: 3270
Hi Vasik,

with "inductor place or maybe unwind few turns" you mean the Inductor coil around the Grenade? (Why would that lower the Kacher resonance frequency?)

I was more wondering why there is so little difference between the resonance frequencies of the both Kacher secondaries.
First one (1.4Mhz) has way less turns / length and is spaced 1:1 compared to the new one (1.2Mhz).

Looks like there is another kacher resonance frequency determination factor in play here (cardboard former instead of pvc? 53mm diameter former instead of 50mm on the old one, ......?).



Anyway, yes i see those differences in the Kacher ringing signal, it depends on where i put the pickup probe, but basically i have not seen that on earlier kacher signals.

1 (red) would be the "normal" dampend ringing signal i guess,
2 (yellow) looks like a (2) superimposed sinewave(s), see (green trace) below,
3 (blue) could be an artifact of the scope


Interesting,   Itsu
   

Hero Member
*****

Posts: 747
Hi Itsu,

I was more wondering why there is so little difference between the resonance frequencies of the both Kacher secondaries.
First one (1.4Mhz) has way less turns / length and is spaced 1:1 compared to the new one (1.2Mhz).
Looks like there is another kacher resonance frequency determination factor in play here (cardboard former instead of pvc? 53mm diameter former instead of 50mm on the old one, ......?).
There are many factors here. I think it is good that you use cardboard.
There might be something in plastic tubes (e.g. graphite) that introduce loses.
Also spacing, how you implemented it ? with fishing line ? it also affects turn to turn inductance etc etc

Quote
Anyway, yes i see those differences in the Kacher ringing signal, it depends on where i put the pickup probe, but basically i have not seen that on earlier kacher signals.
1 (red) would be the "normal" dampend ringing signal i guess,
2 (yellow) looks like a (2) superimposed sinewave(s), see (green trace) below,
3 (blue) could be an artifact of the scope

I would guess 1 and 2 happen because inductor not matched to HV coil, so some beatings occur between them.
What inductor diameter you have ? it is recommended to be 1.62 x HV coil diameter.
What inductance and length ?
You can try add a variable capacitor in parallel to inductor and see what happen when you adjust it.

3 might be scope artifact, or... signs of that "mysterious" current from the ground wire we want to explore.
I not sure what power supply voltage you have, 24v probably to low for it to appear (not sure).

Vasik


---------------------------
The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
   

Group: Elite Experimentalist
Hero Member
*****

Posts: 3270

Quote
Also spacing, how you implemented it ? with fishing line ?


I double wound (bifilar) that first secondary, then removed one wire, leaving a spaced secondary.
I did cover it with insulation tape (the new one not), perhaps that influenced the inductance.


 
Quote
What inductor diameter you have ? it is recommended to be 1.62 x HV coil diameter.


Not sure what you mean with "inductor" and "HV coil".

The "inductor" (coil around the lower part of the grenade) is wound on a cardboard former (wrapped around that lower part Grenade) and is 8cm diameter.
The "HV coil" (antenna around the Inductor) has a diameter of 14.5cm (so 1.8 times BIGGER).


Quote
What inductance and length ?


For the inductor or HV coil?,   Inductor is 66uH, length 9.37m         HV coil (antenna) is 4.3uH, length roughly 2.3m


Quote
3 might be scope artifact, or... signs of that "mysterious" current from the ground wire we want to explore.
I not sure what power supply voltage you have, 24v probably to low for it to appear (not sure).


I have 24V input from a PS into the PCB and 12V (for now) from a battery on the Kacher primary coil.

Itsu
   

Hero Member
*****

Posts: 747
Itsu,

Sorry for confusion.
By some reason people tend to call "inductor" primary coils.
Personally I don't like it, but following this custom just to be better understood.

I made a picture :)
I mean what parameters (diameter, inductance, length) your kacher's (or Tesla's) primary coil (kacher's inductor) have ?
It is recommended to have it 1.62 x diameter of kacher's secondary (HV coil)
In your case 1.62 x 53 = 86mm would be optimal

Vasik


---------------------------
The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
   

Group: Elite Experimentalist
Hero Member
*****

Posts: 3270

Ok,   no problem  O0 , the kacher primary measures 2.2uH @ 100Khz and is on a 11cm diameter cardboard former (3 turns) and calculates to about 1.1m length.

So i will adjust that to a 86mm diameter former,   thanks.

Itsu
   

Hero Member
*****

Posts: 747
Ok,   no problem  O0 , the kacher primary measures 2.2uH @ 100Khz and is on a 11cm diameter cardboard former (3 turns) and calculates to about 1.1m length.

So i will adjust that to a 86mm diameter former,   thanks.

Sergey's recommendations about kacher's primary:
 inductance = N x inductance of 1 turn of HV coil (N=1,2,3...)
 length = 1/N of HV coil (N=1,2,3...)

Also instead of attaching extra capacitor, it is possible do adjustment by changing gaps between turns.
(may be make a wider coil former ?)

Vasik



---------------------------
The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
   

Group: Professor
Hero Member
*****

Posts: 2595
I did cover it with insulation tape (the new one not), perhaps that influenced the inductance.
Nah, tape will only influence the interturn capacitance by altering the dielectric constant.
Small changes in interturn spacing, even more so.
   

Hero Member
*****

Posts: 747
Nah, tape will only influence the interturn capacitance by altering the dielectric constant.
Small changes in interturn spacing, even more so.

And potentially can introduce loses, we don't know how good insulation tape behaves on HF.


---------------------------
The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
   

Group: Professor
Hero Member
*****

Posts: 2595
And potentially can introduce loses, we don't know how good insulation tape behaves on HF.
Yes. I am sure it has higher losses than air.
Take a look at the "Loss tangent" in this table for comparative values.
   

Group: Elite Experimentalist
Hero Member
*****

Posts: 3270
New primary (5 turns at 8.6cm diameter) measures 2.9uH.
New Kacher secondary measured 274uH and with 233 turns that makes 2.9uH/turn.

Length primary calculates ~1.35m,   
Length kacher secondary is ~18.7m,

Not sure how all this relates to the above recommendations, but the resulting Kacher signals do not deviate much compared to earlier primary signals.


Itsu
   

Hero Member
*****

Posts: 747
New Kacher secondary measured 274uH and with 233 turns that makes 2.9uH/turn.

Itsu,

Do you mean 274 / 233 / 233 = 5nH ?

Vasik

PS yes, verpies, you right L ~ N^2
« Last Edit: 2021-05-15, 19:20:08 by Vasik041 »


---------------------------
The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
   

Group: Professor
Hero Member
*****

Posts: 2595
New Kacher secondary measured 274uH and with 233 turns that makes...
5nH/turn2
   

Group: Elite Experimentalist
Hero Member
*****

Posts: 3270
Itsu,

Do you mean 274 / 233 / 233 = 5nH ?

Vasik

PS yes, verpies, you right L ~ N^2

Hmmm,  well i meant 274/233 = 1.17uH/turn (not sure where the 2.9 came from).

No idea why you divide by another 233 or what this "inductance = N x inductance of 1 turn of HV coil (N=1,2,3...)" means.


Itsu
 

   

Hero Member
*****

Posts: 747
"inductance = N x inductance of 1 turn of HV coil (N=1,2,3...)" means

This means that it is good to have inductor inductance multiple of one turn of HV coil's inductance

like 2.9uH ÷ 0.005 = 580

this already too difficult to measure and adjust, probably can leave it as it is.

Vasik
« Last Edit: 2021-05-15, 20:36:15 by Vasik041 »


---------------------------
The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
   

Group: Elite Experimentalist
Hero Member
*****

Posts: 3270
You lost me there for the moment, but never mind, i can always change both the kacher secondary and/or primary.


Found a good yoke to be used in the push pull circuit:



Gaps have insulating tape inbetween, so will start with both primaries (10 turn each) on one half, and the 3 turn secondary on the opposite half.
Over the both primaries i will lay then the 25 turn tertiary coil.

Itsu
   
Pages: 1 ... 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 31 32 33 34 ... 103
« previous next »


 

Home Help Search Login Register
Theme © PopularFX | Based on PFX Ideas! | Scripts from iScript4u 2021-12-01, 02:47:59