Dally, Shark & Ruslan workbench

[Vasik041]

I completed the PushPull Kacher synced pcb and made some first tests:

Scope shows yellow/blue the TL494 output (20KHz @ 33% Duty Cycle), purple inverted output to kacher driver.

Frequency adjustable between 17.9KHz and 117KHz.

Also winding the "inductor" around the lower part Grenade using the below (¼ wave length) table, meaning around 9.5m long, aiming for half the Grenade inductance (143uH), so 72uH.

Itsu

Nice progress Itsu 
According to my understanding you will need tune push pull to selected resonance frequency and then grenade coil to be approx. 30 degrees ahead.
Here a picture

Text on top: scope traces for 38/19m coils. Yoke primary coils are 14 turns, 5 turns for resonance on 19m and 0.15uF, 0.3uF on gradient coil. Load connected through diode bridge and non-polar filter capacitors 20uF.

Yellow trace: gradient coil current 23 degrees ahead of LC
Red: push pull LC current (through capacitor)

Vasik

[Vasik041]

Itsu this circuit might be of use, no idea where it came from note large caps used around trhe coils no comments on them though.
SIL

I think this is from one of earlier Alexeev's schematics, here is original (I guess)

Edit: here can be found related archive https://disk.yandex.com/d/OSbLob07syV5t

[AlienGrey]

I think this is from one of earlier Alexeev's schematics, here is original (I guess)

On an educational aspect here, thanks for that diagnosium  Re demo link p13 one of vids shows 90
phase shift added to wave before it goes into yoke.

Top left of pic  >    https://www.youtube.com/watch?v=Ev-44qaQ9dk

Wesley's news video shows tap at 3/4 way along tesla coil (or is it FW grenade,
is that introduced into system some where ?    >    https://www.youtube.com/watch?v=IAPe3DiYt2o

SIL

[Vasik041]

On an educational aspect here, thanks for that diagnosium  Re demo link p13 one of vids shows 90
phase shift added to wave before it goes into yoke.

Wesley's news video shows tap at 3/4 way along tesla coil (or is it FW grenade,
is that introduced into system some where ?

SIL

AlienGrey,

could you please give links to the videos you mention ?

Thanks,
Vasik

[AlienGrey]

Will try and find Wesleys stuff might take some wime.

modified last post with link

[Vasik041]

Top left of pic  >    https://www.youtube.com/watch?v=Ev-44qaQ9dk

AlienGrey,

Here some information about the clip (see attached file).
On the left top presented a example used to illustrate how energy extracted using phase shift.
It said that in nature all oscillations have 90 degrees phase shift.
So if we want extract something we need create phase shift.

Vasik

[Verpies]

Here some information about the clip (see attached file).

In that file, you use the word "modulation" several times.
What type of modulations is it?  There are 4 basic types (FM, AM, PM, PW) and many subtypes.

[Vasik041]

In that file, you use the word "modulation" several times.
What type of modulations is it?  There are 4 basic types (FM, AM, PM, PW) and many subtypes.

It is AM.

[Vasik041]

Wesley's news video shows tap at 3/4 way along tesla coil (or is it FW grenade,
is that introduced into system some where ?    >    https://www.youtube.com/watch?v=IAPe3DiYt2o

AlienGrey,

You mean this picture ?
I guess that this is gradient coil with spark gap excitation.
We saw that RuslanK made all kind of variations of excitation (Tesla coil, spark plug, nanoseconds generator)
but always something like a gradient coil is present.
I am attaching schematic of HV module for reference.

Vasik

PS and a good picture of the coil

[AlienGrey]

Its that coil and som others in one of Wesley news vids with a close up of a needle stuck in the coil at the start of the last 90 deg section
you cant realy see it as the resolution in that video loses it, possably at 270 deg

SIL

[Vasik041]

Its that coil and som others in one of Wesley news vids with a close up of a needle stuck in the coil at the start of the last 90 deg section
you cant realy see it as the resolution in that video loses it, possably at 270 deg

SIL

I don't think that reverse engineering bring us somewhere... but anyway here some more pictures
and link to the fragment of original video https://www.youtube.com/watch?v=nGgz54VjLDk

Vasik

[Itsu]

I used ¼ of the 37.5m of the Grenade wire to make an inductor, so 9.37m.

After winding it around the lower part of the Grenade, it turns out to measure 63uH which is lower then my aim which was 72uH (½ of the 143uH of the Grenade).
But i don't think i can make it increase in inductance other then adding length/turns which i want to avoid.

Anyway, i hooked up the kacher/antenna and the PushPull Kacher driver circuit.

But i am not sure if what i see is correct, see screenshot which shows:
green the Kacher/antenna output (isolated probe)
yellow the kacher drive transistor base signal
purple the "TC" signal driving IR2113.








I would expect to see a much shorter base signal pulsing the kacher on/off like in this circuit:




I have 5V @ 300mA on the Collector / primary Kacher coil


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

Itsu 

[Verpies]

I would expect to see a much shorter base signal pulsing the kacher on/off like in this circuit:

What are the signals on pins 1 & 7 of the IR2113 ?
Is this IC the IR2113 or IR2113S ?

Also, how does that base signal look with the antenna wire disconnected from the base and the collector connected to +V with a non-inductive resistor^*?

^{*Large enough as not to exceed the transistor's maximum collector current (I_C).}

[Vasik041]

Hi Itsu,

It seems that there is an error in the original schematic, or I miss one inversion (sorry for that).
According to my understanding TC signal should be inverted.
You can achieve this by reconnecting it like shown on the picture (pls. see attached)
Or perhaps you can make it shorter adjusting RV7 ?

So most of the time kacher should be off and Q6 base grounded through Q4 (IRF3205)
and it should be on just for a short time (5-6 HF pulses)
Also I would suggest do not connect scope probe directly to hot end of the kacher secondary coil, it will offset frequency (just left scope probe laying close to it)

About gradient coil inductor: Sergey says that you can increase inductance if you add some cardboard (or thick paper) under it (so diameter will be bigger ans so inductance)

Vasik

Edit: removed picture because it not needed

[Vasik041]

Itsu,

After checking schematic one more time I found my mistake.
No need for extra inversion.
IR2110 outputs 1 and 7 are swapped.
You can fix it by re-soldering R11 and R12.

Vasik

[Itsu]

What are the signals on pins 1 & 7 of the IR2113 ?
Is this IC the IR2113 or IR2113S ?

Also, how does that base signal look with the antenna wire disconnected from the base and the collector connected to +V with a non-inductive resistor^*?

^{*Large enough as not to exceed the transistor's maximum collector current (I_C).}

The signals on pins 1 and 7 of the IR2113 are like shown in the above handdrawn diagram, the delay on pin 7 is very small, but they look like it should be.

Its an IR2113.


As i build this circuit before (2018) for Nick, i know how the base signal should look like, see this video from then:

https://www.youtube.com/watch?v=qHNv5wiKkTY   where at 2:20min i have this screenshot (Blue Kacher HV, probe laying agains coil, yellow base signal):








I am not quite convinced about Vasik his comments below about swapped connections, but will check into that.

Also, how does that base signal look with the antenna wire disconnected from the base and the collector connected to +V with a non-inductive resistor*?

_{*Large enough as not to exceed the transistor's maximum collector current (IC).}

I can try that tonight.


Itsu

[Itsu]

Hi Itsu,

It seems that there is an error in the original schematic, or I miss one inversion (sorry for that).
According to my understanding TC signal should be inverted.
You can achieve this by reconnecting it like shown on the picture (pls. see attached)
Or perhaps you can make it shorter adjusting RV7 ?

So most of the time kacher should be off and Q6 base grounded through Q4 (IRF3205)
and it should be on just for a short time (5-6 HF pulses)
Also I would suggest do not connect scope probe directly to hot end of the kacher secondary coil, it will offset frequency (just left scope probe laying close to it)

About gradient coil inductor: Sergey says that you can increase inductance if you add some cardboard (or thick paper) under it (so diameter will be bigger ans so inductance)

Vasik

Edit: removed picture because it not needed

Itsu,

After checking schematic one more time I found my mistake.
No need for extra inversion.
IR2110 outputs 1 and 7 are swapped.
You can fix it by re-soldering R11 and R12.

Vasik

Vasik,   

yes, i had the HV probe on the insulated part of the Kacher magnetwire, but yes, i should have put it near, not connected (insulated)

Concerning the low (62uH) inductance of the inductor, i saw that comment of stalker using cardboard to tune the inductance, but would have expected
that it would get (even) lower when adding cardboard inbetween, so will try lateron to add cardboard in trying to increase inductance.


Not sure about the swapped connections on IR2113, i measured pins 1 and 7 and they look ok to me (7 inverted and somewhat delayed compared to 1).

Also the connections on the PCB, the diagram from it and the handdrawn diagram from stalker looks to be the same (no swaps).


But i will take a closer look tonight


Itsu

[Vasik041]

Itsu,

I think that pins swapped in PCB, please check.

Regrading tuning of the antenna in your video, here is Alexeev's video transcript explaining how it should look like.
Sergey Stalker says that ferrite rod should be "low frequency" i.e. rods from radio (magnetic antenna) are not suitable here. It is ok to use ring or some other shape core, but it should have big loss after 1MHz.

Vasik

[Itsu]

Hi Vasik,

Well, like you can see on your own expanded / corrected view in post #364, the routing goes as follows (red traces):



Comparing to the diagram and handdrawn circuit, thats how it should be i think.


Ok about the s=tuning.pdf, i will have a look, thanks.


Itsu

[Verpies]

The signals on pins 1 and 7 of the IR2113 are like shown in the above handdrawn diagram, the delay on pin 7 is very small, but they look like it should be.

Yeah, but that diagram does not show me the DC voltage levels of these pulses in your circuit nor the real the phase offset between these pulses

[Verpies]

It seems that there is an error in the original schematic, or I miss one inversion (sorry for that).

I did not check the schematic, so don't take my silence as a sign that it is OK.

Actually, I do not understand why this circuit is configured that way at all, i.e.: a 230V, 15A BJT being driven by several MOSFETs.
Why not use one high-power N-ch MOSFET being driven by a specialized gate driver (e.g. the UCC27511), like it is done usually?

Also, I do not understand why the low/high side driver (IR2113) appears to drive two N-Channel MOSFETd (Q3 & Q4) which have their both sources grounded. 
Alas, the entire purpose of a high-side driver is to drive the gate of an N-channel MOSFET, which typically has its source connected to a high voltage rail ( i.e.: not grounded ! ) in order to completely avoid using a P-channel MOSFET (like the Q5^*).

The high half of the IR2113 driver simply:
1) connects the HO output to the VB input when the the HIN input is high (and SD input is low).
2) connects the HO output to the VS input when the the HIN input is low (or SD input is high).
...while the VS and VB inputs are at voltage levels which are typically well ABOVE ground (also VB > VS+8.6V )^**.

Below is a diagram of this typical connection from the IR2113's datasheet:



The only advantage of the IR2113 driver (which are two drivers in one package: a low-side driver and high-side driver) over the UCC27511 driver, is its duality and the ability to pull up and pull down the load solely with N-ch MOSFETs, while an N-ch MOSFET driven by the single UCC27511 driver can only pull down the load.
By connecting together the COM and VS pins of the IR2113, that "push-pull" advantage solely with N-ch MOSFETs, is nullified.

^{* this also makes the blocking diode on its drain unnecessary (re.: SR510).
** which is why I wanted to see these voltage levels simultaneously on both output pins.}

[Vasik041]

Hi Vasik,
Well, like you can see on your own expanded / corrected view in post #364, the routing goes as follows (red traces):
Comparing to the diagram and handdrawn circuit, thats how it should be i think.
Ok about the s=tuning.pdf, i will have a look, thanks.
Itsu

Itsu,

I checked one more time and I still think that pins 1 and 7 should be swapped on PCB.
Please re-check.

Vasik

[Vasik041]

I did not check the schematic, so don't take my silence as a sign that it is OK.

Actually, I do not understand why this circuit is configured that way at all, i.e.: a 230V, 15A BJT being driven by several MOSFETs.
Why not use one high-power N-ch MOSFET being driven by a specialized gate driver (e.g. the UCC27511), like it is done usually?

Also, I do not understand why the low/high side driver (IR2113) appears to drive two N-Channel MOSFETs (Q3 & Q4) which have their both sources grounded. 
Alas, the entire purpose of a high-side driver is to drive the gate of an N-channel MOSFET's, which typically has its source connected to a high voltage rail ( i.e.: not grounded ! ) in order to completely avoid using a P-channel MOSFET (like the Q5^*).

The high half of the IR2113 driver simply:
1) connects the HO output to the VB input when the the HIN input is high (and SD input is low).
2) connects the HO output to the VS input when the the HIN input is low (or SD input is low).
...while the VS and VB inputs are at voltage levels which are typically well ABOVE ground (also VB > VS+8.6V )^**.

Below is a diagram of this typical connection from the IR2113's datasheet:

The only advantage of the IR2113 driver (which are two drivers in one package: a low-side driver and high-side driver) over the UCC27511 driver, is its duality and the ability to output bipolar waveforms (colloquially: AC), while the UCC27511 driver can output only unipolar pulsating DC waveforms. 
By connecting together the COM and VS pins of the IR2113, that "AC output" advantage is nullified.

^{* this also makes the blocking diode on its drain unnecessary (re.: SR510).
** which is why I wanted to see these voltage levels simultaneously on both output pins.}

Yes, I agree, this schematic looks odd for professional eye,
but it will work ok, we don't need anything else at this point.

Vasik

[Itsu]

Yeah, but that diagram does not show me the DC voltage levels of these pulses in your circuit nor the real the phase offset between these pulses

Ok,  here the IR2113 pin 1(blue)  and pin 7 (yellow) signal / relations:






Itsu

[Itsu]

Itsu,

I checked one more time and I still think that pins 1 and 7 should be swapped on PCB.
Please re-check.

Vasik

I think you are right,     naming the Fets (Q4, Q3 etc.) on the drawing clears things up, Q4 should be driven by pin 7,   Q3 by pin 1, now its reversed,  i will change and recheck.

Itsu