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2018-11-15, 23:06:47
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Author Topic: Controller No5 With Protection - Looking for Explosions  (Read 85557 times)

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OK thanks

I don't remember using enamelled copper bifilar wire for the coils, for the moment forget the loop with the load resistor as we need to work out why all that noise is following the sharp pulse, try another bifilar coil that's straight but try using small guage PVC wire side by side to form a bifilar 20 to 40 turns each coil, then scope across the coils, if we get that noise then we know it must be the fet stages, if the noise disappears then we know it's the close coupled enamelled bifilar wire, I would guess it's the wire as we don't want strong coupling between each bifilar coil, infact it is possible to create the pulse with 2 monfilar coils 1 foot apart, I have a video showing this somewhere.

Ok, i made another bifilar coil that's straight but using small gauge wire side by side to form a bifilar
100 turns each coil (wire from an ethernet cable which was untwisted).

Same setup on Peters box as before, but signals look different.

Below first picture is a screenshot from the last video above showing the signals with the magnetwire coils.

The second screenshot is from todays test using the straight non magnetwire coils.
I have put up some lines showing what i think are the 2 pulses (250ns apart) while the other 2 pulses/signals are mere
reflections i think.

Video here:  https://www.youtube.com/watch?v=Iqv6VW2Exrg

Itsu
   

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If this is Meyer related at all, then this ringing would be detrimental to the purity of resonance inside the metal.
Also, in such case, external magnetic fields should influence the effect.

https://youtu.be/EDyxBWXp6IU

I had a double barmagnet (neo's) next to the bifilar magnetwire coil which has a slight attraction to the inner
copper cladded steel 1 turn coil inside the bifilar coils.

But thats the only magnetic field in the area around this setup.

I had that magnet there during all my earlier tests which did show / produced crackling and oscillations.
It now seem to have no effect at all, or very faint.


Itsu 
   

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Higher magnetic flux density (B) is not always better.
Uniformity is often more important than density, because the lack o uniformity causes decoherence.

Don't discount the Earth's magnetic field concentrated by steel furniture elements, pipes and rebar.
Also, power supply transformers can be  a source of alternating magnetic fields. They leak the most when they are overloaded.

IMO the pulse repetition frequency should be as low as possible if the purity of resonance in the metal is the goal.
Pulsewidths are OK.

If distortions of the pulses are caused by classical transmission line reflections, then the usual termination techniques are the remedy.
   

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I detect some strong 50Hz emf around my bench, so there could be a strong magnetic field too i guess.
Not sure where it comes from, probably from the amount of test equipment and power supplies.

I can test with a lower (1 Khz) prf, i know already the pulses look different (cleaner) then.

I mentioned "reflections" above, concerning the double pulse seen per MOSFET, but i think i really should
say induction, but finding out the characteristic impedance of my bifilar coil / transmission line could
prove usefull.

Thanks,  Itsu
 
   

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Buy me some coffee
Itsu the new wire is it multistranded or single core, use multistranded.

Verpies yes it is possible that the fets were avalanching due to the size and sharpness of the pulse i suppose, but remember when you have good pulses, things around the bench start mailfunctioning / crashing,i suspect the em pulses emitted were triggering the fets gate to cause noise bursts, the crackling is another thing of debate, i know you can get very thin magnet wire to produce large magnetic fields during crackling.

see video here
http://www.youtube.com/watch?v=O8GgiEeH1W4&feature=BFa&list=ULCjmKlUHU_OQ&index=1
   

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Peter,  its multistranded.

Nice video showing the effects, i had similar effects earlier, but not lately.

Itsu
   

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These are the signals coming out of Peters box around 220ns phase setting.
These are  being fet into the IXDD604PI dual driver.

I think they will strongly contribute to the double pulse seen by each MOSFET.

Need to find a way to filter out or suppress those ringing signals as they false trigger the MOSFETs.
They are not there or much less between 0 and 180ns phase.

Itsu
   

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tExB=qr
is that located near the steel core wire or any other ferromagnetic material?
   

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Buy me some coffee
These are the signals coming out of Peters box around 220ns phase setting.
These are  being fet into the IXDD604PI dual driver.

I think they will strongly contribute to the double pulse seen by each MOSFET.

Need to find a way to filter out or suppress those ringing signals as they false trigger the MOSFETs.
They are not there or much less between 0 and 180ns phase.

Itsu

Hi Itsu
That does not look too good, strange the noise is after the second pulse

Try scoping across the fets supply rails at the chip.
   

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Grumpy,

this is at the input to the MOSFET driver chip, without the steel core wire or any other ferromagnetic material or magnet near.



Peter,

Yes the noise/ringing looks delayed somehow, and its also visisble on the drains and across the bifi coil.

I will use a battery combo (24V) to power your box instead of the double PS.

Perhaps its like verpies mentioned some (delayed) reflections from the bifilar coil / transmission line.


Itsu   

   

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Buy me some coffee
It looks like some sort of ground noise to me, the 2 output wires from the generator (0V and Signal out) for each channel should be connected across the driver chip and be as short as possible, so you have 4 wires (2 from each channel) going to each IX driver, I separated the driver and fet into a module so each driver and fet were totally separate circuits and each driver used a 7818 regulator to supply 18V to the driver chip with caps ect.
   

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Ok, i am using the PCB you send me which had the 2 white noise generators (Pic's) on it (not in use now) and
which has only 1 dual MOSFET driver and the both MOSFETs close together with common ground.

So i need to build a new setup using your box and new apart paths with a single driver and MOSFET each.

Itsu
   

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Buy me some coffee
Oh I see, well I never did get round to testing that board but it does look to me that 1 chan of the fet driver is affecting the other, maybe someone with better knowledge might be able to work out why the noise.

   

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Peter,

no problem, the funny thing though is that i already have build this seperate driver / MOSFET setup, see here:
http://www.overunityresearch.com/index.php?topic=272.msg59280#msg59280

The outcome was a nice gate signal (see that post screenshot), but also that the crackling or any other effect
(oscillations?) had disappeared.

So i still have that build, so could use it, however will it be of any use in finding (back) the crackling?

I know,  just try it.


Itsu
   

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Buy me some coffee
Hi Itsu

I'm not really sure why they are not appearing, what happens if you go back to the irf40 does  the crackling reappear.
   

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Peter,

i very much appreciate your comments and suggestions, and understand that you are anxious to help, but i severall
times now get the feeling that you are not quite following what i am doing.

I  know that you are very busy and lack the time to work on your own projects let alone to help me, but it is
not very productive for me nor for you when we are not on the same wavelength.

I am already back to the IRF840 MOSFETs, see here:  http://www.overunityresearch.com/index.php?topic=272.msg70150#msg70150

But they do not return the crackling, but presently i am on the straight coreless bifilar multistranded wire coils which
up till now never showed any abnormal behaviour, so i do not expect any crackling now.


I have the IRF840's on another pcb which has seperate paths and seperate single drivers (IXDD614PI) and doing some tests
on this coreless coil to see how the pulses look now.
I still see the noise and dual pulses on the drains, so need to further investigate where they come from.

Itsu
   

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I am starting to loose MOSFETs now.

I have the seperate drivers (IXDD614PI's) to seperate MOSFETs going to the coreless bifilar coils.

At 41V on the drains i lost an IRF840 (5A on the PS and one of the 2 was hot).
After installing another IRF840, the other one went off the same way.
Installed IRFP460's, but again one went off quickly. (all drain / source around 1 to 100 Ohm).

Lowered the driver voltage from 20V to 15V, and set the current limiter to minimum.
Now the short still happens, but the MOSFETs stay alive, and i see that it happens above 35V on the drain and
at about 205ns pulse phase.

Peters box has a 15ns offset (shows 0ns phase, but in reality its 15ns), so the shorts occure around 220ns.

I was able to capture the spike across the coil when the short happens, see screenshot.

The yellow trace is as said from across one of the bifilar (coreless) coil.
The 2 pulses on the left half are the "normal" pulses from the both MOSFETs and increase in distance till here at
about 220ns apart. (still not know why i see the 2 pulses when scoping 1 coil/drain). 

The PS went into current limiting and the spike occures.
Guess when i have no current limitation, the spike will be much higher destroying the MOSFET.
Could it be avalanching?

Not sure why it happens about 450ns after the last pulse ended.

Itsu
   

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I am starting to loose MOSFETs now.
When you scope the drain voltage while varying the delay, do you see the reflection from the coil superimpose on the next pulse occurring 220ns later ?   ...or after a multiple of the reflection's round-trip time?
   

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No, not really, some 8Mhz ringing but no reflections, see screenshot 1 of the both drains at about 170ns delay.

The 2th screenshot show a capture with the same settings as above (also the drain signals) but with the glitches active. 

Video here (glitches visible almost at the end):  https://www.youtube.com/watch?v=NPk-g9kbEjg

I added another screenshot 3 with a wider view of the noise,   we see the drain pulses on the far left, then the massive noise.


Itsu
   

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I put in my 900V CREE MOSFETs again like i did before here: 
http://www.overunityresearch.com/index.php?topic=272.msg59108#msg59108

And again like before i am not able to summon these glitches.
I increased the driver voltage to 20V, but these CREE MOSFETs won't show any form of noise or glitches.

Back to the IRF460's again (driver to 15V) and again i have these glitches.

Guess that the CREE's 900V threshold or any other parameter somehow prevent these glitches from happening.

Itsu
   

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It is possible with a Test Setup and a Variable Voltage Supply to
evaluate the Breakdown/Avalanche Voltage of the MosFet which
is developing the strange "noise."  That might nail it down as far
as the source of the strange behavior.  I believe it was Verpies a
little ways back who suggested that may be the cause.

Either the Body Diode or the MosFet region could be responsible.
It would be very difficult perhaps to isolate the actual area.


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"Truth: the most deadly weapon ever discovered by humanity. Capable of destroying entire perceptual sets, cultures, and realities. Outlawed by all governments everywhere. Possession is normally punishable by death." - John Gilmore (1935- ) Author
   

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Video here (glitches visible almost at the end):  https://www.youtube.com/watch?v=NPk-g9kbEjg
Is the ringing after the pulse, changing its frequency or is it my imagination ?
Does waving ceramic magnets in the vicinity alter it ?

I put in my 900V CREE MOSFETs again like i did before here: 
http://www.overunityresearch.com/index.php?topic=272.msg59108#msg59108
And again like before i am not able to summon these glitches.
Either these stronger MOSFETs stop breaking down or their different junction capacitances affect the system differently.

P.S.
How is that coil connected to these MOSFETs ?
Are there any chokes in the supply rails ?  Where exactly?
« Last Edit: 2018-11-14, 22:39:36 by verpies »
   

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muDped,

yes these glitches are very hard to summon or to manipulate as they are able to damage stuff.




verpies,

Quote
Is the ringing after the pulse, changing its frequency or is it my imagination ?
Does waving ceramic magnets in the vicinity alter it ?


I will have to find out later tonight, i think the frequency stays the same.
Will wave a ceramic magnet also tonight.

The below picture shows how the MOSFETs are connected to the coil, no choke is used.

Peters box and the driver chips are fet by a stack of 2 series batteries at 25V, all grounds connected
together at a single point.

Itsu
   

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no choke is used.
Not even for supplying the MOSFET drivers ?
   

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The MOSFET drivers are powered from 2 batteries (24V), have their own LM350 regulator (15 - 20V) and are as normally
isolated/decoupled with a 1mH choke and tantalium (39uF) and ceramic (0.1uF) caps.

Itsu
   
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