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Author Topic: A closer look at a simulated Negative resistance coil.  (Read 58698 times)

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The graph of COP against frequency would reveal whether the math behind the negative resistance is correct since that definitely shows a peak at a certain frequency.
Any preference for load resistor value?
   

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OK i used 510R


215khz i=72.4 lcv=675 load=4.6 pin=48.87mw pout=41.49mw cop=0.849
245khz i=72.4 lcv=757 load=4.90 pin=54.80mw pout=47.08mw cop=0.859
297khz i=72.3 lcv=875 load=5.17 pin=63.26mw pout=52.41mw cop=0.828
378khz i=68.5 lcv=1.04 load=5.78 pin=71.24mw pout=65.51mw cop=0.920
510khz i=67.5 lcv=1.06v load=5.8 pin=71.55mw pout=65.96mw cop=0.922
744khz i=66.7 lcv=1.17 load=5.76 pin=78.04mw pout=65.05mw cop=0.834
892khz i=63.8 lcv=1.2 load=5.77 pin=76.56mw pout=65.28mw cop=0.853
1.14mhz i=63.3 lcv=1.28 load=5.6 pin=81.66mw pout=61.49mw cop=0.753
1.32mhz i=61.6 lcv=1.22 load=5.25 pin=75.15mw pout=54.04mw cop=0.719
1.56mhz i=62.5 lcv=1.26 load=5.16 pin=78.75mw pout=52.20mw cop=0.663
1.84mhz i=63.7 lcv=1.29 load=5 pin=82.17mw pout=49.02mw cop=0.597
2.15mhz i=57.6 lcv=1.16 load=4.40 pin=73.89mw pout=37.96mw cop=0.514
3.30mhz i=56.2 lcv=1.25 load=3.4 pin=70.25mw pout=22.66mw cop=0.323
4.81mhz i=42.4 lcv=1.45 load=2.49 pin=61.48mw pout=12.16mw cop=0.198
6.76mhz i=21.2 lcv=2.08 load=1.31 pin=44.09mw pout=33.65mw cop=0.763

Not sure what happened at 6.76MHz i will look at that sudden jump up a bit more

EDIT
The graph was not very good so have now replaced it with a better one.
« Last Edit: 2015-02-22, 08:00:18 by Peterae »
   
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Thanks for all those measurements.  The sudden jump at 6.76MHz is almost certainly due to a resonance outside our area of interest.  If you ignore that then we have graph rising to a peak value then falling off at the higher frequencies, which is exactly what I would expect.  It is that rise to a peak value that is of interest since that is indicative of some internal effect that eventually gets overridden by the HF core losses.  The two charts here show (a) the complex permeability values that were derived using math functions to fit the actual ones and (b) the negative resistance that appears using the formula in my original paper.  The actual values shown are of no interest since I can change a small parameter and get widely different ones.  What is of interest is the value increasing with increasing frequency (as per my formula) but then getting overridden by the increasing positive value from core losses.  I think your results show this tendency.

So I suggest you now concentrate at a fixed frequency where the COP is maximum between 378 KHz and 510 KHz.  Then create a plot of COP against different load resistor values.  You should find an optimum value where COP is greatest.  Since you are already at a COP greater than 0.9 this bodes well for getting near to unity even if not beyond that.  When you consider that (a) the core has losses and (b) the coils have losses then a COP near unity could well mean that there is an OU effect going on.  You might then try Litz wire to minimise coil losses.  Anyway it appears you now have something tangible to get your teeth into.  Well done!

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Thanks Smudge
Good plan, loads next then  O0

Still trying to track that peak in COP

did some more earlier so it looks like i need to go a little lower in frequency yet somewhere between 297 & 631khz to zoom in on that peak a bit.
631khz i=70.1 lcv=1.18 load=6.03 Pin=83.78 Pout=71.30 COP=0.851
661khz i=70.9 lcv=1.21 load=6.11 Pin=95.59 Pout=73.20 COP=0.766
702khz i=70.9 lcv=1.22 load=6.15 Pin=86.49 Pout=74.16 COP=0.857
   

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I just crunched some data from earlier in the day, this lot was done with a 100 Ohm load.

The COP is all over the place and i think it's because of the lower amplitude readings introducing more readable errors  O0

load 100ohm
403khz i=63.2 lcv=261mv load=1.14 Pin=16.49 Pout=12.99 COP=0.787
480khz i=63 lcv=267 load=1.14 Pin=16.82 Pout=11.14 COP=0.662
543khz i=63.3 lcv=269 load=1.14 Pin=16.90 Pout=12.99 COP=0.7686
625khz i=62.8 lcv=270 load=1.13 Pin=16.96 Pout=12.77 COP=0.753
694khz i=62.9 lcv=276mv load=1.08 Pin=17.36 Pout=11.66 COP=0.672
781khz i=61.4 lcv=271mv load=1.1 Pin=16.64 Pout=12.77 COP=0.767
961khz i=63.7 lcv=293 load=1.15 Pin=18.66 Pout=13.23 COP=0.709
1.39mhz i=61.2 lcv=293 load=1.09 Pin=17.93 Pout=11.88 COP=0.663
1.79mhz i=61 lcv=311 load=1.07 Pin=18.97 Pout=11.45 COP=0.604

PS i did try your subtraction idea but it did not work well on my scope, current is 10's of mv and LC voltage is volts, subtract the 2 and you loose the current as my scope only does 2 digits
   
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Peter,

It seems that lower resistance causes lower COP so I would be tempted to go back to your 510 ohm load and confirm the 0.922 COP at 510 KHz.  That is assuming your written 510R means 510 ohms.  Then stay at that frequency and try different loads to get higher COP.  There is bound to be an optimum load where the COP is greatest.

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Something interesting is happening, i just went back and started re doing tests with the 510 ohm load and every test and re test is COP 1 or slightly greater?? at one particular frequency which is the first i went to try.
looking for errors but i am doing exactly what i did yesterday, will keep looking for the error  :P
   

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Something interesting is happening, i just went back and started re doing tests with the 510 ohm load and every test and re test is COP 1 or slightly greater?? at one particular frequency which is the first i went to try.
looking for errors but i am doing exactly what i did yesterday, will keep looking for the error  :P

Dear Peterae.

This might sound like a daft question, but, how different is the weather today ??

Please humour me.   ;)

Cheers Grum.


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Peter
you can remove this post
However I must ask a similar question regarding weather and perhaps
conditioning the environment around your lab.
as you may recall Tinman was getting weather events [rain] immediately after
and in several cases During His Star in a jar experiment which were captured on Video.
Seemed the longer he played with that little Fusion bottle[over time] the more it Manifested.

I know you don't have a Tin roof like he does,and yes I know it rains MUCH more in the UK however it never hurts to Note these things.[temp humidity and pressure]

sorry for the interruption,however those were very funny times...
started calling him RainMan.. 8)

   

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LOL
It was only 3 degrees C when i started work been down there over an hour and the COP>1 has gone, it just went, probably down to temperature change in the scope or something, this is an uncalibrated scope although i did run it through it's own calibration routine last night.

I kept doing checks constantly and checked the cop each time altering the frequency slightly and then my Cops went down here's a list of the tests during this time, i have included the first set of COP=1 scope shot.  O0

362kHz i=65.9 lcv=1.05 load=5.94 Pin=69.19 Pout=69.18 COP=0.999
390kHz i=64.7 lcv=1.05 load=5.97 Pin=67.93 Pout=69.88 COP=1.028
416khz i=63.3 lcv 1.07 load=5.97 Pin=67.73 Pout=69.88 COP=1.032
462khz i=66.8 lcv=1.08 load=5.87 Pin=72.14 Pout=67.56 COP=0.937
390khz i=68.1 lcv=1.05 load=5.80 Pin=71.51 Pout=65.96 COP=0.924
396khz i=68.3 lcv=1.05 load=5.84 Pin=71.72 Pout=66.87 COP=0.932

Also note the little squiggle on the bottom of the sine this is my signal generator getting old and maybe also a problem slightly.
   

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Don't get over excited i have been using 510 as my resistance value for output power calcs but i think when i measured the other day it was about 514ohms and 1%, i was not meant to be any where near COP=1 so have not bothered with the fine stuff so far, i only wanted to start trying different loads and was stopped in my tracks  ;D
   

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Awesome Peter!

What do you think Smudge?  Cold temperature reducing the resistance even more?

Dear All.

Or an increase in humidity !!  ;)

Last year I had a single event where I had an Ionic wind that had my hair standing on end, the humidity changed and the effect was never seen again !!

Cheers Grum.


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Yep it's gone for now.
Been trying different loads, the trouble is that a different load shifts the frequency so i have to adjust the series cap value to bring my primary I & V back in phase.

I also decreased my sig gen drive amplitude to try to get rid of that little glitch at the bottom of the waveform.

Results I've started measuring my load resistance for more accurate results.
Load=1.096 KOhm
load alters frequency
same cap new freq = 271khz cap=28nf
i=68.2 lcv=725mv load=6.68 Pin=49.45 Pout=40.71 COP=0.823

adjusting cap to bring back to 416khz still 1.096KOhm load
416khz cap=15nf
i=61`lcv=1.13 load=8.19 Pin=68.93 Pout=61.20 COP=0.888

new load = 823.1Ohm
416khz Cap=18nf
i=61.4 lcv=1.14 load=7.12 Pin=69.99 Pout=61.59 COP=0.879

new load = 680.1 Ohm
416khz Cap=21nf
i=61.3 lcv=1.09 load=6.33v Pin=66.82 Pout=58.92 COP=0.882

new load = 467.5 Ohm
416khz Cap=27nf
i=63.3 lcv=941mv Load=4.91 Pin=59.57 Pout=51.57 COP=0.866

I should have tried 510 again, it appears that might be a peak in COP.
   

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It looks like the reason for the high cop is the decreased current measurement, therefore i conclude a possibility that the NIR when cold is a lower value. it only takes a few mv drop as this is multiplied by the larger voltage.
It looks like a precision resistance here would be good, but i do not have to to hand.

EDIT
I wonder if i can increase this resistance to 10 Ohm to get an increased current resolution without affecting things too much, if i can get my current measurement into the volts range i would then be able to use Smudges subtraction measurement system.
   
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I think it more likely that your scope calibration is wandering, especially the channel operating at maximum gain (i.e. measuring the NIR voltage).  If you used the same channel for all measurements then although the actual power values may be wrong the ratio forming the COP would not change.  But then you would have to switch the gain and my experience of scopes tells me that action can change calibration so perhaps that wouldn't work.  I see no reason why you should not use a higher value NIR except that it will affect the power you can suck out of your signal generator.

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The fact that the input inductance changes with different load resistors could be significant.  Normally one would not expect this and it seems you have got a 1.8 ratio inductance for a 2.34 ratio load resistor.  If nothing else you may have discovered a method for creating variable inductance without the need for moving parts :D .

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OK will try a bigger NIR

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If nothing else you may have discovered a method for creating variable inductance without the need for moving parts
Sounds good LOL, but is there any way of understanding why?
I wonder if the ratio is related to the primary vs secondary turns ratio.
   
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OK will try a bigger NIR
Sounds good LOL, but is there any way of understanding why?
I wonder if the ratio is related to the primary vs secondary turns ratio.

No.  The effect is related to a time or phase delay between input and output which is exactly what we are looking for to get OU effects.  This delay alters the input current v voltage phase so a resistive load on the output appears at the input to have a reactive component, in this case inductive.  I have shown elsewhere that a magnetic delay acts like a line having a reactive characteristic impedance (whereas classical delay lines have a resistive characteristic impedance) and if you terminate it in a capacitance it reflects as a negative resistance at the input.  So it appears to me that you would benefit from adding capacitance either across or in series with your load.  IOW instead of adjusting your input to get zero phase there by changing the series capacitance there, do it at the output instead.  What I mean is play with different capacity values on the output while still looking at the input phase angle and adjusting it to zero.  You might get some interesting results.

Smudge
   
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If nothing else you may have discovered a method for creating variable inductance without the need for moving parts.

I could be wrong, but I think it is normal for the primary inductance to change with secondary load resistance. Consider the limit case of a ideal transformer with secondary either open or shorted. Primary inductance should go from maximum to zero.

In fact the uncoupled inductance of a transformer can be measured by shorting the secondary and measuring the inductance of the primary. It will show the uncoupled inductance or "leakage" inductance. Coupled primary and secondary inductance disappears with the addition of the short, leaving only the uncoupled inductance.

A magnetic transport delay between input and output negates the ideal transformer scenario and interesting effects may occur, which is what Smudge has said all along.


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Hi ION,

I agree with you there. Attached is a patent with bucking coils where the reactance is controlled by a resistor.
Impedance transforms show that you can vary a pure R and get a pure L or C change in a network in some cases.
This was also used in some transmission line FM modulators where the terminal R was varied to get a variable reactance, which could go from L or C, at the input.
I'll post a scheme on my bench, where just varying the resistance can cause parametric oscillations...

orthofield
   
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It's turtles all the way down
Hi ION,

I agree with you there. Attached is a patent with bucking coils where the reactance is controlled by a resistor.
Impedance transforms show that you can vary a pure R and get a pure L or C change in a network in some cases.
This was also used in some transmission line FM modulators where the terminal R was varied to get a variable reactance, which could go from L or C, at the input.
I'll post a scheme on my bench, where just varying the resistance can cause parametric oscillations...

orthofield

Thanks Orthofield
I'll post my comments on the patent on your bench so not to disrupt this thread
Regards, ION


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Did not get much done tonight.

I fixed a cap value in series with my primary inductor and used a 27nF

I first put a cap box across my 470 ohm load and could adjust the phase of my primary current and voltage as suspected, but when i went to scope across the parallel secondary R&C i had no waveform to measure.

I then tried the cap box in series with the secondary load resistance, again it was possible to adjust the primary phases by adjusting the secondary cap box, nothing really seen, as i now have a series LC on my primary and also a series LC on my secondary i could not fully match the phases on the primary and secondary to do any meaningfull power measurements.

Here's some notes made

if i adjust the secondary series cap value to get voltage across this cap and voltage across secondary load resistance in phase then my voltage across the secondary series cap goes to almost zero, IE very small noisy looking just about recognisable sine on 10mv/div.
at this point my voltage across secondary series cap (just recognisable) is in phase with my primary voltage across the NIR and nearly in phase with my primary lcv but not quiet.

Nothing significant seen.
   
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I was thinking of a small value capacitor across the load, not one that would shunt away all the power.  When you are moving from one experimental set-up to another you are making changes that are too large, I think you need to move in smaller increments.  Like you had a 467.5 ohm load and a 27nF series capacitor on the input to give a COP of 0.866 at 416KHz.  What happens if you add a teeny weeny capacitor across the load and then adjust the 27nF to make good the phase angle there? Does the COP go up or down?  If no change then try a slightly larger one on the load.  Proceed in small steps.  If things are going the wrong way, like COP going down, then reverse the action and do the opposite.  The opposite of adding capacitance is adding inductance.  You must feel your way step by step.

Smudge
   

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Thanks Smudge

Tonight i really wanted to work out if any of my equipment is in calibration.

I have 2 scopes a mains Owon 20MHz scope and the 200MHz Hantek DSO laptop powered i have been using up to now, i prefer the hantek as it is isolated by battery power.

I have suspected my owon was out of calibration because it has a 5V Squarewave gen built in and when i hook that up i get 5.2V Pk-pk.

So tonight i tried using first the Hantek and then the Owon
I changed my NIR to a 10 Ohm carbon film and selected the 10 Ohm using my precision LCR meter for almost exactly 10 Ohm
My load is measuring 516 Ohm and will use this for a while.

I tried the subtraction method and it works pretty good now my current waveform is larger but i am still hesitant because of the 2 digit limitation.

anyway i got 2 totally different results using the hantek & owon, i used just 1 probe to measure each variable

Hantek
1 probe to measure each variable
500KHz 20nF I=636mv LCV=1.03 Load=5.75 Pin=65.51 Pout=64.07 COP=0.978

Using  Owon
500KHz 20nF I=837.1mv LCV=1.202 Load=6.210 Pin=100.6mw Pout=74.7 COP=0.7423

So i then though how can i tell how in calibration each scope is, so i then set my signal generator to 50Hz and put a dvm on it to read DVM 7.33V

and the 2 scopes read as follows

Owon 7.414V RMS

Hantek DSO 7.03V

So it looks like the Owon is fairly close and it does 3 decimal places, so it looks like i now need to start the tests again using the owon.

I will do all the frequency's again to look for a COP peak and then go from there.  O0

I need a new scope really  :)
« Last Edit: 2015-02-26, 18:01:47 by Peterae »
   
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Peter,

Those calibration figures don't account for the different COP's (ignoring your 74.23 COP which is a math error  C.C ) so I think the ground connection to the mains scope might be doing something.  You might track this down by using your Hantek to measure something then just connect the mains scope ground and see if anything changes.

Smudge
   
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