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Author Topic: Bifilar pancake coil overunity experiment  (Read 93417 times)

gyulasun

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Re: Bifilar pancake coil overunity experiment
« Reply #345 on: December 25, 2018, 06:01:43 PM »
Hi Brad,
Very likely there is a parallel resonance developing from the two windings and their dirstributed capacitance at around 11 MHz and the loaded Q of this 'LC tank' can remain high enough to 'produce' the measured 2.25 V across R1. So the input current to this parallel 'LC tank' should be Q times less via the csr so this smaller current can only cause a small voltage drop across the 2 Ohm csr.  Perhaps doing a differencial voltage drop measurement with two probe tips across the CSR can show the 5 to 10 mV voltage drop that cannot readily be seen in the present 2 V/DIV settings.

Gyula

F6FLT

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Re: Bifilar pancake coil overunity experiment
« Reply #346 on: December 25, 2018, 06:50:11 PM »
...
At a certain frequency,I now have 0 volts across my CSR (R2)  :o , but i have 2.25 volts across the load resistor (R1)
...

We are poorly equipped for accurate high-frequency measurements.  Radio amateurs never use scopes for RF power measurements. Just the capacity of the probe disturbs the signal or the magnetic flux through the loop between the tip of the probe and its ground wire (even when the tip is connected to the end of the ground wire, you can measure a significant signal at all), and the cable shielding may be insufficient.

Maybe we should go back to some very basic things. When I needed to measure high frequency voltages in the past, I placed a diode+cap circuit in series on the load and measured the DC voltage across the capacitor.

For example, here, to measure CH2, the diode would have to be connected to CH2 and in series the capacitor C to ground. A germanium or Schottky diode must be used to reduce the voltage drop (0.2->0.3 v vs 0.6 for Si), and the capacitor will be of the order of 0.47µF non-polarized (non-critical value).
The capacitor will charge to the max sinusoidal voltage minus 0.25v. If Vmax is measured, the rms voltage will be Vrms = (Vmax+0.25)/√2. The same method can be used for the 3 points of measurements with the same Diode+C circuit (just use a flying wire soldered to the diode, and use it as a probe). The setup will be much less disturbed than with a scope probe, the parasitic capacitance of the diode being low and the current taken very low because when the capacitor is charged, almost no current is drawn by the diode. And measuring a DC voltage avoids frequency sensitivity dependence, and avoids the long wires of a probe which, although coaxial, are often "porous" to radiation.

The disadvantage is that the measurable voltages must be higher than the diode voltage bias.


Void

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Re: Bifilar pancake coil overunity experiment
« Reply #347 on: December 25, 2018, 06:53:27 PM »
Void

I see no problem here.
Ch1 is measuring the voltage across the function generator.
CH2 is also measuring the voltage across the function generator,minus the voltage drop across a pure resistance(the CSR).
All ground leads are connected at one point,and that is at the ground lead of the function generator.

As i said,i see no problem with the circuit provided,or any of the measuring points.


Hi Brad. Just because someone doesn't see something, it doesn't mean it is necessarily correct. :)
I have suggested how you can test it using a regular transformer to see whether placing the CSR there
with the probe grounds placed where they are gives correct results or not. I am tied up with other
things so can't demonstrate it right now. When Itsu uses his current probe at that same point
it does not have the same problem however, as it is measuring the actual current waveform as it actually is.
Itsu using his current probe at the same location should be showing a more correct phase angle measurement.

Placing the CSR and probe grounds where you have them means you are trying to measure the current phase angle
across both the function generator and the CSR. This is ok for measuring voltages if you take the difference,
but it will be incorrect for measuring the phase angle between the voltage waveform and the current waveform.
Think about it. How can you correctly measure the current phase angle when you are measuring across both the
function generator and CSR at the same time?

I wish a Merry Christmas to everyone!


ayeaye

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Re: Bifilar pancake coil overunity experiment
« Reply #348 on: December 25, 2018, 07:46:36 PM »
It turned out

Yes it turned out without experimenting or anything, it's quite interesting how the things turn out.


tinman

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Re: Bifilar pancake coil overunity experiment
« Reply #349 on: December 26, 2018, 01:14:24 AM »
 author=F6FLT link=topic=17861.msg528771#msg528771 date=1545760211]



Quote
We are poorly equipped for accurate high-frequency measurements.

I would have thought that a 50MHz scope and probes was well within it's limits at 12MHz.

Quote
Maybe we should go back to some very basic things. When I needed to measure high frequency voltages in the past, I placed a diode+cap circuit in series on the load and measured the DC voltage across the capacitor.

Yes,i have also done this in the past,and will give it another shot.

But i agree with void--the way the circuit is,and where the scope probes are placed,we will not see the voltage/current phase offset--the two will always be in phase regardless.

tinman

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Re: Bifilar pancake coil overunity experiment
« Reply #350 on: December 26, 2018, 01:20:54 AM »
Hi Brad. Just because someone doesn't see something, it doesn't mean it is necessarily correct. :)
I have suggested how you can test it using a regular transformer to see whether placing the CSR there
with the probe grounds placed where they are gives correct results or not. I am tied up with other
things so can't demonstrate it right now. When Itsu uses his current probe at that same point
it does not have the same problem however, as it is measuring the actual current waveform as it actually is.
Itsu using his current probe at the same location should be showing a more correct phase angle measurement.

Placing the CSR and probe grounds where you have them means you are trying to measure the current phase angle
across both the function generator and the CSR. This is ok for measuring voltages if you take the difference,
but it will be incorrect for measuring the phase angle between the voltage waveform and the current waveform.
Think about it. How can you correctly measure the current phase angle when you are measuring across both the
function generator and CSR at the same time?

I wish a Merry Christmas to everyone!

Yes,i understand that.
But what i dont understand,as i said back in my test results post,is how can i have a larger current flowing through the load resistor than my FG can deliver,when the transformer(bifi coil) is a 1:1 turn ratio ?.
2nd,how can the voltage either side of the CSR be the same?--not looking at voltage/current phase offset here.

I can place the CSR on the ground side of the FG,and get my phase offset measurement that way-no problem there.


Brad

Void

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Re: Bifilar pancake coil overunity experiment
« Reply #351 on: December 26, 2018, 03:08:14 AM »
Yes,i understand that.
But what i dont understand,as i said back in my test results post,is how can i have a larger current flowing through the load resistor than my FG can deliver,when the transformer(bifi coil) is a 1:1 turn ratio ?.
2nd,how can the voltage either side of the CSR be the same?--not looking at voltage/current phase offset here.

I can place the CSR on the ground side of the FG,and get my phase offset measurement that way-no problem there.


Brad

Hi Brad. I am not sure exactly all that you are doing there, but when dealing with AC circuits
things are not always so straight forward. You have to consider impedances and phase angles
between voltage and current waveforms at the same time, you can't just look at magnitudes of current
and voltage and try to draw conclusions from that. Unfortunately I don't have much time available
right now to look into it more. Good luck with your testing! All the best...


ayeaye

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Re: Bifilar pancake coil overunity experiment
« Reply #352 on: December 26, 2018, 04:19:24 AM »
I'm sorry but, voltage and current cannot be in phase in a circuit where is capacitance. ch1 and ch2 may be almost in phase, but this is only because the voltage on the function generator is much greater than the voltage on the shunt resistor R2. Between ch1 and (ch2 - ch1) there should be a significant phase difference, due to capacitance. In spite that the voltage on the resistor R2 is small, it is important for calculating power, and thus the phase angle between the resistor R2 and the voltage on the function generator, makes a great difference. Thus replacing (ch2 - ch1) with a phase angle just with (ch2 - ch1) provides very wrong result, because all the phase angle factor is then omitted, which in absolute value can be somewhere in between 0.5 and 1. When there though is not much phase difference between the voltage and current in that circuit, then i don't know, one possibility then is that the bifilar coil is really bad, with almost no capacitance between the windings. When this is the case, then so bad bifilar coil sure cannot provide any overunity.


tinman

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Re: Bifilar pancake coil overunity experiment
« Reply #353 on: December 26, 2018, 04:53:27 AM »
Hi Brad. I am not sure exactly all that you are doing there, but when dealing with AC circuits
things are not always so straight forward. You have to consider impedances and phase angles
between voltage and current waveforms at the same time, you can't just look at magnitudes of current
and voltage and try to draw conclusions from that. Unfortunately I don't have much time available
right now to look into it more. Good luck with your testing! All the best...

Void


New test setup and parameters.

I have shifted the CSR to the ground rail.
As can be seen,there is little phase shift between voltage and current,as in the other tests.

I used the scope to calculate all math,including the A-B calculation in the output test to obtain our voltage across R2(the load resistor).
This is so the scope can calculate for phase shift as well.

I have the scope probes set to 10x,and also each channel of the scope,so as the values shown by the scope remain correct.
Setting the probes to the 10x setting allows for very little impact on the circuit values when the probes and ground leads are connected to the circuit.

The first pic shows the circuit,scope probe placement,and resulting scope shot with math calculation.
Our P/in seems to be a steady 109mW as calculated by the scope.
Note the current flowing through R1 is 35.5mA

The second pic shows the circuit,scope probe placement,and resultant VRMS value across the 10 ohm load resistor.
Our P/out is then 1.9vRMS across the 10 ohm load resistor.
P/out=361mW.
Note the current flowing through R2(the load resistor) is then 190mA,and the transformer turn ratio is 1:1  :o

Our COP in this test seems to be 331%  ???


Brad

ayeaye

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Re: Bifilar pancake coil overunity experiment
« Reply #354 on: December 26, 2018, 05:50:34 AM »
New test setup and parameters.

Great. Can you say what coil do you use, so that some can hopefully replicate?


F6FLT

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Re: Bifilar pancake coil overunity experiment
« Reply #355 on: December 26, 2018, 01:49:16 PM »
Hi Tinman

If you move a probe to measure either Pin or Pout, you change the configuration. The capacity of the probes is significant in the process.
The three probes must be connected at the same time. Is that the case?


ayeaye

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Re: Bifilar pancake coil overunity experiment
« Reply #356 on: December 26, 2018, 02:24:39 PM »
Two probes are connected at the same time, as i understand. Two separate measurements, one for measuring input power, and the other for measuring output power. I think this is a good way of doing it, and decreases error.

Why two probes when measuring output power, it's because the voltage on R2 then will be calculated in math channel from two voltages. Good in that is that the oscilloscope's ground is always the same as the function generator's ground.


F6FLT

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Re: Bifilar pancake coil overunity experiment
« Reply #357 on: December 26, 2018, 03:55:05 PM »
Therefore the measure can be irrelevant.
If the scope has only 2 channels, at least a third probe should be always connected to the device and terminated at the other free end by a 1 Mohm resistor.


ayeaye

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Re: Bifilar pancake coil overunity experiment
« Reply #358 on: December 26, 2018, 04:17:57 PM »
at least a third probe should be always connected to the device and terminated at the other free end by a 1 Mohm resistor.

I think he uses 10 times attenuation probes, that's a good way to do it and all i can say by now about it.

I see however one problem.

ayeaye

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Re: Bifilar pancake coil overunity experiment
« Reply #359 on: December 26, 2018, 04:25:09 PM »
at least a third probe should be always connected to the device and terminated at the other free end by a 1 Mohm resistor.

I think he uses 10 times attenuation probes, that's a good way to do it, all i can say by now about it.

Tinman, i see however one problem there.

The voltage calculated on R2 will be inverted too, but this doesn't matter, as what interests us is the square of its rms.

The problem is though, the voltage measured on R1 is inverted, because it is not measured in the right direction, considering the direction of the current. But, the ch2 in the input power measurement is not inverted. Yet, it is used in the math channel calculation not inverted, math channel is calculated simply as ch1 * ch2. One can see it too, ch2 represents current there, and the circuit as it has been known, is capacitive, that is current should precede the voltage, but on that oscilloscope image it lags the voltage.

No hell, it seems that you are right, ch1 * (-ch2) is - ch1 * ch2, also when calculating math channel. Ok, i pointed out that the ch2 is not inverted, as it properly should, we cannot see the channels in the right phases, the calculation though seems to be right.