Bifilar pancake coil overunity experiment

[itsu]

I did point out that measuring without the input transformer has its own problems as well.
Also, are you guys trying the test I mentioned to move the scope probe leads around when
doing your measurements to see if the phase difference shown on the scope shifts around when
the scope probe leads are moved to different positions? Ignore this check at your own peril.

Itsu, when you measure the input current with your current probe, if the current probe is attached
to the same scope that you are measuring the input voltage waveform with, then the scope
ground provides the common point of reference between channels for doing the phase measurement.
Would you agree? You wouldn't be able to do phase measurements if that were not the case.

Hi Void,

yes, the current probe is attached to its current controller which is attached to (in my case) CH4.
So yes , all probes have a common ground.

But the voltage probe with its ground lead forces that probe to "look" only to the signals (and phase)
between the probe tip and its ground (CH2 to ground = R2 + FG), while the current probe looks at the whole branch
it is in, so L1, R2 and FG (current probe placed between FG + and R2).

Below screenshot shows the difference in phase when i remove the CH2 ground from reference ground (white trace)
to just before R2 (blue trace), both compared to the current probe trace (green) where i trigger on.

It flips from -52° phase difference to (almost) 0°.

Itsu

[Void]

But the voltage probe with its ground lead forces that probe to "look" only to the signals (and phase)
between the probe tip and its ground (CH2 to ground = R2 + FG), while the current probe looks at the whole branch
it is in, so L1, R2 and FG (current probe placed between FG + and R2).

Below screenshot shows the difference in phase when i remove the CH2 ground from reference ground (white trace)
to just before R2 (blue trace), both compared to the current probe trace (green) where i trigger on.

It flips from -52° phase difference to (almost) 0°.

Itsu

Hi Itsu. Sorry, I am not following you. You should not move the Ch2 ground from the common ground reference point for
all the probes to just before R2, as all probes must have the same ground reference point, so, I am not following what
you are trying to do/demonstrate there by moving the Ch2 ground. You would have a ground loop if you did that. Maybe
I am misunderstanding you.

I would be inclined to go with the current probe measurement and not use the CSR at the input (in this particular measurement arrangement),
but do try moving the scope probe leads around (both current and voltage probe leads) when doing these measurements to see if that impacts
the phase angle measurements. If it does, then the phase angle measurements for certain can't be trusted if you see that happening.

[itsu]

Void,

yes, as i said earlier, i am struggling for words to explain.

as long as i use only 1 probe (blue in this case), i can put its ground lead where ever i want.
I just want to show that by moving the ground lead of the CH2 blue probe, its phase flips from -52°
out of phase with the current probe (green) signal to IN phase with the current probe signal.

I otherwise cannot explain why by using a different measurement setup, my circuit COP halfs from COP=1
to COP=0.5

Itsu

[F6FLT]

You are telling without knowing. That's not saying that anything provides OU.

I haven't not to know that.
"What is asserted without proof can be denied without proof".
Euclid
This statement from a great thinker saves us from wasting time with those who talk nonsense while they have the burden of proof. Thanks a lot, Euclid! 

[Void]

Void,

yes, as i said earlier, i am struggling for words to explain.

as long as i use only 1 probe (blue in this case), i can put its ground lead where ever i want.
I just want to show that by moving the ground lead of the CH2 blue probe, its phase flips from -52°
out of phase with the current probe (green) signal to IN phase with the current probe signal.

I otherwise cannot explain why by using a different measurement setup, my circuit COP halfs from COP=1
to COP=0.5

Itsu

Hi Itsu. I think I understand what you mean now. You are changing the ground reference point
for the scope measurement across the CSR when you do that, so not surprising that the measured phase
angle shifts relative to the current probe.

At any rate, I would be inclined to go with using your current probe and not use the CSR at the input in
that particular test arrangement. Have you tried my suggested check to move the scope probe leads around
when doing these measurements to see if moving the scope probe leads (both current and voltage probe leads)
has any effect on your phase angle measurements? I have found this can sometimes be a major problem in this
type of setup with big coils at higher frequencies.

One way to possibly make the measurements more reliable in this type of setup is to place the test circuit with
coils inside a full metal enclosure (all sides enclosed), and just have connectors on the metal enclosure for connecting
the scope probes. The metal enclosure should be grounded to the common ground point for the whole test circuit.
This will help to stabilize the circuit against stray capacitances, and will help to contain the EM fields around the coils inside
the enclosure, but that is a lot of extra work. It might be necessary for testing with this circuit arrangement however, to get more
reliable results. There may be other factors affecting the measurements as well however, such as unaccounted for
capacitive coupling that is bypassing measurement points to some extent. 

P.S. There is another aspect to this that can significantly affect the efficiency measurement results.
The input transformer can act as a impedance changing transformer, depending on its winding ratio,
and changing the impedance differences between sections of the circuit can have a significant impact
on overall circuit efficiency. Whether impedances match closely or not between different sections of the circuit
can change the circuit efficiency considerably.