STEORN DEMO LIVE & STREAM in Dublin, December 15th, 10 AM

[Omega_0]

@Omega_0,

I used my Thermometrix thermometer (0.0001oC precision) and first measured the temperature near the device. Ten measurements taken at 1min  interval gave a mean value of 24.4173 +- 0.0919oC. Then I wound around the temperature probe a 0.087Ohm resistor and soldered it into the setup as Rin while running the device at 1Hz. The average of ten measurements taken at 1min interval now is 25.5343 +- 0.0722oC. So, as expected, we have a slight increase (on the order of 1oC) in temperature of Rin. This cannot, however, explain away the effect.

Well that's correct. Still a quality shunt will remove all doubts and will also serve as a cross check for the probe, when you get them.

And what do you think about skin effect. I posted something about it above, before the ice storm hit....

[IceStorm]

Icestorm, its important that you understand power correctly before you venture into OU (or even non-OU systems).

http://en.wikipedia.org/wiki/AC_power#Basic_calculations_using_real_numbers

I will quote here :
"For a perfect capacitor or inductor there is no net power transfer, so all power is reactive."

More
http://www.allaboutcircuits.com/vol_2/chpt_11/2.html


We know that reactive loads such as inductors and capacitors dissipate zero power, yet the fact that they drop voltage and draw current gives the deceptive impression that they actually do dissipate power. This “phantom power” is called reactive power,


# Power dissipated by a load is referred to as true power. True power is symbolized by the letter P and is measured in the unit of Watts (W).
# Power merely absorbed and returned in load due to its reactive properties is referred to as reactive power. Reactive power is symbolized by the letter Q and is measured in the unit of Volt-Amps-Reactive (VAR).
# Total power in an AC circuit, both dissipated and absorbed/returned is referred to as apparent power. Apparent power is symbolized by the letter S and is measured in the unit of Volt-Amps (VA).


The equation you posted in also not totally correct. The impedance is
Z^2 = R^2+X^2
and V=I x Z
(note that these are vectors, except R which is scaler)

you are a bit confused again i think. Power = I^2 * R, Omnibus was right in his equation, his was talking about power , look at Ohm law. When you state Z^2 = R^2+X^2 you are right , R is a scalar since its static, but that represente A LOAD , X represent the Reactance, so the impedance of the coil, Just ask you a question, whats the unit of the Reactance ? answer : OHM , so the total impedance on the primary side in his schematic is Rin + XL = Z, since he already know the amp draw , the power used can be derived with I^2 * Z = Power, and the power used is DIRECTLY proportional to the TOTAL impedance.

Exemple time:
you have 2 coil , each coil is 250mH, the first one use really small wire and the DC resistance is 15 Ohm , the second Coil use big heavy wire and have a DC resistance of 0.001 Ohm, the amp draw will be the same for each one under the same frequency because the impedance will be the same, so ignoring the impedance when you try to figure out the Power used is .....

Best Regards,
IceStorm

[Omnibus]

@Omega_0,

I'm just coming back from a discussion with a prominent colleague, a professor at a leading university. What I heard was that there is a culture among professionals to always consider impedance when they talk about resistance in AC cases. Just as @IceStorm tends to think. That's incorrect but that's the culture in these circles. Pure Ohmic resistance is only considered when measured at 0Hz, otherwise a distinction is never made between the different components of the impedance and talk is always about the concrete models of that impedance (are inductances, capacitances and active resistance connected in series or in parallel or whatever else way you can propose and sustain it). That approach has to change, of course, because we're only interested in the Joule heating in this very case, and a current probe will resolve it at once. So, the importance of a current probe is greater than it appeared initially. I learned also that power balances of transformers (although teaching the theory of transformers is their primary job) never involves studying rigorous power balances but students are only presented with only approximate models. I have a strange feeling that this is another instance of suppression at play here but let's not distract from the main issues of discussion. I'm now eagerly waiting for the current probe due to arrive on Wednesday (hopefully the power supply too). Tomorrow I'm expecting the arrival of the precise 0.001Ohm shunt. I will also start the preparations for calorimetry. As usual, I'll post the results from my studies as soon as I obtain them. I guess that's all from me for today.

[lumen]

It looks to me like you are only measuring the actual input with no way to know the difference between reactive and dissipated power.

Using the circuit below, (R primary) is not a known value at every frequency. (R in ) will however show the actual current draw but not actually the current flowing through the primary since it will also show current from out of phase reactance of the primary.

At very high frequency, the primary would work as a choke and no current would pass through the primary except for some DC offset.

I would think you need a resistor on the ground leg of the primary and CH3 of the scope to show actual current passing through the primary and even then the channels CH1 and CH3 may need to be summed to find the actual non reactive current in the primary. DC coupling may also need to be removed between the pulse generator (series capacitor) and the circuit to remove any DC coupling if this does not already exist in the pulse generator output.

I understand what you are thinking and it seems to make sense, but to view the resistance of (R primary) as constant, could be misleading the calculations.




   

[Omnibus]

@Omega_0,

Forgot about the skin effect. I think you're right, it may play a role which is important for Rin only. For Rprimary, even if that effect is tangible won't change the OU conclusion because the scope is measuring what it really sees as I and V. Again, this as well as @lumen's concern  will be taken care of by the current probe. So, let's wait and see what those experiments will show. Like I said, I'm preparing also for calorimetry but there is a slight concern that it may not be conclusive. Imagine if the reaction of the core is such that it cools down causing the OU effect through the violation of second thermodynamic law. Then we'll see no effect calorimetrically and yet the OU will be real. Anyway, at this point I have some more practical things to deal with. Will keep you posted.