In order to keep the ZPM replications threads clean I've created this thread when questions can be asked and discussion related to ZPM's functionality can continue.
We can discuss here about the standing waves on ZPM's output, the waves propagation in the core and any subjects not directly related to those ZPM replications.
Regards,
Fighter
| "If you want to find the secrets of the universe, think in terms of energy, frequency and vibration." | ||
| Nikola Tesla | ||
Hi Vasile
You wrote
I searched for it and it is mainly used for dielectrics not metals. In metals, in most of the cases, that dielectric constant is infinity.
I think you are searching for the velocity factor VF also called wave propagation speed in different matérial.
For that u have to use permeability not permittivity who is used for dielectric material.
The permeability is in our spec of the metglas I use and it varies with the gap.
Permittivity is not a criterion in a metglass since it is a conductive material and not an insulator, and that's why it doesn't show it in metglass specs and they do not talk about it.
Basic spec of my MCC320
Jagau
Quoting:Jagau
I think you are searching for the velocity factor VF also called wave propagation speed in different matérial.
Well, no, I am looking for the actual speed of the wave. As I understand , velocity factor VF is a ratio of the speed of the wave compared to the speed if light in vacuum. I could deduce it from velocity factor VF , of course, but that would imply that I already know the velocity factor VF for my aplication which I don't.
For that u have to use permeability not permittivity who is used for dielectric material.
Alright, so you are impling that in the first formula (v = c/√μrk) from the link you provided 2 days ago, instead of k (dielectric constant), I should use Permeability μ (H/m)? That would make the equation as follows: v=300'000'000 m/s over √1'000'000.00 x 1.26 H/m which is 267'262.96 m/s or 267.26296 km/s. So this type of judgement could be a start from which we can find the speed of a wave thru a closed core of metglass or for any other material? Phisical tests need to be done.
Hello everyone.
@ Vasile
I think this image answers your question.
Anything let me know!
YoElMiCrO.
Quoting:YoElMiCrO
Hello everyone.
@ Vasile
I think this image answers your question.
Anything let me know!
YoElMiCrO.
Thank you for the effort, but please clarify the following:
1)The formula that I am supposed to use for measuring the speed of the electromagnetic wave in the core is (1/2 le@td) ?
2) What is "le", what is "@" and what is "td"?
3) I am looking at your osciloscope diagram (the one in the middle). Let us suppose the power source has 12 V. On the moment of switch on the voltage drops because we have a load in the system (Inductance 1, L1). After some time it stabilises at 10V lets say, thats why we have the straight line. Looking on CH2, we notice that the waveform has a delay in appearing, meaning it does not appear instantly. So the first dot when calculating "td", is when the secondary voltage waveform starts appearing?. Also what is the second dot? Is it the middle voltage moment of the rising voltage waveform in the secondary?
4)What is N1, N2 and B1? And also the formula N2/N1*B1
Regards.
Hi Vasile
Le is the magnetic length of the core in question.
Td is the dead time, this indicates the time it takes
in appearing a current in the secondary.
For example...
Imagine a toroidal core that has 200mm of actual magnetic length
according to its manufacturer and any material.
Now you make the switch short for 10uS.
You always measure between the means of the waveforms.
Imagine that the measurement of the time it takes to induce a current in
the secondary is 120nS.
That means that the magnetic wave took 120nS to travel 100mm...
If you want to calculate the time it takes to travel 1 meter...
(1000/100)*120=1200nS=1.2uS.
Note: Now I saw that channel 1 of the oscilloscope is at B1 and has
that being in the Sw, excuse me, later I fix it.
YoElMiCrO.
Quoting:YoElMiCrO
That means that the magnetic wave took 120nS to travel 100mm...
So that would imply that the speed of the wave in the core is 0.1m/0.00000012s=833'333.00 m/s.
Why did you use only 100mm for this type of calculation if the total lenght of the core is 200mm? Doesn't the wave travel all the cores lenght (200mm) before it induces something in the secondary? What is the reasoning for the halving?
Hello everyone.
@ Vasile.
If you look closely at one winding is facing the other, that is, at 180 degrees.
That means that when the primary is activated, the wavefront
magnetic reaches the secondary in the time shown by the oscilloscope.
Since the secondary is geometrically in front of the primary, this front only
It takes half the magnetic length to get to the secondary.
There is no more calculation than that!
In the example I gave, the speed you calculated the number is wrong, just that.
It is the same to say that 1/[(1000/100)*1.2*10-6]=83 333m/s.
That's the speed of propagation of the magnetic wave for that
Material/Geometry of the core in question.
I hope it helps.
YoElMiCrO.
Quoting:YoElMiCrO
It takes half the magnetic length to get to the secondary.
Alright, this seems logical.
In the example I gave, the speed you calculated the number is wrong, just that.
It is the same to say that 1/[(1000/100)*1.2*10-6]=83 333m/s.
What do you mean the number is wrong? You said " the magnetic wave took 120nS to travel 100mm...". 100mm = 0.1m and 120ns = 0.000'000'120s. Speed is distance/time(m/s) so we have 0.1/0.000'000'120=833'333.33 m/s. What is wrong in this calculation?
The speed that Yoelmicro has calculated for you is correct and is in meters per second = 83.333 meters per second this speed does not change, only the time traveled can be shortened.
Your mistake, you calculated the speed in tenths of meters per second, bring that back to meters per second, you will have the correct answer.
Jagau
Quoting:Jagau
Your mistake, you calculated the speed in tenths of meters per second, bring that back to meters per second, you will have the correct answer.
Jagau
What? You must be joking. What do you mean I calculated in tenths of meters per second? 100mm is 0.1m. 0.1m is not tenths of meters, it is 0.1 METRES. I don't get your logic.
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