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Author Topic: The bifilar pancake coil at its resonant frequency  (Read 567370 times)

synchro1

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1020 on: April 18, 2017, 11:49:32 PM »
@Mags,

If you have an Inductance meter, try hooking it up to the coil while you run your frequency scan, and see at exactly what frequency the Inductance drops to zero. Any reading that appeared with a minus sign in front would indicate the presence of a magnetic field.

TinselKoala

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1021 on: April 19, 2017, 12:01:48 AM »
The coil field increase factors directly into electrical power units that can be deducted from the input for an accurate COP. A negative Henry is the measure of the coil's magnetic field strength! Joseph Henry's formula of Inductance allows us to measure the field strength in units of negative inductance, and give that an equivalent value in electrical power units.

I just love it when you refute your own nonsense yourself, with information you find when finally googling the terms you misuse so flagrantly.
Nowhere in those various equivalent expressions for the Henry does an expression for ELECTRICAL POWER exist. ELECTRICAL POWER is measured in WATTS, the units of which are Joules/second. You will note that I TOLD YOU several times earlier that the Henry can be expressed as Joules/ampere2, which DOES appear in that chain of equivalent expressions. If a "negative henry" is "equivalent" to "watt-hour" as you have repeatedly claimed.... since the watt-hour is an expression of ENERGY NOT POWER...  you once again are getting all tangled up with your own claims and the solid refutations from the material you yourself post.

TinselKoala

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1022 on: April 19, 2017, 12:08:16 AM »
@Mags,

If you have an Inductance meter, try hooking it up to the coil while you run your frequency scan, and see at exactly what frequency the Inductance drops to zero. Any reading that appeared with a minus sign in front would indicate the presence of a magnetic field.

And if you damage your delicate inductance meter by applying a voltage from your FG while doing this, I'm sure Synchro will happily pay for a replacement. Won't he?

The presence of an alternating magnetic field is indicated by the ability of the coil to induce an alternating voltage in a nearby coil... something that has been shown to occur throughout the frequency ranges scanned. Of course one needs to be able to interpret oscilloscope screens to see this fact.

Furthermore, the inductance of coils we are testing never "drops to zero" and this is clearly indicated by the results of the frequency scans.

TinselKoala

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1023 on: April 19, 2017, 12:17:22 AM »
TK

Are you able to power a small load(E.G an LED) from a pickup coil(secondary) placed on top of the BPC,without it effecting this zero voltage across your CVR.?


Brad

No, when powering a LED load at the TBF's resonant frequency the CVR voltage trace does not quite "flatline" any more, it indicates about half a milliamp at flattest. This is with just enough amplitude of the signal input to the TBF to produce a slight glow in the LED. Of course if I go off the resonant frequency I can get a lot more power to drive the LED much more brightly from the pickup coil, especially if I go to the pickup coil's own resonant frequency, as the previous frequency scans show. The CVR trace grows then too. 

Here's a scopeshot of the "flattest" CVR line while powering a slightly glowing LED from the pickup coil. Yellow=CVR trace, with the current value shown being a little smaller than actual because the scope thinks I'm using a 10 ohm CVR but actually I'm using 9.4 ohms. Blue = across LED and pickup coil.


Magluvin

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1024 on: April 19, 2017, 12:42:53 AM »
No, when powering a LED load at the TBF's resonant frequency the CVR voltage trace does not quite "flatline" any more, it indicates about half a milliamp at flattest. This is with just enough amplitude of the signal input to the TBF to produce a slight glow in the LED. Of course if I go off the resonant frequency I can get a lot more power to drive the LED much more brightly from the pickup coil, especially if I go to the pickup coil's own resonant frequency, as the previous frequency scans show. The CVR trace grows then too. 

Here's a scopeshot of the "flattest" CVR line while powering a slightly glowing LED from the pickup coil. Yellow=CVR trace, with the current value shown being a little smaller than actual because the scope thinks I'm using a 10 ohm CVR but actually I'm using 9.4 ohms. Blue = across LED and pickup coil.

So in your first paragraph you are saying you get more induced into the secondary by not being at resonance with the input than if you are at resonance? That was the statement before especially with a freq of the sec res freq.


Are the bumps showing the 'off res freq' you are using?

Mags

Magluvin

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1025 on: April 19, 2017, 03:50:15 AM »
So in your first paragraph you are saying you get more induced into the secondary by not being at resonance with the input than if you are at resonance? That was the statement before especially with a freq of the sec res freq.


Mags

Hmm, well i just have to see for myself with my setup.  I just dont get that. 

Will see.

Mags

TinselKoala

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1026 on: April 19, 2017, 04:23:17 AM »
So in your first paragraph you are saying you get more induced into the secondary by not being at resonance with the input than if you are at resonance? That was the statement before especially with a freq of the sec res freq.

Yes. Take a look again at the frequency scan attached below. You can see that the most voltage induced in the "secondary" happens at its own resonant frequency (great purple peaks at about 1.24 MHz) not at the resonant frequency of the TBF "primary" (the frequency of the "notch" in the CVR yellow trace at 273.2 kHz).

Quote


Are the bumps showing the 'off res freq' you are using?

Mags

That scopeshot was taken at the resonant frequency of the TBF "primary" (look at top right for the frequency counter measurement) which is where the CVR trace flatlines under no load condition. I think the bumps in the Blue trace are the "secondary" trying to resonate at its own frequency of about 1.24 MHz, a bit over 4 times the primary resonant frequency. Because of the way I had the LED oriented polarity wise, the LED is turning on at the flat bottom of the Blue trace and the top parts with the bumps are when the LED is reverse-biased and not lit. I think.


TinselKoala

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1027 on: April 19, 2017, 04:46:53 AM »
I would just like to point out something here.

The Henry, denoted by H, is a scalar quantity and is the measure of inductance in the SI system.

On the other hand, H is a vector quantity that denotes the magnetizing field strength, and is not named after Joseph Henry and is not a measure of inductance. Its common units are Amperes/Meter. It is most certainly NOT equivalent to H, the Henry, the measure of inductance. The symbol "H" was assigned to this quantity in about 1850 by Lord Kelvin, who apparently picked the letters B and H at random.

Furthermore, there is a difference between the "negative" of a quantity and the "inverse" of a quantity.

http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magfield.html
https://en.wikipedia.org/wiki/Magnetic_field

MileHigh

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1028 on: April 19, 2017, 06:36:53 AM »
To help understand this stuff, I am going to take a crack at a mechanical version of the parallel LC circuit acting as an infinite impedance at resonance.  However, next posting because this page has the wide sickness.

MileHigh

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1029 on: April 19, 2017, 06:37:51 AM »
Are we on a new page?   Okay a fresh start on a new page.

We know the parallel LC resonator acts like an infinite impedance at resonance.  That means no power flows trough it, and therefore it is a no load device.

Imagine a large vertical spring on the floor with a heavy weight on top of it.   When you push down on the weight and let go the system resonates up and down at it's natural frequency.

Let's suppose the natural frequency is quite low, say two cycles per second.  Now imagine a person siting next to the resonating weight and spring system.  Imagine his coordination is very good and his hand is over the weight and moving up and down in perfect sync with the oscillating weight.

So, what do you see?  It _looks_ like the person is making the weight resonate up and down, but it's a fake-out.  The person is not applying any pressure on the weight at all, the system is self-resonating.  The person is not doing any work at all.

The person's oscillating arm is the function generator set on sine wave.  To be specific the _velocity_ of the person's hand is in the form of a sine wave which is like the voltage, and if he had to apply pressure to the weight, that would be the current.

Now, let's make one concession to the real world because we know that the resonant system will decay over time if you don't put some mechanical power into it.  Let's ignore air friction and focus on the spring as a lossy spring.  The spring will heat up just like the proverbial bending of the coat hanger and that friction will dampen the resonant oscillation.

So in the "real world" as the person's hand follows the up and down sine wave motion of the weight, every now and then he applies just the tiniest amount of pressure to the weight to ensure that the resonance remains at the same amplitude.

So when the person puts just a little touch of mechanical power in the resonating spring and weight system to keep the amplitude stable and compensate for the resistive looses in the spring, likewise the function generator puts a little touch of electrical power into the parallel LC resonator to compensate for the resistive losses in the inductor.

That gives you a basic idea of what is talking place.  However, it really needs work to get it 100% bang on and I am not going there.  Likewise I am not going to delve into a mechanical equivalent of a series LC resonator.

The big takeaway is this "no power flow/no load" condition all only works at the resonant frequency where the excitation (moving hand) is a perfect sine wave.  If you deviate from that set of conditions it simply doesn't work.

synchro1

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1030 on: April 19, 2017, 01:13:14 PM »
I just love it when you refute your own nonsense yourself, with information you find when finally googling the terms you misuse so flagrantly.
Nowhere in those various equivalent expressions for the Henry does an expression for ELECTRICAL POWER exist. ELECTRICAL POWER is measured in WATTS, the units of which are Joules/second. You will note that I TOLD YOU several times earlier that the Henry can be expressed as Joules/ampere2, which DOES appear in that chain of equivalent expressions. If a "negative henry" is "equivalent" to "watt-hour" as you have repeatedly claimed.... since the watt-hour is an expression of ENERGY NOT POWER...  you once again are getting all tangled up with your own claims and the solid refutations from the material you yourself post.

@Tinselkoala.

What do you call an ampere second at one volt? Joseph Henry defines the H as The amount of inductance (Coiled wire) it would require to generate one volt by varying a current by one ampere per second across the inductor.

Definition of Watt Hour:

"A Watt Hour is a measure of electrical energy equivalent to a power consumption of one watt for one hour".

You falsely state that a "Watt Hour" is energy but not power, when the truth is it's equal to power!

You twist the other very valuable word to cause the kind of Gnomic mischief you're notorious for? Who can find a negative when it's past zero? Coupled with compulsive adolescent insults and abuse, snickering to yourself, through your schlag covered face.

synchro1

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1031 on: April 19, 2017, 01:35:07 PM »
Times up: The ampere second at one volt is a "Watt Second". A watt second times seconds and minutes (60)x(60)= 3600 watt seconds=One "Watt Hour". That's equal to a consumption of one Watt for one hour. A "Watt Hour" equals 3600 Coulombs.

Electrical power input to an induction coil generates a magnetic field. The field force measured in a coil of 1 Henry with one watt hour of power stored in it's magnetic field equals 1 Tesla of magnetic flux density.

synchro1

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1032 on: April 19, 2017, 02:16:34 PM »
@Tinselkoala,

You need to start with the "Magnetic Coulomb" law:

"In physics, the magnetic Coulomb law is the magnetic equivalent of the electric Coulomb law".

"The magnitude of the electrostatic force of attraction between two point charges is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them".

synchro1

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1033 on: April 19, 2017, 02:38:09 PM »
@Tinselkoala,

Ponder on this:

"The unit for magnetic reluctance is inverse henry, H−1".

"Magnetic reluctance, or magnetic resistance, is a concept used in the analysis of magnetic circuits. It is analogous to resistance in an electrical circuit, but rather than dissipating electric energy it stores magnetic energy".

nelsonrochaa

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Re: The bifilar pancake coil at its resonant frequency
« Reply #1034 on: April 19, 2017, 02:49:25 PM »
@Tinselkoala.

What do you call an ampere second at one volt? Joseph Henry defines the H as The amount of inductance (Coiled wire) it would require to generate one volt by varying a current by one ampere per second across the inductor.

Definition of Watt Hour:

"A Watt Hour is a measure of electrical energy equivalent to a power consumption of one watt for one hour".

You falsely state that a "Watt Hour" is energy but not power, when the truth is it's equal to power!

You twist the other very valuable word to cause the kind of Gnomic mischief you're notorious for? Who can find a negative when it's past zero? Coupled with compulsive adolescent insults and abuse, snickering to yourself, through your schlag covered face.


I think that exist a misunderstood or a fault of communication about this subject . Watt and Wh have different definitions .

A watt (W) is a unit of power, and power is the rate at which energy (joules) is produced or consumed in a second .

A watt-hour (Wh) is a unit of energy; it’s a way to measure the amount of work performed or generated  in one hour
 joules X time 3600S =Wh   

watt-hours measure amounts of energy for the specific period of time of one hour, and watts measure rates of power at a moment in time.

Just to clarify

Nelson Rocha