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Author Topic: Tesla's "COIL FOR ELECTRO-MAGNETS".  (Read 390982 times)

Offline fritz

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #90 on: May 14, 2013, 04:18:53 PM »
(...) if we want it to turn on fast (current to flow as quick as possible) then we need to look at cancelling it's self inductance in order for it to turn on quicker. Wouldn't we ?

As already pointed out - I think the technical relevance of that tesla patent is about "these" types of coils - and it´s no practical approach for quick switching due to the ohmic losses in such coil.
Its all about about no cap and less isolation distance needed, I suppose.

The usual way for a "quick turn on" is to use high voltage and current control.
If you want a stepper motor with high speed and torque you typically use for example a "3V"  motor and operate it with 48Volts.
The voltage for such motors is rated for DC losses at 3Volts. If you have a pulsed driver with 48Volts in chopper mode - and limit the current+adjust the chopper timings to keep the ohmic losses within the same range as operated with "pulsed 3V DC".
A "3V" motor has lower DC resistance and  lower inductivity than a motor rated for higher voltages (DC).

So I would design towards low inductance, low DC resistance, high voltage and smart switching/chopping.
For half-bridge designs, I would use a "snubber" to limit "turning off" time.
With an H bridge - you could feed the energy back into the caps of the powersupply.


rgds.

 

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #90 on: May 14, 2013, 04:18:53 PM »

Offline synchro1

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #91 on: May 14, 2013, 06:32:22 PM »
(http://www.overunity.com/Themes/default/images/post/xx.gif)Re: Magnetic Overunity Motor Design« Reply #4 on: August 09, 2012, 03:48:10 AM »Quote
Update #1:

Wound the coils in bifilar manner; windings are parallel.  Each coil is 1000 turns, 9.1 Ohms.  My goal was to create the same number of Ampere turns with less resistance and lowered voltage.  What I discovered is that I was way wrong about how it would actually work.  So this is for all those aspiring folks out there: Powering the 2 coils in parallel DOES NOT double the turns just because you have two coils wound together, it only allows more current flow at the same voltage because of the lowered resistance.  Winding bifilar coils and connecting them in parallel is the same as using a larger gauge wire.

With this letdown under my belt there is a silver lining, sorta.  Powering them in series does make a stronger electromagnet.  Not sure why yet but it does.  This assertion is based on force measurements I made between the bifilar coil and a single strand wound coil.  And according to Tesla's patent, it allows extra storage of "magnetic" field energy (2X when compared to a single strand coil of the equivalent turns),!

Offline gyulasun

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #92 on: May 15, 2013, 12:41:11 AM »
As already pointed out - I think the technical relevance of that tesla patent is about "these" types of coils - and it´s no practical approach for quick switching due to the ohmic losses in such coil.
Its all about about no cap and less isolation distance needed, I suppose.
.....


Hi Fritz,

I agree with most what you mentioned in your above post, except for what I quoted in bold. The reason is that Tesla wrote in his patent:

"I have found that in every coil there exists a certain relation between its self-induction and capacity (i.e. capacitance) that permits, a current of given frequency and potential to pass through it with no other opposition than that of ohmic resistance, or, in other words, as though it possessed no self-induction."

So he drove the series bifilar coil with an AC current whose frequency was the same as the self resonant frequency of his series bifilar coil and this way the usual inductive reactance every coil manifests (away from resonance)  did not oppose the initial input current: the input current was determined only by the coil's ohmic resistance in his circuit.  So the advantage of his coil construction was two fold: he did not have to use a dedicated HV capacitor for tuning the coil and the other advantage was the input current did reach its maximum value possible without delay, dictated by the ohmic coil wire resistance only. This latter is not the case for coils operated (i.e. pulsed) below their own resonance frequency: current can only increasy exponantially during the 5*L/R time duration.

rgds,  Gyula

Free Energy | searching for free energy and discussing free energy

Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #92 on: May 15, 2013, 12:41:11 AM »
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Offline gyulasun

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #93 on: May 15, 2013, 12:53:07 AM »
(http://www.overunity.com/Themes/default/images/post/xx.gif)Re: Magnetic Overunity Motor Design« Reply #4 on: August 09, 2012, 03:48:10 AM »Quote
Update #1:

Wound the coils in bifilar manner; windings are parallel.  Each coil is 1000 turns, 9.1 Ohms.  My goal was to create the same number of Ampere turns with less resistance and lowered voltage.  What I discovered is that I was way wrong about how it would actually work.  So this is for all those aspiring folks out there: Powering the 2 coils in parallel DOES NOT double the turns just because you have two coils wound together, it only allows more current flow at the same voltage because of the lowered resistance.  Winding bifilar coils and connecting them in parallel is the same as using a larger gauge wire.

With this letdown under my belt there is a silver lining, sorta.  Powering them in series does make a stronger electromagnet.  Not sure why yet but it does.  This assertion is based on force measurements I made between the bifilar coil and a single strand wound coil.  And according to Tesla's patent, it allows extra storage of "magnetic" field energy (2X when compared to a single strand coil of the equivalent turns),!

Hi synchro1,

Unfortunately I have to deduce from his posts that when travin69 changed the coils to bifilar wound types his single wound coils earlier had also 1000 turns??  Because if the single coils had 1000 turns and he wound the bifilar coils with also 1000 turns to create the same number of Amper turns, then it is obvious he got stronger electromagnet when powering the bifilar coil in series!  2 x 1000 turns makes stronger electromagnet than 1 x 1000 turns. 
(When powering the 2 x 1000 turns in parallel, he noticed it was the same as using a thicker wire to make the coil. First he wished to make the bifilar coil with comparable Amper turns to the single coil, hence the 1000 turns in parallel bifilar.)

Gyula

Offline synchro1

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #94 on: May 15, 2013, 04:14:22 AM »
                   "Based on the force equation for electromagnets and coils, force increases based on the face area of the poles"

                               This force equation might help explain one advantage of Tesla's pancake design for electromagnets..
 
He goes on to describe his experiment to TK:
 
 
Tinsel:

I wound two seperate wires simultaneously parallel to each other.  What I was led to believe (stupid me) was that if I powered them in parallel, I could add each coils windings together and halve the current.  BKGD: Each coil is 200 ft of 26AWG wire and makes about 1100 turns or so on the coil.  This in fact is false and to double the ampere turns, i have to double the amperage.  Since I am trying to keep my I2R losses to a min, I am just going to wind them IAW Tesla's patent.  Currently, they are about 0.925" long.  I want to get them down under 0.75" if possible.  I have heard that as the windings get further away from the core, the outer windings aren't as coupled to the core.  I have not seen this actually printed in any of the books I have read. 

After some recent research, I have discovered that some coils are wound with different gauge wire and wound more like a transformer with windings on top of windings.  I would like to put 22 AWG wire on first, say 300 turns, then finish it off with 26 AWG wire wound on top, like 700 turns.  If I am not mistaken, the outer coil's magnetic field should concentrate the inner field and result in a more uniform magnetic field.  This method is done at many of the research labs to get magnetic fields in excess of 30 Teslas

Free Energy | searching for free energy and discussing free energy

Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #94 on: May 15, 2013, 04:14:22 AM »
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Offline MileHigh

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #95 on: May 15, 2013, 06:28:37 AM »
I am assuming a lot of you know the Hyperphysics web site.  It's a great resource.

http://hyperphysics.phy-astr.gsu.edu/hbase/hph.html
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/indcur.html#c2
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/indsol.html#c1

Here is something to ponder:  When you look at a coil, you can separate it into individual loops of wire.  Each loop will generate a magnetic field that looks like the familiar toroid that extends out to infinity.  So you simply add the magnetic fields together from each loop to get the true magnetic field generated by the coil.  The only tricky thing to remember is that the magnetic field is represented by a vector that has both magnitude and direction.  Therefore all of the additions are vector additions.

And when you strip it down to it's bare-bones reality, that's all there is.

If there is a core inside the coil, then each loop will tend to have more of the magnetic flux it generates travel through the core.  If the windings are many layers thick, the outer windings see a core that is further away with some "air" in between.  Since the "air" is much less conducive to the passing of magnetic flux than the core, almost all of the magnetic flux generated by the outer loops will also travel through the core.   So there is very little difference between a loop that's wrapped directly around the core material and an outer loop that's effectively 1/2 inch away from the core.  Both loops will contribute a nearly equal amount of magnetic flux through the core.  Naturally the outer loop will contribute a bit less because a very small amount of flux will flow through the "air gap."

You can use the terminology "lossy" for the outer loops in the sense that a very small amount of the flux they generate does not flow through the core.  So that's arguably "lost" flux.

What that means is many "exotic" coil winding schemes are exercises in futility.  I know I am using somewhat strong terms but it's true.  All the circuit cares about with respect to a coil is its inductance.  You can wind a coil in many fancy ways.  ZeroFossilFuel made "hemisphere" coils.  No doubt the magnetic field pattern generated by the hemisphere coils will be a bit different.  You can visualize it in your head, each loop creates the toroidal magnetic field pattern.  Some are larger than others and they are also offset from each other.  Big deal, you add up all of the magnetic field vectors and you are still left with an inductor, or an electromagnet.  If you plug the coil into an electrical circuit, the shape and the winding pattern of the coil means essentially nothing.  All that the circuit sees is that the coil has an inductance.  We are going to assume that the capacitance of the coil is minuscule and irrelevant and does not affect the operation of the circuit.

Now, think of some exotic coil winding configuration being used as a drive coil in a pulse motor.  Same deal, all the pulse motor cares about is that the coil has a certain inductance and generates a magnetic field.  Think of all the pulse motor clips with exotic drive coil winding schemes and break them down in your mind into individual turns, and add the magnetic field generated by each turn to get the final field generated by the coil.

What's the point?   The point is that if you are working with coils, just a regular coil winding on a spool of some diameter and some length and some number of turns will be fine.  All exotic coil winding configurations ultimately are not that much different from you basic standard cylindrical coil that you can see anywhere.

Think of a pancake coil and do the same thought experiment were you look at it turn by turn.  If you have never done that thought experiment and do it now you will realize that there is a significant amount of flux self-cancellation going on in a pancake coil, much more than a standard coil.  The larger outer windings will work against windings in the middle of the coil in the "air gap" betwween the two windings.

My favourite "bad boy" coil is a Rodin coil.  Ultimately, there is not a single thing that a Rodin coil can do that a regular coil cannot do better.  A regular coil will always be able to do what a Rodin coil can do with less wire, so a regular coil is more efficient from a materials point of view.  Think about how much self-cancellation there is going on in a Rodin "starship" coil.  The points of the star are useless and do nothing for the coil.  When you think of it, the adjacent star points are engaging in flux cancellation with their neighbouring star points.  So at least that aspect will reduce the inductance of the "Rodin starship" coil.

Perhaps the funky coil windings in a Rodin coil give it more self capacitance and for some unusual reason you want that.  BFD, just put a super tiny capacitor in parallel with a regular coil.

Anyway, that's for you guys and girls to contemplate.  Coils are basic circuit building blocks or electromagnets.  There is no real reason to investigate all sorts of exotic winding techniques.  Likewise some people believe that a coil's windings have to be perfectly neat.  A messily wound coil and a neatly wound coil will be virtually identical.

Wow, that was a big posting!

MileHigh
« Last Edit: May 15, 2013, 01:40:00 PM by MileHigh »

Offline Farmhand

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #96 on: May 15, 2013, 11:32:30 AM »
Nice post MileHigh, and to add, neatly wound coils look nice and take up less space but they get hotter easier and take longer to cool because of a lack of airflow through the windings. Wrapping the outside of the coils with tape also allows heat to build up, I don't think a bit of warm is bad for coils unless they get actually too hot or radiate unwanted heat to other things, sealing up a coil (like with tape) can show better if it is dissipating energy through heat, by making it more noticeable. Bottom line with neat coils is they take up a lot less space when trying to fit stuff in a box.

What about aluminium wire, why can't we use insulated aluminium wire to make coils ? It's a lot less weight. What is the lightest core material with the best qualities ?

What do we need to make the lightest high energy electromagnet/motor coils we can make, like for applications in bicycles and such things ?

Cheers

Free Energy | searching for free energy and discussing free energy

Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #96 on: May 15, 2013, 11:32:30 AM »
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Offline Magluvin

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #97 on: May 16, 2013, 01:52:05 AM »
I am assuming a lot of you know the Hyperphysics web site.  It's a great resource.

http://hyperphysics.phy-astr.gsu.edu/hbase/hph.html
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/indcur.html#c2
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/indsol.html#c1

Here is something to ponder:  When you look at a coil, you can separate it into individual loops of wire.  Each loop will generate a magnetic field that looks like the familiar toroid that extends out to infinity.  So you simply add the magnetic fields together from each loop to get the true magnetic field generated by the coil.  The only tricky thing to remember is that the magnetic field is represented by a vector that has both magnitude and direction.  Therefore all of the additions are vector additions.

And when you strip it down to it's bare-bones reality, that's all there is.

If there is a core inside the coil, then each loop will tend to have more of the magnetic flux it generates travel through the core.  If the windings are many layers thick, the outer windings see a core that is further away with some "air" in between.  Since the "air" is much less conducive to the passing of magnetic flux than the core, almost all of the magnetic flux generated by the outer loops will also travel through the core.   So there is very little difference between a loop that's wrapped directly around the core material and an outer loop that's effectively 1/2 inch away from the core.  Both loops will contribute a nearly equal amount of magnetic flux through the core.  Naturally the outer loop will contribute a bit less because a very small amount of flux will flow through the "air gap."

You can use the terminology "lossy" for the outer loops in the sense that a very small amount of the flux they generate does not flow through the core.  So that's arguably "lost" flux.

What that means is many "exotic" coil winding schemes are exercises in futility.  I know I am using somewhat strong terms but it's true.  All the circuit cares about with respect to a coil is its inductance.  You can wind a coil in many fancy ways.  ZeroFossilFuel made "hemisphere" coils.  No doubt the magnetic field pattern generated by the hemisphere coils will be a bit different.  You can visualize it in your head, each loop creates the toroidal magnetic field pattern.  Some are larger than others and they are also offset from each other.  Big deal, you add up all of the magnetic field vectors and you are still left with an inductor, or an electromagnet.  If you plug the coil into an electrical circuit, the shape and the winding pattern of the coil means essentially nothing.  All that the circuit sees is that the coil has an inductance.  We are going to assume that the capacitance of the coil is minuscule and irrelevant and does not affect the operation of the circuit.

Now, think of some exotic coil winding configuration being used as a drive coil in a pulse motor.  Same deal, all the pulse motor cares about is that the coil has a certain inductance and generates a magnetic field.  Think of all the pulse motor clips with exotic drive coil winding schemes and break them down in your mind into individual turns, and add the magnetic field generated by each turn to get the final field generated by the coil.

What's the point?   The point is that if you are working with coils, just a regular coil winding on a spool of some diameter and some length and some number of turns will be fine.  All exotic coil winding configurations ultimately are not that much different from you basic standard cylindrical coil that you can see anywhere.

Think of a pancake coil and do the same thought experiment were you look at it turn by turn.  If you have never done that thought experiment and do it now you will realize that there is a significant amount of flux self-cancellation going on in a pancake coil, much more than a standard coil.  The larger outer windings will work against windings in the middle of the coil in the "air gap" betwween the two windings.

My favourite "bad boy" coil is a Rodin coil.  Ultimately, there is not a single thing that a Rodin coil can do that a regular coil cannot do better.  A regular coil will always be able to do what a Rodin coil can do with less wire, so a regular coil is more efficient from a materials point of view.  Think about how much self-cancellation there is going on in a Rodin "starship" coil.  The points of the star are useless and do nothing for the coil.  When you think of it, the adjacent star points are engaging in flux cancellation with their neighbouring star points.  So at least that aspect will reduce the inductance of the "Rodin starship" coil.

Perhaps the funky coil windings in a Rodin coil give it more self capacitance and for some unusual reason you want that.  BFD, just put a super tiny capacitor in parallel with a regular coil.

Anyway, that's for you guys and girls to contemplate.  Coils are basic circuit building blocks or electromagnets.  There is no real reason to investigate all sorts of exotic winding techniques.  Likewise some people believe that a coil's windings have to be perfectly neat.  A messily wound coil and a neatly wound coil will be virtually identical.

Wow, that was a big posting!

MileHigh

"What that means is many "exotic" coil winding schemes are exercises in futility."

Wow. You really dont want us to mess with these coils do you.? ;D Im not going to fight here, but I will respond as I see fit.

The first thing Im seeing with the bifilar is it takes on a charge much faster than a normal coil. With a coil that has more turns, the resistance is higher, sure, and the inductance is higher also. But it doesnt seem to act like a large inductor does with with an uphill climb in current due to high impedance. So it seems that the difference is that the bifi takes in current quicker and produces the magnetic field to its max much quicker, possibly instantaneously as compared to a normal coil of the same dimensions. This is far from just adding a cap across a coil. Will do some vids as I get things set up to see things more clearly.


"All the circuit cares about with respect to a coil is its inductance"

Thats not true. If there is capacitance in the coil, it should be ignored, right? If we were to put a cap across a normal coil as you say, if we pulsed it like in a pulse motor, the very first thing the circuit sees is the capacitance and the circuit charges it before much happens in the coil. But in the bifi, the charging of the capacitance happens through the windings of the coil, and since the capacitance neutralizes the self inductance till the capacitance of the coil is fully charged. Talking a DC pulse of course.


"If you plug the coil into an electrical circuit, the shape and the winding pattern of the coil means essentially nothing."

If we wound a random ball of wire, and a nice neat coil of the same wire and length, there are many differences between them. ;)


"We are going to assume that the capacitance of the coil is minuscule and irrelevant and does not affect the operation of the circuit."

Why exactly should 'we' 'assume' this? What if we didnt? ;)


"Think of a pancake coil and do the same thought experiment were you look at it turn by turn.  If you have never done that thought experiment and do it now you will realize that there is a significant amount of flux self-cancellation going on in a pancake coil, much more than a standard coil.  The larger outer windings will work against windings in the middle of the coil in the "air gap" betwween the two windings."

Personally I dont think the pancake is a good choice for a pulse motor driver or pickup coil. If the magnetic field of the magnet cuts only a mall portion of the coil at a time, like passing only a section of windings as it passes, the inductance of the rest of the coill works against current flow. Its better to have the windings bundled up so that the field 'cuts' all and as much of the windings on one side of the coil as possible. Even better to have an opposite magnet field cutting the other half of the coil at the same time to avoid the inductance hindering currents to flow quickly. Look at the windings of an alternator and look at the gaps in the core where the magnetic field is 'dragged' through in order to 'cut' the windings to induce current flow. They are not wound on spools wound in a circle. They are wound lengthwise and the portions of the windings that are not in a position for the magnetic fields of the rotor(with field core inside) to 'cut' them, are very short and bend around to the next core gap. So most of the coil in the alternator, both sides at the same time are being induced by the rotor with little left virtually untouched by the rotors passing field where the windings bend and turn into the next core gap.

These cores are what many motor builders should concentrate on in order to make the best use of controlling how the fields cut the windings as a gen coil and controlling and condensing the drive fields also. I Have a reply for Farmhand to one of his posts today in the confirming delayed lenz thread, where ill show the inside of my bike motor and another little treasure that I found from spare parts at work from a VW Touareg that I will be working with soon. ;D

When we make pulse motors with 1 drive coil, if we dont capture and direct as much of the field of the coil to the rotor, then we are wasting energy. If we have 1 coil and not using the back end of the coil we are wasting a lot. That 1 coil can be configured to apply both ends of the coil to the rotor using core materials and the rotor will essentially act like 2 coils were used instead of 1. ;) Doing this will give more rotor torque and speed using the same single coil.


"There is no real reason to investigate all sorts of exotic winding techniques."

Welp, Im gunna do it anyhoo.  ;D



"Likewise some people believe that a coil's windings have to be perfectly neat.  A messily wound coil and a neatly wound coil will be virtually identical."

Can you provide a good link that describes what you are saying in the above quote? ;)
Thane uses messy wound coils from what I hear. ;)


Mags

Offline MileHigh

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #98 on: May 16, 2013, 03:17:39 AM »
Magluvin:

Good luck in your investigations and I will make a few comments.

Quote
The first thing Im seeing with the bifilar is it takes on a charge much faster than a normal coil. With a coil that has more turns, the resistance is higher, sure, and the inductance is higher also. But it doesnt seem to act like a large inductor does with with an uphill climb in current due to high impedance. So it seems that the difference is that the bifi takes in current quicker and produces the magnetic field to its max much quicker, possibly instantaneously as compared to a normal coil of the same dimensions. This is far from just adding a cap across a coil. Will do some vids as I get things set up to see things more clearly.

When you say "charge" I am assuming that you mean current flowing through the coil to energize it.  If we assume that a series bifilar coil gets the inter-coil capacitance charged right away (which would have to be verified), and we are really simplifying things here, it's still impossible to escape the fact that it takes electrical work to energize the coil and build up the magnetic field.  There seems to be a train of thought that somehow a series bifilar coil allows the coil to energize very quickly, seemingly implying that this can be done at very little energy cost.  It's simply impossible, to build up a magnetic field takes electrical work.  That work ends up being stored in the magnetic field.  The stored energy is 1/2 L i-squared.  Note for a flywheel it's 1/2 MoI omega-squared - the same formula.

There is just no "jailbreak" for energizing a coil, be it a regular coil or a series bifilar coil, which as we know is just a different winding pattern for a regular coil.  Beyond that, I am not aware of any serious analysis of this on YouTube or elsewhere.  I don't want to be a party pooper, but to the best of my knowledge this issue simply never comes up in the real world.

The true actual dynamics of how a series biflar coil actually will actually react is not trivial at all and is probably beyond the capabilities of most forum experimenters.  It's possible that your testing will show something, and it's just as easily possible that the effects will be so small that it will be hard to discern what is causing them.

For example, look at this Spice model and analysis of a transformer:
http://fmtt.com/Transformer%20SPICE%20Model%202-14-08.pdf

This image is called, "Fig. 1. Equivalent circuit of single-phase power transformer windings."
http://ars.els-cdn.com/content/image/1-s2.0-S037877961000060X-gr1.jpg

So if you are going to get "hardcore" the actual modelling of how series bifilar coil works and reacts to an outside stimulus could get incredibly complicated.

I suppose the question is is it worth the trouble?  Perhaps just an A-B comparison between two coils with the same number of turns, one regular, one series bifilar would be a good test.   Supposing you notice a tiny current inrush on the series bifilar when you energize it and you don't see that with regular coil.  Like I already said, there is no magic bypass for the energy it will take to energize either coil.

So this possible tiny current inrush, does it mean anything?  Can you do anything practical with it?   That's the real question.

The theme behind my posting is to try to recognize what's relevant and what's not relevant when you experiment.  That is an important basic fundamental skill worth learning.  Do you spend hours and hours doing some kind of special winding for a coil or do you spend 20 minutes and just wind an ordinary coil, or do you buy a spool of wire at the electronics store and have an "instant coil?"

MileHigh

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #98 on: May 16, 2013, 03:17:39 AM »
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Offline Magluvin

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #99 on: May 16, 2013, 03:32:19 AM »


What about aluminium wire, why can't we use insulated aluminium wire to make coils ? It's a lot less weight. What is the lightest core material with the best qualities ?

What do we need to make the lightest high energy electromagnet/motor coils we can make, like for applications in bicycles and such things ?

Cheers

Ugh!!! just tried to post the pics of my bike motor. And I lost a long post. The files were too much to post and when I went back to pull some pics and post them in another post it was all gone. Ugh!!!

heres the pics, will post the text in a bit. Spent an hour sizing and writing. Ugh ugh. ;D

Ok figured it out. Some pics were not resized.

Ill condense my post here.

The bike motor is asymmetrical where the coils fire off at different times for smooth torque and reduce cogging. I want to replace the bikes control board with an Arduino to reduce the restrictions programmed in. Different number of mags vs coils.
The last 2 pics are of the main parts of an alternator from a 2004 5L twin turbo Touareg. it has permanent magnets!!  Never seen that before. And I can configure it like the bike motor to be a motor. Its asymmetrical also but just a different number of elements. Ill use this to test and try the Arduino as a controller before I build for the bike.

Removing the core of the bike motor is a serious effort. Putting it back in I will have to make a jig. Were talking a lot of force here. Squash finger like grape. Mr Miagi said.  ;D

Also the alternator is a sweet setup to mess around with otherwise. Using motors that are already made and modding them will give the advantages of premade framework to control the flux efficiently within the motor. Making motors with 1 round coil that doesnt even take advantage of the back side of the coils fields and is extremely inefficient. Lots of waste of input. This goes for motors and gens. Its ok for comparison testing and gathering field collapse, but not much torque or gen activity from the motoring part. RC motors are great bases to work with. Larger motors are probably easier to rewind and less costly is many ways. The RC motors can get pretty expensive for such a small package. Some are reasonable.

Had a lot more in the lost post but I gota git. ;D

Mags

Offline MileHigh

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #100 on: May 16, 2013, 03:46:28 AM »
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Thats not true. If there is capacitance in the coil, it should be ignored, right? If we were to put a cap across a normal coil as you say, if we pulsed it like in a pulse motor, the very first thing the circuit sees is the capacitance and the circuit charges it before much happens in the coil. But in the bifi, the charging of the capacitance happens through the windings of the coil, and since the capacitance neutralizes the self inductance till the capacitance of the coil is fully charged. Talking a DC pulse of course.

Ignoring the capacitance of the coil or not ignoring the capacitance of the coil depends on what you are doing.  If you are using the coil as a drive coil for a pulse motor or as a pick-up coil for a spinning rotor then yes, you can ignore the capacitance.  Remember I crunched Farmhand's measurements on one of his coils and noted that the capacitive energy in the coil was 1/17,000th of the inductive energy in the coil under typical conditions?

If you are talking about a small coil that's on a PCB that's part of a very high frequency analog circuit design, then you probably have to consider the capacitance of the coil.  Nobody on the forums is doing very high frequency analog circuit design.

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the capacitance happens through the windings of the coil, and since the capacitance neutralizes the self inductance till the capacitance of the coil is fully charged.

What do you and Farmhand and possibly others really mean when you say "neutralizes" in this context?

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Why exactly should 'we' 'assume' this? What if we didnt?

It goes back to the theme of my posting.  You want to try to direct your energies and your time to where it counts.  You mechanic says to you that you should check/change your oil every 3000 miles.  Most people might only change it every 6000 miles and not check it at all and just change their oil three or four times a year.  So do you stop your car every 100 miles and get out, check the old level and smell it and contemplate changing it?  Is that good use of your time?

In a way you can say that there are kind of "electronic fetishes" that run rampant in the free energy forums and they waste a lot of people's time.  Worrying about the minuscule transient capacitance in a pulse motor drive coil would be one of them.  Some people have battery fetishes where they believe their circuit has to be connected to a battery to work properly and a regular bench power supply will "kill the effect."  Several years ago people played with car ignition coils and they noticed that their CFL lights light up brighter when they made a connection to earth ground.  So there was a crazy belief that "power comes up from the ground."  That one is still running rampant.

MileHigh

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #100 on: May 16, 2013, 03:46:28 AM »
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Offline Magluvin

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #101 on: May 16, 2013, 04:17:45 AM »
Magluvin:

Good luck in your investigations and I will make a few comments.

When you say "charge" I am assuming that you mean current flowing through the coil to energize it.  If we assume that a series bifilar coil gets the inter-coil capacitance charged right away (which would have to be verified), and we are really simplifying things here, it's still impossible to escape the fact that it takes electrical work to energize the coil and build up the magnetic field.  There seems to be a train of thought that somehow a series bifilar coil allows the coil to energize very quickly, seemingly implying that this can be done at very little energy cost.  It's simply impossible, to build up a magnetic field takes electrical work.  That work ends up being stored in the magnetic field.  The stored energy is 1/2 L i-squared.  Note for a flywheel it's 1/2 MoI omega-squared - the same formula.

There is just no "jailbreak" for energizing a coil, be it a regular coil or a series bifilar coil, which as we know is just a different winding pattern for a regular coil.  Beyond that, I am not aware of any serious analysis of this on YouTube or elsewhere.  I don't want to be a party pooper, but to the best of my knowledge this issue simply never comes up in the real world.

The true actual dynamics of how a series biflar coil actually will actually react is not trivial at all and is probably beyond the capabilities of most forum experimenters.  It's possible that your testing will show something, and it's just as easily possible that the effects will be so small that it will be hard to discern what is causing them.

For example, look at this Spice model and analysis of a transformer:
http://fmtt.com/Transformer%20SPICE%20Model%202-14-08.pdf

This image is called, "Fig. 1. Equivalent circuit of single-phase power transformer windings."
http://ars.els-cdn.com/content/image/1-s2.0-S037877961000060X-gr1.jpg

So if you are going to get "hardcore" the actual modelling of how series bifilar coil works and reacts to an outside stimulus could get incredibly complicated.

I suppose the question is is it worth the trouble?  Perhaps just an A-B comparison between two coils with the same number of turns, one regular, one series bifilar would be a good test.   Supposing you notice a tiny current inrush on the series bifilar when you energize it and you don't see that with regular coil.  Like I already said, there is no magic bypass for the energy it will take to energize either coil.

So this possible tiny current inrush, does it mean anything?  Can you do anything practical with it?   That's the real question.

The theme behind my posting is to try to recognize what's relevant and what's not relevant when you experiment.  That is an important basic fundamental skill worth learning.  Do you spend hours and hours doing some kind of special winding for a coil or do you spend 20 minutes and just wind an ordinary coil, or do you buy a spool of wire at the electronics store and have an "instant coil?"

MileHigh

"it's still impossible to escape the fact that it takes electrical work to energize the coil and build up the magnetic field."

I realize that. Never said that less energy would be used with a bifi. Just saying it seems to get to peak much faster than a normal coil. Looking into it  still.


"There seems to be a train of thought that somehow a series bifilar coil allows the coil to energize very quickly, seemingly implying that this can be done at very little energy cost."

I dont see how energizing the coil more quickly 'implies' that there is less energy cost. But that quick to energize is not the norm for a big coil.


"There is just no "jailbreak" for energizing a coil, be it a regular coil or a series bifilar coil, which as we know is just a different winding pattern for a regular coil.  Beyond that, I am not aware of any serious analysis of this on YouTube or elsewhere.  I don't want to be a party pooper, but to the best of my knowledge this issue simply never comes up in the real world."

Well we dont know this for sure yet. And yes there isnt much serious definitions of functionality of bifi out there that match what Tesla says about it. 
"but to the best of my knowledge this issue simply never comes up in the real world"
Well there may be more than one reason for that, not just that it is useless or a waste of time. Using them in a simple pulse motor may not show all its colors. This is why Im choosing to use the Arduino to accurately time the pulses to see if the coil really produces a stronger field quicker than a normal coil.


"So if you are going to get "hardcore" the actual modelling of how series bifilar coil works and reacts to an outside stimulus could get incredibly complicated."

No more than a normal coil, right?  ;)


"I suppose the question is is it worth the trouble?  Perhaps just an A-B comparison between two coils with the same number of turns, one regular, one series bifilar would be a good test."

Yes, and yes. Ive made another plexi bobbin for a normal coil also. Like I said earlier, to get the most difference we have to have more turns. The normal coil looses its capacity with more turns, but the bifi increases it. 

A single turn coil will only have any close proximity capacitance where the ends of the coil meet. A tiny area. A 2 turn regular coil will have the 50% difference between the 2 turns measured next to each other like a bifi, but this difference decreases with every additional turn. The bifi does not.



"Do you spend hours and hours doing some kind of special winding for a coil or do you spend 20 minutes and just wind an ordinary coil, or do you buy a spool of wire at the electronics store and have an "instant coil?" "

I mostly wind my own coils. Some are old passive crossover coils. Bifi using just a role of speaker wire, the insulation would reduce the capacitance(the actual capacitance) between windings. Been looking at different litz that use larger rectangular insulated conductors woven very neatly with very little air space between each other. Then at the ends separate them into 2 bundles to create 2 separate woven windings in 1.

Mags

Offline Magluvin

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #102 on: May 16, 2013, 04:32:10 AM »
I Have a reply for Farmhand to one of his posts today in the confirming delayed lenz thread, where ill show the inside of my bike motor and another little treasure that I found from spare parts at work from a VW Touareg that I will be working with soon. ;D



Forgot to mention that I realized it was this thread that Farmhand posted. Got lost with my original second post. ;D Pics above.

Mags

Offline TinselKoala

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #103 on: May 16, 2013, 12:16:14 PM »
Kenneth Corum and James Corum.

There is a lot of misunderstanding and even disinformation about Tesla, Tesla coils, and the Tesla bifilar winding patent, and series bf vs. parallel bf vs. ordinary winding, etc. The Corums get it right, but their work is highly technical and hard to find in "condensed" form.

Tesla wanted low resonant frequencies with as little wire as possible and without the expense and difficulty of large and expensive and dangerous HV capacitors. A precisely constructed and tuned, flat pancake "series bifilar" coil's greatly increased self-capacitance allowed him to achieve that goal. His purpose was to attain very fast (for those days) rise and fall times in the primary coils of his power systems. The faster the transitions in the primary, the greater the voltage induced in the secondary. This is why, for example, modern square-wave SSTC drivers are able to pump up such high secondary voltages without HV in the primary or spark gaps: the fast rise and fall times of the pulses is accomplished by the modern semiconductors and the driver circuitry.
The "ideal" Tesla coil/power transmission system might consist of a low-frequency secondary, driven by a Tesla bifilar primary, using no tank capacitor but only the coil's self-capacitance, to attain a low resonant frequency of its own, matched to the secondary. Such a coil would have to be physically large and very precisely constructed, and it's doubtful that even modern semis, like large IGBTs, would be able to handle the stress of driving it at high power levels.

There are winding schemes that have "special" effects on coils. I think these do things like change the ratio of DC resistance to the inductance attained in the coil. Take a look at some old radio RF coils or chokes. You will see all kinds of mysterious winding patterns. Even my simple loopsticks have a dual coil, separated by a specific gap, and each coil is wound in a herringbone crossover pattern, very neatly, with cotton-covered, enamelled Litz wire. You can be sure that the makers would not have bothered to do this if a simple single, random-wound coil of the same amount of wire would 'do the trick'.

Offline Farmhand

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #104 on: May 16, 2013, 03:32:47 PM »
Nice motor and alternator Mags, I'll have to have a close look at the pictures, thanks ! Not using one side of the magnetic field of a very low loss inductor will not waste much energy Mags, at most it will waste some space I think. If the inductor has zero Ohms DC resistance it would have almost no losses, the loss is in the heat from the resistance or how you use the coil.  ;)

MileHigh, Some of us do experiment with high frequency stuff, and when we tune a circuit to resonance every pF of capacitance matters quite a bit in some places. ie, a few pF is nothing to the 240v input or even the 2000v out from each MOT at 50 Hz but a few pF in the elevated toroid or sphere terminal is what we tune with or to. It cannot be ignored period. If we did ignore it we would never get our big coils tuned properly and throwing large sparks continuously or any light from fluro's in the hand with small coils ect. If a resonant coil is working at around 1 mHz or so and it only has 30 or 40 pF in it's entire resonating circuit then 2 pf makes a big difference, if there was no need for resonance it wouldn't make any difference. Maybe a lot of Tesla's stuff doesn't make much sense unless the resonance aspect is considered as part of the intended working principal of the circuit. Without worrying about resonance a few hundred pF means nothing yes, no doubt about it. But if we want resonance and the capacitance is small (and the frequency high) every pF matters.

Cheers

P.S. MileHigh, By "neutralizing the self inductance" we mean "neutralizing" the effect of the delay in the flow of current because of the self inductance, which is what Tesla wrote in the patent. At resonance we can have a lot more current flow more easily through a coil, my pulse motor is a prime example when the circuit is not at or near resonance frequency the inductance restricts the flow of current as in the usual way, but when at or near resonance current flows without much regard to the inductance because the current limiting effects are neutralized. We still get the magnetic power of the high inductance coil but the current can flow more than with no resonance, that's the point. Why wait so long for the current to flow through a coil if we don't need to or try to force it.

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