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Author Topic: Tesla's "COIL FOR ELECTRO-MAGNETS".  (Read 451683 times)

Offline conradelektro

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #660 on: January 16, 2014, 06:17:41 PM »
I want to reproduce the experiment which Itsu shows in his video http://www.youtube.com/watch?v=syxL4f2OsPg (resonance with magnet spinner, speed up under load).

Luckily I found an old "Bedini coil" in one of my boxes with stuff from past experiments. (See the attached photo.)

The coil is bifilar (one wire 0.2 mm the other 0.3 mm diameter magnet wire, in series) and has many turns. If I do a calculation with this calculator http://www.66pacific.com/calculators/coil_calc.aspx I get about 3200 turns (I have forgotten the number of turns).

The coil parameters (measured with a 4 turn exciter coil and my function generator plus scope as I have learned with the pan cake coils, impedance was measured with my LCR meter and calculated from "parallel LC circuit" resonance tests):

DC resistance about 97 OHm
length 52 mm
diameter 38 mm
core 10 mm (hole in core only 7 mm)

air core
measured impedance:  at 100 Hz    --> 168 mH
                                     at 1 KHz      --> 176 mH
                                     at 10 KHz    -->   46 mH
self resonance at 4600 Hz
self capacitance            with assumed 170 mH   --> 7 nF
                                     (with assumed   44 mH   --> 26 nF)
experimental impedance:          810 Hz resonance with 0.22 µF cap     --> 172 mH
                                               390 Hz resonance with 0.986 µF cap   --> 169 mH
                                               120 Hz resonance with 10.08 µF cap   --> 174 mH
steel bolt as core
measured impedance:  at 100 Hz         --> 520 mH
                                    at 1 KHz         --> 320 mH
                                    at 10 KHz       -->   44 mH
self resonance at 4000 Hz
self capacitance            with assumed  520 mH   --> 3 nF
                                   (with assumed   44 mH   --> 35 nF)
experimental impedance:          520 Hz resonance with 0.224 µF cap --> 418 mH
                                               225 Hz resonance with 0.986 µF cap   --> 507 mH
                                                 70 Hz resonance with 10.08 µF cap   --> 512 mH

And if you look at the resonance frequency of an LC circuit with this coil and a 10 µF capacitor, one sees that it would resonate at 120 Hz (air core) or 70 Hz (steel bolt core).

I can realise these speeds (7200 rpm and 4200 rpm) with my new "12 DC motor ring magnet spinner" to recreate the resonance condition Itsu is showing (LC circuit resonating at 70 Hz or 120 Hz: coil + 10 µF cap).

The new magnet spinner is almost finished with a professional coupling (and this coil is ready, also the 10 µF cap). But I will not have time till Monday to do any experiments.

In the meantime, what do the experts think? Can it be done like this, should I try this and what are the difficulties and pitfalls?

I do not have a matching monofilar coil. The "speed up under load test" would then only be with this big fat bifilar coil.

Greetings, Conrad

Offline synchro1

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #661 on: January 16, 2014, 06:32:02 PM »
@Conradelektro,

Now your experiments are regaining interest and relevency. Let me just point out that multiple output coils split the output along with the acceleration effect! This is the bane of the Thane Heins generator. Nevertheless, it's a mistake to hide from the effect and pretend it's meaningless! I believe you'll return to the "Synchro Coil" research with renewed insights. It would be very simple to slip a stack of coupled radial magnets into the coil core, in place of that metal bolt, after you're through licking your wounds sufficiently.

Offline MileHigh

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #662 on: January 16, 2014, 07:05:20 PM »
Conrad:

It looks like you have all of the pieces to set up some great tests.

You notice how the measured inductance drops down a lot at 10 KHz.  I am not sure why and I am a bit surprised, especially for the air core.  So you should avoid your testing at the 10 KHz self-resonant frequency and stick to lower frequencies.

Looking forward to seeing the new magnet spinner configuration.

Quote
I do not have a matching monofilar coil. The "speed up under load test" would then only be with this big fat bifilar coil.

The good news is that if you use just one of the wires in your coil (the thicker wire) you will have a comparable, but not identical coil.  The geometry will be the same, but the inductance will measure about 1/4 the series bifilar version.   So you can still observe how that monofilar coil responds to it's own resonant condition and it will be comparable with the bifilar with the understanding that the inductance and resonant frequency has changed.  You just have to dial up the correct angular frequency on your magnet spinner.

Have fun!

MileHigh

Offline conradelektro

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #663 on: January 16, 2014, 07:50:34 PM »
You notice how the measured inductance drops down a lot at 10 KHz.  I am not sure why and I am a bit surprised, especially for the air core.  So you should avoid your testing at the 10 KHz self-resonant frequency and stick to lower frequencies.

The good news is that if you use just one of the wires in your coil (the thicker wire) you will have a comparable, but not identical coil.  The geometry will be the same, but the inductance will measure about 1/4 the series bifilar version.   So you can still observe how that monofilar coil responds to it's own resonant condition and it will be comparable with the bifilar with the understanding that the inductance and resonant frequency has changed.  You just have to dial up the correct angular frequency on your magnet spinner.

@MileHigh:

I just measured the inductance of one wire of my big Bedini coil,

it is 42 mH (air core) and 132 mH (steel bolt core)
same for both wires.

Great, you predicted the 1/4 inductance.

Inductance of one wire also drops at higher frequencies:

air core: 43 mH at 1 KHz and 11 mH at 10 KHz

steel core: 80 mH at 1 KHz and 10 mH at 10 KHz.


This calculator at http://www.1728.org/resfreq.htm then computes a resonance frequency of 138 Hz with a 10 µF cap (steel bolt core). And I hope that I can also do 138 Hz (8280 rpm).

But I will not be able to do 248 Hz (14880 rpm) with one wire air core.


The possible tests I envision (10 µF in LC circuit):

70 Hz --- bifilar, steel bolt core

120 Hz --- bifilar, air core

138 Hz -- monofilar (half coil), steel bolt core

248 Hz -- monofilar (half coil), air core not possible


My new magnet spinner should do up to 150 Hz (about 10.000 rpm). The 12 V motor should do up to 12300 rpm at 18 Volt (even 14800 with little load), but I expect some vibrations, why I do not dare to hope for more than 10.000 rpm).

Self resonance is at 4600 Hz (bifilar air core) and 4000 Hz (bifilar steel bolt core). I did not yet measure self resonance for one wire (half coil).

I did impedance measurements at 10 KHz (one of the settings of my LCR-meter) several times and also the LC-circuit resonance tests with several capacitors showed that the impedance drops rapidly with frequencies higher than 1 KHz. But I will only need the very low frequencies (70 Hz to 132 Hz).

Is it correct that high impedance coils do strange things at high frequencies (specially beyond their self resonance frequency)? 10 KHz (where the LCR-meter shows low impedance) is twice the self resonance frequency, the coil should do funny things?

Greetings, Conrad

Offline synchro1

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #664 on: January 16, 2014, 07:59:34 PM »
@Conradelektro,

Quote from Conradelektro,

"I want to reproduce the experiment which Itsu shows".

Itsu is running multiple magnets on a high speed precision VCR bearing! Your bipolar rpm has to multiply by the number of Itsu's rotor magnets to equal the same frequency!

How come your so smart know it all OU educator "Milehigh" can't tell you that!

Try the bearingless tube spinner on a ball bearing, with your original relay sensor circuit, placed on a concave cosmetic mirror. Don't be afraid of shattering the tube magnet at 25k. There's no hazard at that slow a speed. We get upwards of 300k before we encounter those kinds of problems. You can always put a PVC coupling around the setup, like I do, for extra precaution! Pay close attention to this: DLE=(Delayed Lenz Effect)

Quote from JLN:

"In the case of the generators, the increase of the turn rate is produced by the DLE when the devices are loaded above a "critical minimum frequency". Below the critical minimum frequency the DLE coil will produce deceleration as per any conventional Lenz generator coil. Coil frequency dictates coil impedance which is a critical factor in producing generator DLE and on-load system acceleration".

I call JLN's "critical minimum frequency" the "Lenz acceleration threshold speed".

JLN is motoring his bipolar spinner at 500 hertz which translates as 30,000 rpm. for his "Lenz delay test". Don't be disappointed if you get merely a slowing down effect at 10,000 rpm with a diametric!

Study JLN's DLE-Test-18 before you proceed:

http://jnaudin.free.fr/dlenz/DLE19en.htm

Offline gyulasun

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #665 on: January 17, 2014, 12:31:49 AM »
Hi Conrad,

When I have some more time this weekend I may add some more comments, now I notice only the eddy current losses of the steel bolt, influencing even the measurements you do when using the LCR meter but the thing is that several experimenters when doing the so called delayed Lenz effect tests often use bolts as a core, so you can test it too, of course.
Nevertheless, I advise to have at hand a normal ferrite rod piece too (OD=6mm length=40mm) from RS components (link: http://at.rs-online.com/web/p/ferrit-stabkern/4674065/ )  with one such core eddy losses will be negligibly small even at 10 kHz or higher.
Your link to the multilayer-multiturn coil calculator is okay and I would like to refer to another one I have recently found a bit more flexible and precise, works also on-line but freely downloadable too and have some additional plug-in softwares to make it more versatile (I have no any business interest with its creator  :D ),  see here: http://coil32.narod.ru/calc/multi_layer-en.html  and download it here, the plug-ins are also here: http://coil32.narod.ru/download-en.html

Regarding the drop in inductance at the 10 kHz LCR meter's measuring frequency for the air core series bifilar, I think the high value self capacitance of this multiturn bifilar coil causes it, see below the explanation. You may have also noticed that the air core bifilar has a bit higher inductance at 1 kHz (176 mH) than at 100 Hz (168 mH), this is because the 1 kHz is closer to the 4.6 kHz self resonant frequency, here I assume this latter frequency is the first parallel resonant frequency of the series bifilar coil caused by the about 170 mH inductance and the self capacitance.

The interesting thing is that such bifilar coils (connected as series bifilar like it is now) do have multiple resonances as the frequency increases, what is more: parallel and series resonances should alternate each other as you sweep the frequency due to the distributed nature of the self capacitance and inductance.
Here is a good site (watchable only via the internet wayback machine since last December)  on some measurements where the series bifilar coil is made of a coaxial cable and in Figure 10 the magnitude of the impedance is shown in the function of the frequency (the high impedance peaks are the parallel and the low impedance valleys are the series resonance points:  https://web.archive.org/web/20130321175122/http://vk1od.net/antenna/coaxtrap/index.htm 

When you have some more time next week, you may wish to check your multiturn bifilar coil in a measuring circuit and experience (by sweeping through the frequencies) the impedance peaks or the valleys manifested by the changing voltage values across the series bifilar, driving it from your function generator. (A good measuring circuit is to be figured out for that.)

Of course a coaxial cable is a transmission line where the outer conductor encircles the inner conductor and these two are inherently guided in parallel with each other of course. When you make a bifilar coil, the two pieces of wires can also be considered as a (long) transmission line where they are guided next to each other in parallel too (though quite often these are twisted to increase the capacitance between them).
Now you or MileHigh can understand why the inductance for the air core series bifilar is so small at 10 kHz: at this frequency the impedance is surely near to a series resonant point (near to an impedance valley) but it is still inductive. At a series resonant frequency (especially at the first series frequency just after the first parallel one) the impedance is nearly the DC resistance of the two series coils (plus some dielectric losses of the enamel and bobbin or core losses when you use any ferromagnetic core etc).

Greetings,  Gyula

Offline Farmhand

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #666 on: January 17, 2014, 01:26:25 AM »
OK something that has been touched on before but another advantage as compared to tuning a coil with an external capacitor is that with an external capacitor the cpacitance is at the end of the coil leads or terminals and so any current going to the capacitor must flow through the coil and it's DC resistance. Not so with the bifilar coil, there would be little to nil tank current flowing through the DC resistance of the coil, seems like.
Which must improve efficiency surely. I set up an isolation transformer with the coils wound on different parts of the big core last night and tuned the output coil with a 14 uf capacitor for 50 Hz, when I ran the setup the voltage at the output coil was more than the input coil, almost double, same turn count (inductances trimmed). But the input required was more.
The way I see it it is the current in the output coil "tank" for want of a better word causing more losses, if there was no capacitor there but the coil was a bifilar and was "specifically wound as Tesla describes" but instead for 50 Hz "resonance" as I did with the 14 uF capacitor the losses would be much less. The losses are proportionate to the voltage applied and the current induced in the "tank" through the resistance. Distributed capacitance would negate all that tank current and loss I think.

So tuning with a external capacitor is not the same as using a Coil For Electro-Magnets made to order for the same purpose, in that way at least and it's a big thing as I see it.

This is something we can test with the high resistance coils like Mags is making.  ;)

So one for the trained or self educated guys, with the capacitance evenly distributed how much resistive loss is involved in a coil with it's own evenly distributed tank capacitor as compared to a comparative coil (same inductance) but tuned with an external capacitor ? Same or different ?

When I first added the cap I figured it would increase the input of course as the activity is increased, but then I thought if that was a bifilar coil no cap would be needed across the coil and so no current would be flowing through the end of the coil with no load.


Quote
Capacity secured in this particular way possesses an additional advantage in that it is evenly distributed, a consideration of the greatest importance in many cases, and the results, both as to-efficiency and economy, are the more readily and easily obtained as the size of the coils, the potential difference, or frequency of the currents are increased.

..

P.S. On a side note it irks me to no end when people like Utkin when referring to this coil make statements like "No wonder Tesla always said this coil was an energy amplifying coil." I doubt he said that, I see no evidence of it.

In my opinion we should go through his claims and pick them to pieces. He just adds so much BS it make a joke out of Tesla's work. But people lap it up and re link it and promote the rubbish. I doubt very much Tesla ever uttered those words in relation to this coil or any other. But if he did ther ought to be record of it if people are saying he always used to say it. What a crock.

When I see Utkin or someone else make such a statement I immediately think, crackpot.

..


Offline Farmhand

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #667 on: January 17, 2014, 02:57:47 AM »
So to better explain what I'm envisioning, with a regular coil and tuning capacitor when the applied voltage declines and therefore the magnetic field declines to maintain the current, that current keeps flowing through the wire and it's resistance to the ends of the coils wire before it gets to the capacitor. But with the bifilar coil there is no capacitor at the ends of the coil. So what happens to the current ? My guess is the coils distributed capacitance takes current from along the entire length of the coils wire via the dielectric medium being the insulation on the wire. Just a guess that if so, the ESR of this capacitor is very good.

Any thoughts.     

P.S. As an example just say I had a coil of both kinds which has about 720 mH and about 22 Ohms DC resistance with 220 nF excited at 400 Hz.

A generator capable of 400 Hz and about 220 volts would be nice to experiment with. I wonder what the frequency of a car alternator would be at 1200 RPM, I'll have to check.
I could bypass the rectifier and use one phase of that maybe for a lower voltage. 

..

Offline Magluvin

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #668 on: January 17, 2014, 03:39:30 AM »
OK something that has been touched on before but another advantage as compared to tuning a coil with an external capacitor is that with an external capacitor the cpacitance is at the end of the coil leads or terminals and so any current going to the capacitor must flow through the coil and it's DC resistance. Not so with the bifilar coil, there would be little to nil tank current flowing through the DC resistance of the coil, seems like.
Which must improve efficiency surely. I set up an isolation transformer with the coils wound on different parts of the big core last night and tuned the output coil with a 14 uf capacitor for 50 Hz, when I ran the setup the voltage at the output coil was more than the input coil, almost double, same turn count (inductances trimmed). But the input required was more.
The way I see it it is the current in the output coil "tank" for want of a better word causing more losses, if there was no capacitor there but the coil was a bifilar and was "specifically wound as Tesla describes" but instead for 50 Hz "resonance" as I did with the 14 uF capacitor the losses would be much less. The losses are proportionate to the voltage applied and the current induced in the "tank" through the resistance. Distributed capacitance would negate all that tank current and loss I think.

So tuning with a external capacitor is not the same as using a Coil For Electro-Magnets made to order for the same purpose, in that way at least and it's a big thing as I see it.

This is something we can test with the high resistance coils like Mags is making.  ;)

So one for the trained or self educated guys, with the capacitance evenly distributed how much resistive loss is involved in a coil with it's own evenly distributed tank capacitor as compared to a comparative coil (same inductance) but tuned with an external capacitor ? Same or different ?

When I first added the cap I figured it would increase the input of course as the activity is increased, but then I thought if that was a bifilar coil no cap would be needed across the coil and so no current would be flowing through the end of the coil with no load.


..

P.S. On a side note it irks me to no end when people like Utkin when referring to this coil make statements like "No wonder Tesla always said this coil was an energy amplifying coil." I doubt he said that, I see no evidence of it.

In my opinion we should go through his claims and pick them to pieces. He just adds so much BS it make a joke out of Tesla's work. But people lap it up and re link it and promote the rubbish. I doubt very much Tesla ever uttered those words in relation to this coil or any other. But if he did ther ought to be record of it if people are saying he always used to say it. What a crock.

When I see Utkin or someone else make such a statement I immediately think, crackpot.

..

"So tuning with a external capacitor is not the same as using a Coil For Electro-Magnets made to order for the same purpose, in that way at least and it's a big thing as I see it."

Yep, I believe it is different. ;)   A normal coil with a cap in parallel, if we were to apply dc or say initial input, the cap is right there across the supply and takes on current immediately. So will the bifi coil. But the difference is, to charge the bifi cap, the charge has to go through the coil, but the typical LC this is not the case. They are not exactly the same. ;)

Ill have time to set up to wind that coil tomorrow evening.  The bobbins that Im using for twin spools to wind a single are going to need a free spinning place to reel off of. The wire is very thin and have learned to be careful. The bobbins are door panel clips with the lil christmas tree tips. No through hole. So I have some hobby bearings Ill temporarily mount on a base. The bobbins also have different amounts of wire depending on where they broke while winding them originally, so they have to be able to spin independently. But now I have good use for that wire. ;)

Im going to remove 3 coils(possibly more if need be) from the motor and use the one space in the middle for testing the 2 different coils so the motor coils dont interfere too much. They are all really close, bout 1mm spacing. The bifi will have a 4 pin terminal for trying different configurations.

Mags

Offline MileHigh

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #669 on: January 17, 2014, 03:55:49 AM »
Farmhand:

You are right about the current being lower for a self-resonating coil but your reasoning is incorrect.  The current is lower because the amount of energy stored in the self-resonating coil is lower, whether that be monofiler or series bifilar.

But firstly and formostly, you are forgetting the basics.  The current flow in the coil is synonymous with the energy stored in the coil, period.  You simply have to have current flow and deal with the associated i-squared-r losses no matter what.  There is no possible bypass or work-around for the current flow in a self-resonating coil, because the coil stores the energy in the current flow itself.

But here is a simple thought experiment:  If you have a regular capacitor in the LC circuit and start to decrease the value of the capacitor, the frequency goes up.  What is mentioned less often but is also true is that the AC voltage has to increase while the capacitor decreases in size.  If you read 10 volts AC when the cap is 100 uF, and you assume that the resonator energy remains constant, what is the AC voltage when the capacitance is only 37 pF?

The self-resonating coil with no capacitance would have to resonate at some crazy high voltage.  The voltage would be so high that the air would break down and the energy would be nearly instantly drained out of the coil.  And that's what happens all the time in real life.  If you connect a coil across a 1.5 volt battery, when you go to disconnect, the the coil discharges through a spark gap.  The spark gap may be so tiny that you don't hear it or see it but it is still there.

So, it's essentially impossible to have a self-resonating coil store a lot of energy because it "shorts itself out" the moment you go to disconnect from the battery.  Unless you are in a vacuum or do some experiments with coils submerged in insulating oil, a self-resonating coil in air will always be a low energy affair compared to the same coil connected to a capacitor.

MileHigh

Offline Farmhand

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #670 on: January 17, 2014, 04:47:52 AM »
In the theoretical case I refer to above the distributed capacitance of the bifilar coil is equal to the added capacitor capacitance and the distributed capacitance of the monofilar coil (in theory). So a bifilar coil with a distributed capacitance of 220 nF and a monofilar coil with whatever capacitance is needed added to it to get it to the same 220 nF. Probably need a lot of wire.

If someone wants to test it and that amount of distributed capacitance is not possible then the values could simply be changed to what is possible. Thing is both coils would have the same capacitance and inductance one has an external capacitor and one doesn't.

.

 On a side note it is surprising how many different configurations this transformer with the 16 windings on it can be configured. I can make four bifilar coils and connect them in different ways to get different measurements. Interesting...

..

Offline Magluvin

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #671 on: January 17, 2014, 05:43:16 AM »
In the theoretical case I refer to above the distributed capacitance of the bifilar coil is equal to the added capacitor capacitance and the distributed capacitance of the monofilar coil (in theory). So a bifilar coil with a distributed capacitance of 220 nF and a monofilar coil with whatever capacitance is needed added to it to get it to the same 220 nF. Probably need a lot of wire.

If someone wants to test it and that amount of distributed capacitance is not possible then the values could simply be changed to what is possible. Thing is both coils would have the same capacitance and inductance one has an external capacitor and one doesn't.

.

 On a side note it is surprising how many different configurations this transformer with the 16 windings on it can be configured. I can make four bifilar coils and connect them in different ways to get different measurements. Interesting...

..


For the sake of it, each wire loop in a bifi that is between the lead out first and last loops are little caps in series. lol it would be interesting to see if a bifi resonates at the regular coil freq because of it. Its got to be a bit different than where a normal coil, the plates of the cap are shunted somewhat by each turn, but the bifi are only shunted by half of the whole coil. Much easier for the bifi capacitance to have a high voltage. And maybe even if it can ring at normal coil freq also. ??? ;D


Weve got to try all kinds of ways to test. The amount of voltage difference working in these 2 different coil has to make a big difference in some way. I have some ideas that I want to try. Like dumping fields collapse current from another coil into the bifi capacitor. Where a normal coil would impede the spike, the bifi should take it in.  Might be a way of making good use of collapse spikes. Especially if those spikes are timed to res freq. ;D I also really want to try the multi core inductor experiments. Ive got some time starting tomorrow to fiddle.

Mags

Offline Magluvin

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #672 on: January 17, 2014, 06:12:57 AM »


 On a side note it is surprising how many different configurations this transformer with the 16 windings on it can be configured. I can make four bifilar coils and connect them in different ways to get different measurements. Interesting...

..

I have seen where there are 8 individual enameled wires twisted together as a single conductor used in switching supply windings. Take half(4) to make 1 winding and the other 4 for the other winding. Its like using 2 larger wires to make a bifi, but more capacitance. If we want more inductance and less resistance, use a core and less wire. So multistrand windings can help increase capacitance if we use less wire/turns by adding a core, and decrease resistance.

An alternative to multistrand to increase capacitance would be flat wire.

http://www.ebay.com/itm/REA-tinned-copper-flat-buss-wire-003-x-026-2-Lbs/261297961523?_trksid=p2050601.m2372&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D207%26meid%3D4172994119461631007%26pid%3D100085%26prg%3D1112%26rk%3D1%26rkt%3D4%26sd%3D261297961523%26%26clkid%3D4172999009395071920&_qi=RTM1562569

Just an example of many things out there.

Mags

Offline MileHigh

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #673 on: January 17, 2014, 06:30:58 AM »
Gyula:

Quote
The interesting thing is that such bifilar coils (connected as series bifilar like it is now) do have multiple resonances as the frequency increases, what is more: parallel and series resonances should alternate each other as you sweep the frequency due to the distributed nature of the self capacitance and inductance.

Thank you for that information, that's probably the most important posting around here in a while.  I suppose that could be simulated with some kind of lumped transmission line or something like that.  Your link looks like the real thing.  Ham radio guys are the real thing.

To add to that, when you pump some sort of signal into that complex filter, it's the way the individual frequency components in the signal react with the complex filter.   There are alternating poles and zeroes (peaks and nulls in the frequency response.)  The resultant response is addition of all the responses to the separate frequencies.  It's like a frequency "shake and bake" process that takes place.  I still think of a real physical spring in self-resonance.  There is a certain randomness and strangeness to the physical spring in self resonance because if you think about it there are actually two or more springs springs in one.  There is the spring that stretches along the axis, and the spring associated with the bending of the shaft of the spring.  The shaft can bend along two orthoganal axes, so that's like two springs.  The important point is that an ideal spring is massless, and the mass of the metal of the spring is modeled as a distributed capacitance.  It's a very good analogy for what we are talking about.

Also, I saw something once when I was a kid that was so cool.  It was a big disk that stood upright.  There was a big tuning dial on it.  You put it next to your AM radio and you could pull in far away stations and make them sound clear.  You moved the big dial to find the tuning spot.  Even as a kid I thought it must be some kind of tunable resonator, and now as an old kid I agree.  I should try looking it up online.  A passive LC resonator that resonates on the AM band.

MileHigh

Offline synchro1

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #674 on: January 17, 2014, 07:12:44 PM »

Here's a report of an experiment by contributor Neptune off the Muller Dynamo thread:

neptune
:

I did a small experiment today involving bifilar windings . Someone else posted a link to a website about this . I made 3 electromagnets using 3 similar iron cores . Each magnet used the same length of wire . One was wound normally , one bifilar and one quadfilar .The same power supply was used to test each electromagnet in turn . The strength of each was tested by seeing how many small nails it would lift . The results were as follows :

Normall wind - 4nails .
Bifilar wound - 12 nails .
Quadfilar - 12 nails .

Note that each electromagnet had the same core and the same Amp-turns. I was surprised that the quadfilar was no better than bifilar . This experiment seems ridiculous , but you MUST do it yourself . The implication is that by using a bifilar motor coil , you could create the same input torque for a much lower electrical input , maybe as low as one third . Got to be worth a try? But do the simple experiment first.

Here's a hyper-link to the page: It's at the bottom!

http://www.overunity.com/3842/muller-dynamo/3935/wap2/

Additional comment from Neptune:

mikestocks2006:

--- Quote from: neptune on July 01, 2011, 07:06:21 PM ---@ Nulpoints , and also in reply to Pm from Mikestocks 2006 ,  
Bifilar in my case is as follows . Take 2 wires , A and B . Wind them "2in hand2 side by side . do not twist the wires together , and try to avoid crossed turns . All 3 electromagnets are wound single layer . Connect the start of wire a to the power supply . Connect the END of wire A to the START of wire B. Connect the connect the END of wire B to the power supply . So current flows from start of A to the end of A which is then connected to the start of B . The source makes no mention of the shape factor of the coil , but shows a similar arrangement to above . The nails I used were three-quarter inch upholstery tacks (tin tacks).

Neptune is very clear about nature of the Tesla series bifilar connection he used in the test!