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Author Topic: Tesla's "COIL FOR ELECTRO-MAGNETS".  (Read 429157 times)

Offline gyulasun

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #675 on: January 17, 2014, 09:31:53 PM »
...

--- 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).
...


Hi Synchro1,

You omitted a very important sentence from the text Neptune posted above, the omitted sentence just followed the sentence I put in bold above,  and this is it also in bold (first the last sentence from above): "The nails I used were three-quarter inch upholstery tacks [tin tacks ].  Smaller nails would give a more accurate measurement,  my tests were quick and dirty."

So Neptune acknowledges that smaller nails (i.e. smaller than three-quarter inch long nails) would give more accurate results and that his tests were quick and dirty.  And don't you find it strange that he did not measure difference between the performance of the bifilar and the quadfilar electromagnets??  Or just the quick and dirty test is to blame in this latter case too?

If you recall, I asked you to use smaller iron pieces than your big paper clips you used in your video (I even asked you to chop them up to have much smaller pieces, remember?) to refine the measurements. This is why I repeated my own tests with small sized iron nuts and found no difference because earlier I did not find difference with my paper clips test either but I felt the paper clips were too big for the test.

And remember: Magluvin also did this test and he did not find any difference either. I agree with him that there is no difference between the DC performance of a series bifi electromagnet and a normal electromagnet when they have the same Amperturns, shape factor, same length of wire, same core properties etc.

Gyula

PS this is the link to Neptune's original post from which both synchro1 and I quoted:
http://www.overunity.com/3842/muller-dynamo/msg293547/#msg293547 


Offline synchro1

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #676 on: January 17, 2014, 10:06:47 PM »

@Gyulasum,

I just came across "Neptune's test report" while trying to research Itsu's rotor speed. Itsu says his parallel LC coil see's the rotor RPM at 150 hertz. What's the meaning of that? If the LC resonant coil lowers the "critical minimum frequency" for "Lenz acceleration" by 75%, that would really amount to something! It sounds to me like his rotor's doing more like 9,000. Can anyone tell me wether or not Itsu is spinning his rotor at 2,250 or 9,000 rpm in his resonant output coil video?

The other thing is, I actually managed to pick up a third trombone clip with my nail core bifilar electromagnet in my video at first, just like Neptune!

Offline tim123

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #677 on: January 17, 2014, 10:57:16 PM »
I repeated my own tests with small sized iron nuts...
Magluvin also did this test and he did not find any difference either....

If the two types of coil had the same measured inductance - but different strength magnetic fields - that really would be 'magic'... :)

Offline gyulasun

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #678 on: January 17, 2014, 11:28:15 PM »
...

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.


Hi MileHigh,

If you are interested, here are some comments on the "true equivalent circuit" (comments to a certain author, Mr Mueller's earlier article on coax traps):

https://web.archive.org/web/20130321175059/http://vk1od.net/antenna/coaxtrap/QexKom.htm 

Very briefly: it turns out that Mueller paper ( http://ebookbrowsee.net/gdoc.php?id=281896620&url=0fde726e1bf7bf65a20ee3d7db51914f&c=26010868 ) gave an 'equivalent' circuit for coaxial traps, which gave the first parallel resonance frequency but did not give any further higher frequency series or parallel resonances, and some works from other authors included some mistakes too, this paper has them listed: http://n6mw.ehpes.com/CT5.pdf 

Regarding your recalling "A passive LC resonator that resonates on the AM band", it indeed has been a useful device, and still is used by some AM radio fans pulling in distant AM broadcast stations. Recently I saw a youtube video on such an antenna version using several ferrite cores inside a big solenoid coil, see this for instance: http://www.youtube.com/watch?v=iqYZcRXCGxM 
Of course there have been many shapes and frames, I guess what you saw as a kid may have had a spider coil like shown here: http://makearadio.com/coils/spider.php (with a variable capacitor of course).

I mention this because an interesting "spin off" is also shown here: http://makearadio.com/coils/contracoils.php called as contra wound coils and although they are not 'classical' bifilar windings, they still manifest the 4 times inductance increase (due to the mutual inductance) when the two coils are connected in series, versus the the inductance value when the same two coils are connected in parallel.

Thanks,
Gyula

Offline gyulasun

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #679 on: January 17, 2014, 11:36:13 PM »
If the two types of coil had the same measured inductance - but different strength magnetic fields - that really would be 'magic'... :)

Hi Tim,

Yes they had the measured inductance within a few percent.
Here are the two tests, you may not have seen them, one with paper clips and the other with small nuts:
http://www.overunity.com/11350/confirming-the-delayed-lenz-effect/msg357838/topicseen/#msg357838
http://www.overunity.com/11350/confirming-the-delayed-lenz-effect/msg357952/#msg357952

Gyula

Offline synchro1

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #680 on: January 18, 2014, 12:05:44 AM »
If the two types of coil had the same measured inductance - but different strength magnetic fields - that really would be 'magic'... :)


The magnetic strength is not a magnetic field feature of the coil per se, but the way in which the coils magnetize the ferrite cores. The major difference in the core materials is super critical and definitely accounts for the huge difference in results.  

Seriously now; Take a close look at the coil cores in the pictures below: One's a soft iron on top, 16 penny nails called for by the test controller; The other Mag's used below are some kind of nickel or zinc coated alloy! Not to mention the threads! How could it be even remotely possible to get similar results with such two entirely different core materials? Give me a break, would you please? This comparison is ludicrous!

Offline gyulasun

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #681 on: January 18, 2014, 12:25:25 AM »
...
Can anyone tell me wether or not Itsu is spinning his rotor at 2,250 or 9,000 rpm in his resonant output coil video?
...

Synchro1:

In his parallel resonance video, Itsu mentioned his gen coil has 27mH inductance and the tuning capacitor was 40uF, giving 150Hz resonance by the calculation. When he run the motor with the capacitor connected, the scope measured about 146Hz, now if you multiply this by 60, you get 8,760 RPM. If it had measured 150Hz ouput frequency from the generator coil still tuned by the 40uF, then the RPM would have been 9,000 indeed.
And when he disconnected the 40uF capacitor, the rotor speeded up to a higher rpm, surely above 9,000 rpm.


Quote

The magnetic strength is not a magnetic field feature of the coil per se, but the way in which the coils magnetize the ferrite cores. The difference in the core materials appears to be critical and probably accounts for the difference in results. 


In those tests I referred to the cores were iron bolts or nails, no ferrite cores were used at all. 

How do you know that the 16 penny nails are made of soft iron? and the bolts are made of  a totally different iron? You measured them?

Offline synchro1

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #682 on: January 18, 2014, 12:31:51 AM »
Synchro1:

In his parallel resonance video, Itsu mentioned his gen coil has 27mH inductance and the tuning capacitor was 40uF, giving 150Hz resonance by the calculation. When he run the motor with the capacitor connected, the scope measured about 146Hz, now if you multiply this by 60, you get 8,760 RPM. If it had measured 150Hz ouput frequency from the generator coil still tuned by the 40uF, then the RPM would have been 9,000 indeed.
And when he disconnected the 40uF capacitor, the rotor speeded up to a higher rpm, surely above 9,000 rpm.


In those tests I referred to the cores were iron bolts or nails, no ferrite cores were used at all.  However, I agree with your last sentence, there can be and in fact there are significant differences in the magnetic properties of ferromagnetic materials, even between two iron bolts or nails that seem totally identical by the visual inspection. This is why we have to compare apples with apples.

Gyula


Thanks, that confirms my suspicion that Conradelektro's rotor needs to go faster to test his LC resonant coil.


I can tell from looking at the bolts that they are coated with a shiny metal, not soft iron!

Offline gyulasun

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #683 on: January 18, 2014, 12:37:48 AM »

Thanks, that confirms my suspicion that Conradelektro's rotor needs to go faster to test his LC resonant coil.


I can tell from looking at the bolts that they are coated with a shiny metal, not soft iron!

Synchro1,  that confirms nothing,  what are trying to connect here with what?

Offline synchro1

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #684 on: January 18, 2014, 12:50:42 AM »
@Gyulasun,

My point here is simply that a  N-S four magnet rotor spinning at 9,000 RPM is equal in frequency to a diametric magnet spinning at 18,000 RPM. Conradelektro plans to start spinning his diametric magnet at between 7,800 RPM and 10,000 RPM. Too slow to cut it!



         

Offline tim123

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #685 on: January 18, 2014, 10:57:12 AM »
It was an idle comment, but perhaps this is how to define & test the 'magic' that Conrad was questioning...

If the 2 coils have the same inductance, but different field strengths, then that surely would be magical? I certainly would be surprised...

We seem to have a difference in opinion - i.e. that Gyula recommends a small core, whereas Synchro (I think) is recommending a big core...?

I've just bought a couple of large-ish ferrite rods: 6" long x 1/2". Perhaps, when they arrive, I'll do the test too...

Offline Farmhand

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #686 on: January 18, 2014, 11:47:57 AM »
Well I could do the test with my own small coils , but I see no real point, the coils both have the same DC resistance and both have the same inductance and cores (iron powder rods), both coils will see the same current and create the same magnetic field. I'm reluctant to waste another night dong what others have already shown that I agree with.

Which is that when a continuous DC current is sustained through the two different coils they will behave the same, should be as exactly the same as is possible considering build tolerances.

I'm interested to see if there are any efficiency differences between some higher inductance, fairly high resistance (relatively)  coils of both monofilar and bifilar coils when excited with a frequency and loaded in various ways to various levels. One way to load a spiral AC electromagnet would be with a steel plate. A way to load a regular solenoid electromagnet might be to use it as a mechanical oscillator drive or something.

Of course my use of the general  term "resonance" is wrong when talking of simply tuning a systems L or C to get maximum power through a load on a "tank".

Tesla did not use the term resonance in the patent and I can accept I used the wrong term, if resonance played a major part he would have said so in the patent as he was not afraid to use the term. I will change my language in future to say simply tune the circuit.

Cheers

 

Offline gyulasun

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #687 on: January 18, 2014, 02:12:52 PM »
@Gyulasun,

My point here is simply that a  N-S four magnet rotor spinning at 9,000 RPM is equal in frequency to a diametric magnet spinning at 18,000 RPM. Conradelektro plans to start spinning his diametric magnet at between 7,800 RPM and 10,000 RPM. Too slow to cut it!

         

Synchro1, 

You may have demonstrated already but I missed it:  how did you measure the diametric magnet's spinning at 18,000 rpm?  Or if you did not measure it, how did this rpm come about? 

Have you measured any output power created by this magnet spinning at this rpm?  Please share measurement facts because you have not mentioned any meaningful measured data so far. 
I am not asking you to give out your 'magic' or 'secret',  just state your measurements,  for I suppose you have done some real measurements not to delude yourself for months or years? 
Once you wrote that the input current got decreased when the 'magic' happened (i.e. you may have reached the rpm needed for the 'magic'),  then what the reduced current draw was at 12V and what was the output power then? how did you check it? 

Gyula

Offline gyulasun

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #688 on: January 18, 2014, 02:31:29 PM »
Hi Tim,

I did not mean to recommend any core size, small or big,  if any "magic" is supposed to happen,  then the person stating the magic should define the sizes.

Hi Farmhand,

Tesla wrote in the Coil for Electromagnet patent:

"The effects of self-induction, above referred to, are known to be neutralized by proportioning to a proper degree the capacity of the circuit with relation to the self-induction and frequency of the currents." ... "This is due to the mutual relations existing between the special character of the current and the self-induction and capacity of the coil, the latter quantity being just capable of neutralizing the self-induction for that frequency."
   
So he did not use the word resonance but I am a 100% sure that he meant making the capacitive reactance of the self capacitance of his coil to be equal to the inductive reactance of his coil because I think this is the only way  "that permits a current of given frequency and potential to pass through it (i.e. the coil) with no other opposition than that of ohmic resistance, or, in other words, as though it possessed no self-induction."

And when you make a coil's reactance to be equal to a capacitor's reactance and  or vice versa,  and this capacitor is either in parallel or in series with that coil,  then you have a resonant LC circuit simply because it is the condition for resonance as we know.
So Tesla had to have a resonant condition in order to achieve his claims in the patent, even though he did not use the word resonance in the text.

Gyula

Offline synchro1

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Re: Tesla's "COIL FOR ELECTRO-MAGNETS".
« Reply #689 on: January 18, 2014, 03:49:51 PM »
Synchro1,  

You may have demonstrated already but I missed it:  how did you measure the diametric magnet's spinning at 18,000 rpm?  Or if you did not measure it, how did this rpm come about?  

Have you measured any output power created by this magnet spinning at this rpm?  Please share measurement facts because you have not mentioned any meaningful measured data so far.  
I am not asking you to give out your 'magic' or 'secret',  just state your measurements,  for I suppose you have done some real measurements not to delude yourself for months or years?  
Once you wrote that the input current got decreased when the 'magic' happened (i.e. you may have reached the rpm needed for the 'magic'),  then what the reduced current draw was at 12V and what was the output power then? how did you check it?  

Gyula


I place the critical minimum frequency for DLE (Delayed Lenz Effect) for a diametric magnet spinner at twenty five thousand RPM. I measured my spinner speed with a piece of reflective tape attached and a laser tachometer.  Itsu apparently lowered the CMF for DLE to a veritable 18,000 RPM with his resonant output coil. This amounts to an achievement, but I think Conradelektro will encounter slow down at 10,000 RPM.

I check my input with a digital ampmeter.