Tesla's "COIL FOR ELECTRO-MAGNETS".

[tim123]

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...

[Farmhand]

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

 

[gyulasun]

@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

[gyulasun]

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

[synchro1]

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.