Tesla's "COIL FOR ELECTRO-MAGNETS".

[conradelektro]

I made a new exciter coil with 4 turns (see the attached photo) which is now in the right orientation in respect to the pan cake coil. Because it is fixed to a central plastic bolt of the pan cake coils it can be mounted at exactly the same position at both pan cake coils.

Measurements gave about the same results as in this video http://www.youtube.com/watch?v=spQ9yLdb7v4&feature=youtu.be

In addition I tried the "Inductor Capacitance and Inductance Estimation with the two frequencies method" according to this web site http://www.qsl.net/in3otd/inductors.html (with the new exciter coil and two different tank capacitors).

This method needs two measurements with two different tank capacitors (see the attached drawing). The estimate for the inductance is pretty good, also for the self capacitance of the bifilar coil. The self capacitance of the monofilar is estimated a bit low (2 pF instead of 7 pF to 9 pF).

The 1 pF decoupling capacitor (for the scope probe) is very important, the "two frequencies method or estimation" gives very bad results without it. All measurement methods need the 1 pF decoupling cap to work well. The involved frequencies are high enough (about 1 MHz to 9 MHz) to be disturbed by the scope probes input capacitance of about 100 pF.

This concludes the measurement of

- induction ~34 µH for both pan cake coils (with a LCR-meter and the "two frequencies estimate")

- self resonance (bifilar coil ~4 MHz, monofilar ~ 9 MHz) and the resulting self capacitance (bifilar ~45 pF, monofilar ~7 pF) with two methods:

      * the classical method (resistor in series with the pan cake coil see video http://www.youtube.com/watch?v=fC84W0PIZoE
      * the exciter coil method (see video http://www.youtube.com/watch?v=spQ9yLdb7v4&feature=youtu.be and attached drawing and photo)

Together with the spin tests (pick up coil quality) and the magnetic field measurement (video http://www.youtube.com/watch?v=gCEqnX1JsGw) we now have already some tangible facts about pan cake coils (bifilar and monofilar).

The magic difference is still elusive. What is the magic difference or the magic effect (in understandable terms, I know about the Voltage between neighbouring wires and the difference in self capacitance)? How can the magic be measured (without exotic equipment)?


I will work a bit on my 12 V motor spinner (new coupling between motor and axis carrying the ring magnet, should then do 10.000 rpm) and will prepare forms for helical coils (one bifilar the other monofilar, otherwise identical).

Does it make sense to start with "one layer helical coils" or should I go directly to helical coils with many layers of windings? The core will be 10 mm and can then be in a changeable way an air core, a Ferrite core and a soft iron core (bundle of iron wire sticks).

Greetings, Conrad

[Magluvin]

@Mags:

What do you mean by "very high freq initial spike". Please look at the drawing, I think you meant a "pulse of short duration"? Do you mean that one should send a short pulse through the pan cake coil? If you mean that, what should be the "astonishing effect"?

Again, I am not criticising, just trying to understand and later on trying to reproduce the alleged effect.

Greetings, Conrad

P.S.: A measurement can not be cheap, it can only be correct or incorrect. Why the insults? I am not attacking, I am measuring and then I am being attacked.

"What do you mean by "very high freq initial spike"

With the capacitance of the coil, the initial current is high, even with DC input. The coils capacitance takes on initial current regardless of inductance, and only lasts for 1 half of the resonant cycle. So at 4mhz, the scope would have to be set up to see it. If the source is a batt, then a cap across the batt should show a bit higher spike than batt alone, giving a more immediate input as batts cant discharge as much immediate current as a cap.

Say if we have a cap and coil in series and apply dc, the inductance of the coil will impede charging the cap. So having the capacitance in the coil is a bit special.


"P.S.: A measurement can not be cheap, it can only be correct or incorrect. Why the insults? I am not attacking, I am measuring and then I am being attacked."

The measurement advice you followed was concocted to show nothing special.  Especially with coils that would be impossible to get into resonance using a pulse motor and way out of range for seeing anything with DC testing without really looking. The tests were what they were. You were just 'following' instructions that were not from the person who gave you the coil designs to test.  And you found nothing special.

There is no 'magic'. It all can be defined.  The bifi gives us options that are not exactly the same as separate components.

Mags

[conradelektro]

With the capacitance of the coil, the initial current is high, even with DC input. The coils capacitance takes on initial current regardless of inductance, and only lasts for 1 half of the resonant cycle.

................ So at 4mhz, the scope would have to be set up to see it. ..................

If the source is a batt, then a cap across the batt should show a bit higher spike than batt alone, giving a more immediate input as batts cant discharge as much immediate current as a cap.

Say if we have a cap and coil in series and apply dc, the inductance of the coil will impede charging the cap. So having the capacitance in the coil is a bit special.

What exactly should be seen by the scope and how should it be set? (I am talking about the difference between my monofilar and bifilar pan cake coils. The "synchro coil" is no longer on my agenda and not part of this thread, it needs a different type of person than me.  You could do a "synchro coil", you seem to believe in it.)

The measurement advice you followed was concocted to show nothing special.  Especially with coils that would be impossible to get into resonance using a pulse motor and way out of range for seeing anything with DC testing without really looking. The tests were what they were. You were just 'following' instructions that were not from the person who gave you the coil designs to test.  And you found nothing special.

So, give measurement instructions! What should be measured and how? (I am talking about the difference between my monofilar and bifilar pan cake coils.)

What wrong instructions have been given in connection with my monofilar and bifilar pan cake coils and their measurement?

Greetings, Conrad

[Magluvin]

Was putting some thoughts together today.

Below, once more, Im posting the pdf that explains how flux propagates through a closed transformer core(toroid). Helps to understand the second pdf.

The next pdf shows how to add a second magnetic circuit with the secondary that when you load the secondary, the input currents actually go down. No magic here. And no extra power out as the pdf states. But, what the pdf does claim is that loading the secondary wont kill off the 'resonance' of the primary.

I have tested the dual core and yes it does decrease the input of the primary when the sec is loaded due to 'increasing' inductance of the primary instead of the standard which decreases primary inductance when the sec is loaded, but output power is no more than the input.   I still have to test a bifi primary here to see if resonance of the primary is not killed off by a loaded sec.

In my experience, when we apply an input to a resonant circuit, we see higher voltages than the input itself at resonance. But direct loading kills of the resonance.

But here with the dual core setup in the second pdf, we may be able to take advantage of that resonant rise without killing it off with loading of the sec.

Mags

[Magluvin]

What exactly should be seen by the scope and how should it be set? (I am talking about the difference between my monofilar and bifilar pan cake coils. The "synchro coil" is no longer on my agenda and not part of this thread, it needs a different type of person than me.  You could do a "synchro coil", you seem to believe in it.)

So, give measurement instructions! What should be measured and how? (I am talking about the difference between my monofilar and bifilar pan cake coils.)

What wrong instructions have been given in connection with my monofilar and bifilar pan cake coils and their measurement?

Greetings, Conrad

"What exactly should be seen by the scope and how should it be set? (I am talking about the difference between my monofilar and bifilar pan cake coils."

With a straight DC application to the coil, the scope would have to trigger and show the initial current flow. This would be a 1 shot scope shot. Cuz after that, its just a DC trace.

Me personally, I have no use for coils that work in the radio range. Not that someone might be able to use them for something, but I tend to like below 100khz. And if we are interested in using bifi in a motor, the coil needs lots of turns. Im surprised you were able to measure actual capacitance of the normal coil. My 'meters' tend to show quite high capacitance of a regular coil, of which is not accurate. The only way I know of is to calculate using freq of resonance and inductance to get accurate capacitance. Maybe some meters can measure it. Of the 3 I have, I cannot.

The more turns of a regular coil, the more the capacitance between the 2 leads of the coil is just a bunch of series capacitances between turns. In a bifi coil, the more turns is directly related to an increase in parallel capacitance between the bifi turns. 

So the differences between your coils(in the uh and pf) seem like nothing special. But the more turns, the more of a difference you should see.

Say we have a 2 turn coil. It can be considered a normal coil. But it is also the exact definition of Teslas bifi. Example, if we apply 10v across the 2 turn coil, at any point on the 2 turn coil we can measure 5v difference from 1 turn to the next. 1/2 the input.

So now say we have a 10 turn coil, normal and bifi coils.  The normal coil, 10 turns, with 10v across the coil, we can measure any adjacent turns and we will see 1v, but the bifi will see 5v.

100 turns, normal coil .1v between adjacent turns, bifi still 5v between adjacent turns.

So the more turns, the more the difference.  1000 turns, .01v between adjacent turns, bifi 1000 turns, still 5v between adjacent turns.  That 5v between turns(capacitive) is a heck of a lot more energy than .01v between the yet smaller capacitance of the normal coil.

So, though they are very nice coils you have made, they will show minimal differences compared to many turn coils. In the pat, I and some others believe the illustration of pancakes was to easily describe that actual wiring differences. Simple to see. And the pat states that the bifi can be configured to any style of coil.



"So, give measurement instructions! What should be measured and how? (I am talking about the difference between my monofilar and bifilar pan cake coils.)"

Explained above. What we are interested in is working the coils at resonance. Not below, nor above freq of resonance.


"The "synchro coil" is no longer on my agenda and not part of this thread, it needs a different type of person than me.  You could do a "synchro coil", you seem to believe in it.)"

I dont believe in the Syncro coil 'yet'. Have I stated that somewhere? I have not tried it. But if I did, I would make sure I replicated it to spec to try to get the most accurate comparable results as possible. Any difference could throw things way off and may not work at all. I would like to see more before I delve into it. I asked you earlier about Syncros accusation that you didnt test the Synchrocoil properly, but no response. He claims you didnt use the diode. I can see why you got nothing into the cap. Did you use the cap or just a resistor load? If it is very high freq ac, even very low voltage, the cap alone would need to be very tiny and equipment to have the ability to read such AC ghz on the cap. With the diode, the coil would charge the cap with dc, which would make it easier to 'see' what is in the cap without special equipment. From what I understand.


Mags