Tesla's "COIL FOR ELECTRO-MAGNETS".

[gyulasun]

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The coil with air core seems to have a maximum output over the 100 Ohm resistor at about 200 Hz, at 240 HZ it definitely puts out less, also below 200 Hz.
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Hi Conrad,

When you have some time, would you make a scope shot of the voltage and current when the air core coil have the max output with the 100 Ohm load at about 200 Hz?  If the shot is very similar to what you have so far showed just in the previous post, then of course no need to make it, just mention that.  (I am interested in the phase relationship under this condition.)

EDIT: A strange thing I observe: when you have a voltage max at about 52 Hz by the scope measurement (loaded case, with bolt, series bifi, motor input 4.4V/1.68A from your video ),  the 10 uF capacitor needs 936.7 mH coil inductance to get resonance at 52 Hz.  How is it possible I wonder, the bolt makes your series bifi coil to be 520 mH.

Thanks,  Gyula

[MileHigh]

Conrad:

What a beautiful setup you have!  I am going to be busy for a while so I can't say too much now.  I think I see the "light at the end of the tunnel" already though.  There are many tests you can make so have fun.  I can see you have a suggestion queue going also!

I have always said, when you make a change, the electromechanical impedance of the motor changes and you have to investigate that before drawing any conclusions.

Here are my first impressions:

The motor speeds up when you add the load, so that must mean the mechanical load, i,e.; the "back torque" from the coil decreases.

When I look at the coil in resonance I see the highest voltages and currents.  You know the coil resistance and the current sensing resistance and the RMS current.  So you can calculate the power dissipation in that system.  Note this is analogous to reactive power with resistive losses in the wiring.

When you add the load, you have all the resistances and RMS current.  We can see that the RMS current has dropped.  So you can calculate the power dissipation in this system.

As others have already said, it looks like the total power dissipation in the coil system goes down when you add the load. 

Therefore we can conclude that the rotor speeds up because the total power dissipation in the coil system goes down.  It's almost too obvious and it's amazing how a well run experiment can clarify things up.  With 20-20 hindsight some of these effects will seem obvious.

It would appear that an unloaded coil + capacitor at resonance is a power hog.  It makes perfect sense because the voltage and current increases at resonance, and that means you burn off more power in the coil itself.

Note of course that the belief is that it's (resonance + load) that gives you an advantage, and that is open to more investigation.  But we now know that a coil in "pure resonance"  (coil and cap but no load resistor) is actually a heavy load. (to be confirmed by someone crunching the numbers)

Anyway, that's a great start on your part.

Here is an advanced call on what we are seeing:  The "delayed Lenz effect" is really an impedance change in the coil such that it burns off less power with a load resistor added as compared to just resonating with no load resistor.  The reason many people were "thrown off the trail" is because when a (coil + cap) is in resonance alone (no load resistor) it actually acts somewhat akin to a "matched" load resistor.  i.e.; the voltage and current increase in the LC resonator to the point that the resistance in the coil wire itself becomes a nasty load on the motor.

I believe perhaps people believed that there was "almost no load" when there was no load resistor and "a bigger load" when they added a load resistor.  In fact, it was the opposite of what they thought.  It's happened before, some of these things are not obvious at all and it shows the value of "doing the experiments" with the caveat that you can't "just observe and draw up conclusions."  You have observe and then work the problem out and crunch the numbers and do A-B comparison testing and so on.

MileHigh

[Magluvin]

The thing I looked at with the speed up under load effect is the dismal output as compared to the input, overall a faster rotor is not output, the power dissipated by the load resistor is the output, and the input compared to that.

I think there is something with speedup under load. The question is why less load on the rotor when the pickup coil is loaded compared to unloaded? If we add another pickup coil, would the speedup not speedup so much as just 1 coil?

Romero had 16 pickups and had very good speedup. If speedup does reach the same rpm with 1 coil and more than 1 coil, then start adding coils till the output reaches or exceeds input.

Mags

[Farmhand]

Conrad:

What a beautiful setup you have!  I am going to be busy for a while so I can't say too much now.  I think I see the "light at the end of the tunnel" already though.  There are many tests you can make so have fun.  I can see you have a suggestion queue going also!

I have always said, when you make a change, the electromechanical impedance of the motor changes and you have to investigate that before drawing any conclusions.

Here are my first impressions:

The motor speeds up when you add the load, so that must mean the mechanical load, i,e.; the "back torque" from the coil decreases.

When I look at the coil in resonance I see the highest voltages and currents.  You know the coil resistance and the current sensing resistance and the RMS current.  So you can calculate the power dissipation in that system.  Note this is analogous to reactive power with resistive losses in the wiring.

When you add the load, you have all the resistances and RMS current.  We can see that the RMS current has dropped.  So you can calculate the power dissipation in this system.

As others have already said, it looks like the total power dissipation in the coil system goes down when you add the load. 

Therefore we can conclude that the rotor speeds up because the total power dissipation in the coil system goes down.  It's almost too obvious and it's amazing how a well run experiment can clarify things up.  With 20-20 hindsight some of these effects will seem obvious.

It would appear that an unloaded coil + capacitor at resonance is a power hog.  It makes perfect sense because the voltage and current increases at resonance, and that means you burn off more power in the coil itself.

Note of course that the belief is that it's (resonance + load) that gives you an advantage, and that is open to more investigation.  But we now know that a coil in "pure resonance"  (coil and cap but no load resistor) is actually a heavy load. (to be confirmed by someone crunching the numbers)

Anyway, that's a great start on your part.

Here is an advanced call on what we are seeing:  The "delayed Lenz effect" is really an impedance change in the coil such that it burns off less power with a load resistor added as compared to just resonating with no load resistor.  The reason many people were "thrown off the trail" is because when a (coil + cap) is in resonance alone (no load resistor) it actually acts somewhat akin to a "matched" load resistor.  i.e.; the voltage and current increase in the LC resonator to the point that the resistance in the coil wire itself becomes a nasty load on the motor.

I believe perhaps people believed that there was "almost no load" when there was no load resistor and "a bigger load" when they added a load resistor.  In fact, it was the opposite of what they thought.  It's happened before, some of these things are not obvious at all and it shows the value of "doing the experiments" with the caveat that you can't "just observe and draw up conclusions."  You have observe and then work the problem out and crunch the numbers and do A-B comparison testing and so on.

MileHigh

Well I have been saying almost that exact same thing for quite some time, mainly in the other thread, I've also said the speed up effect is an increased lenz effect that is decreased by the load, go figure. If the frequency is again adjusted then the output will increase as the resonance is "refound on load", it is something that must be done when getting power from activity in a tank, if the load drops the activity you need to readjust the circuit to get back as much of the activity as possible. Some loads can increase the activity if the system is slightly off resonance to begin with. The effect on the tank is no different to what I see in any resonant tank I load.

As I said the voltage and activity in the tank increase until it creates a significant parasitic load. Best way is to tune the circuit to the load till the proper output is gotten.

Once the maximum output on load frequency is established for that load then if the load is removed at that frequency the input will drop.  Is my assumption based on experience.
This is due I think to the fact that the circuit is adjusted to loaded "resonance" and when the load is removed it goes to a less than resonant condition, therefore the tank voltage and activity is less with no load and so the input is less.

We all know that a resonant tank will increase its voltage and activity to the point of loss, which is why a low loss tank is important if we use one like that.

I found I heated up 0.7 mm wire by a direct short when tuning to try to increase current under the dead short or even heavy load.

It is nice to see when a load is attached like a filament globe light right up by tuning after having it drop the activity and not light up. It shows the power of the resonance good resonance makes a hard voltage that will meet any load it can if adjusted.

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[Farmhand]

Here is a quick video that shows tuning the tank to the different loads and no load, the tank is excited by the transmitting transformer which is an AC generator, the tank I adjust is the output tank of the receiver coil, in this case the resonance of the transmitting and receiving coils are at play as well but are only slightly affected by the not so tightly coupled tanks. There was no tank on the transmitting coil as such, but when conducting the primary capacitance makes resonance on the primary of the transmitter, the transmitter tank is only a tank when the mosfets are conducting, not important, the effects are at the receiver. but the period can be changed at the transmitter to effect the same result. Easy, it can be tuned from either end, which shows changing the applied frequency or adjusting the L/C of the tank will re-tune the tank.

Tank tuning.
http://www.youtube.com/watch?v=jJgHWYTk6_g

This video shows the transmitter resonant waveform going to the receiver and the input drop under load ect. Same effect, same output tank style.
http://www.youtube.com/watch?v=Xcy-bGetZf0

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I'm certain if Conrad keeps experimenting he will be able to show almost every aspect of it with different effects when tuning the setup.

Another thing to try might be to setup a "series tank" with the load in the tank already and tune to best output to see any real difference between series and parallel loaded resonance. I must admit I did not try that.  The effect would be that resonance is only attained on load and with series resonance, until the load is attached there is no tank.

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So much for infinite impedance of a parallel tank. What it means in practice is higher input with no load not lower as many Like Duncan from EF tout.

With a solid state setup if the system is out of tune when no load but in tune when on load then the input is very small with no load (out of tune) , then when the load is added it becomes what tunes the tank and input will increase. It is all a matter of tuning for output. That's why they call them "tuned circuits" to get the most from them they must be tuned.

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I think when loaded the inductance drops in the tank. like shorting a second coil on a regular transformer drops the inductance of another wound on the same core.

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