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Author Topic: Tuning multiple coils in close proximity  (Read 15180 times)
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I am trying to tune four coils to the same resonant frequency.

The coils are in close proximity.

Changing the inductance and or the capacitance of any of the coils changes the resonant frequency of all the other coils.

Anyone have a logical method for tuning multiple coils to the same resonant frequency?

It is driving me insane  :P

   
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Ds,

I have had a go at this for a short time

I used seperate isolation transformers for each coil and it drives one a little insane  but i didnt notice it much at the time .

The interaction is so complex I doubt that a theory exists. 2 was achievable 3 not.

If the frequencies are close they lock together dont they? Thought provoking!

It sure shows us a maze . I  would be interested also if any body has made a working strategy

   

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Buy me some coffee
Being a practical person, the only way i would try is to plot each coils change as each coil is altered, maybe try 3 different caps on each permutation of all the coils. and try to extrapolate the data graph to estimate the values, it sounds like a nasty job, Don did it with all identical coils.

Peter
   
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Peterae - thats a good idea.

At the moment I am thinking about stepper motors and a plc driving variable capacitors < but there must be a better way to do this by hand.

   

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tExB=qr
impulse or AC ?
   
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And what frequency ranges can you playing with.


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At the moment is is low

280khz @ 10kv

Testing in both pulsed dc into a primary tank and CW into a primary tank.

proximity of coils lowers the resonant frequency, the Q is real high so the threshold for resonant rise is very narrow.

I cant get within a foot of the system without it changing the resonant frequency of the system  :P



« Last Edit: 2010-03-26, 00:38:12 by darkspeed »
   
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I did it in this video

http://www.youtube.com/watch?v=tIaxci4SwaQ

But not at 10kv. Holy voltage Batman.

Why do you want to pulse at such high voltage.

What type of coils?

Maybe make a fifth coil of enough diameter to put the others inside it and make at least two or more turns then connect it to the others in parallel. That ring may act like a shield from outer influences, it will delimit a physical space for the others.


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Hello all,

@wattsup

nice video.

Always think about what I sayd a time ago: when you pulse a wire or a coil, particles are spreaded out of this wire/coil in ALL directions!!!

Otto
   

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At the moment is is low

280khz @ 10kv

Testing in both pulsed dc into a primary tank and CW into a primary tank.

proximity of coils lowers the resonant frequency, the Q is real high so the threshold for resonant rise is very narrow.

I cant get within a foot of the system without it changing the resonant frequency of the system  :P

Look at Dr Stiffler's work.  I have some friends that started with this and ran five receivers from one transmitter.   They didn't mention any tuning problems...

what are you using for a switch?
   
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My flyback driver, one of the coils is loose and three of the coils are tight coupeling so its a pain.

I have been drooling over the idea of four 10kv 1000nf vacuum variable capacitors driven by stepper motors from a plc - start program and go make coffee - i could use a four channel pc bitscope for the feedback. it is just more work...

   
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Hello All,

To successfully tune all the coils at slightly differing frequencies theres a 'trick' which you may not know of.
The trick is simple to explain but not so in the doing.
The 3 coils in this case need to be at EXACT NULL relative to each other.
Diagrammatically they appear as the three primary colours arranged to show central white and secondary intermixing twins....Sound familiar?
Using 2 to start. When the coils overlap the outside sends positive EMF induction and the inner sends negative EMF. At 1 EXTREMELY SENSITIVE and PRECISE point they totally (theoretically) cancel out.
In practise the coils have to be interleaved and this is almost impossible. 2 separate coils can be positioned first and fixed at the lowest point by resonating 1 (TX coil) and sensitive scope on the other (RX coil) for best null. When done, test 'em on 2 differing freqs. If you use a small local loop to scope input you should see intermixed freq on ssslllooowww timebase like AM transmission. You can have very small freq differences between the coils this way and they dont always lock BUT the oscillator has a lot to do with this...just enough gain to sustain as pure a sine as poss WILL help lots.
The 3rd coil is a basxxxxd to align, it WILL change the freqs of the others, it WILL upset the perfected balance setup but can be done by attaining the original freqs as a starting point then scope this coil for null. The freqs of the other 2 should be as originally setup if the 3rd is at perfect null. There is a massive phase shift with the smallest of offset from perfect null,  I have a GEB discriminator 1985 thats never been beat based on this. ;D
The first 2 are quite simple to setup but the 3rd .....try it   youll see....

Hope this helps

Steve.
   

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I was hoping one of you clever folks could answer this question in this video I made.

 I made it after watching wattsup's vid!!

[youtube]http://www.youtube.com/watch?v=VnKS1A1NBh0[/youtube]
   
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Hi ST,

It looks like meter error. There must be some RF getting in on the leads to it.
To drastically reduce it is quite simple.
Disconnect the resistor from the cct leaving the power wires ready for a new cct.
Connect in parallel across the 1 ohm resistor some caps. Suggest using 100 pF, 1nF, .01uF .1uF and 1uF.
Then connect one of the ends of the R/C cct to the + terminal of a bridge rectifier and then connect the other end to the - terminal.
The meter leads are connected across the resistor as before, taking note of the orientation.
The AC terminals of the rectifier are where the power wires now re-connect from the original resistor circuit.
There may be a small voltage drop to the circuit when using the rectifier this way but the accuracy of your readings will be better.

   
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@stprue

I am not the scientific guy here to better dissect the question.

But I do know that duty cycle adjustment can save you so much energy and get the same results. Seems like when the duty is too high you get a shorting effect on the toroid. To have any type of resonance, you need the right amount of free space around the resonating medium. To much duty is like putting your hand on the resonator while you hit it, not enough duty it like hitting it to lightly. I have found that between 9% and 20% is the best range, but sometimes from 12% you go up to 13% and it kills the effect.

Also, when you do instrument measurements on these types of very low voltage/amperage LED/COILS, let's say the LED is lit and you measure something, always remove the probe to make sure the LED is still lit without the probe on it to confirm the probe or DM clips itself is not contributing to the LED being lit.


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Thanks for the info's guys!  I will do more testing!
   

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Some more bucking coil tests!

I am able to power an led on one coil and power a circuit consisting of another led and charging a cap as well.

This is getting interesting!  Here are some photos!
   

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tExB=qr

My flyback driver, one of the coils is loose and three of the coils are tight coupeling so its a pain.

I have been drooling over the idea of four 10kv 1000nf vacuum variable capacitors driven by stepper motors from a plc - start program and go make coffee - i could use a four channel pc bitscope for the feedback. it is just more work...



Oh...well that's a little different

With a transmitter and 3 receivers, you are not coupled this way, so they can do their own thing - notice that the TX and RX are wound in opposite directions.

My friend did day that the mass of all receivers has to match the mass of the transmitter (final coils that is) - transmitted power is "copied" at each reciever.  By they way, the magnifier may be easier to replicate than Don Smith's work.
   
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Quote
notice that the TX and RX are wound in opposite directions.

Are you sure  ;) If you drew a circle through the transmitter and receiver, the top of the receivers connected by one arc of the circle to simulate the coupeling, then follow the arc along and you will see they are wound the same direction on a virtual axis of transmission.

So in a system like Don Smith they are all wound the same way on the same axis.

   

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Are you sure  ;) If you drew a circle through the transmitter and receiver, the top of the receivers connected by one arc of the circle to simulate the coupeling, then follow the arc along and you will see they are wound the same direction on a virtual axis of transmission.

So in a system like Don Smith they are all wound the same way on the same axis.


Pretty sure that is what my freind said - wound opposite.  I'll call him this week.

Tesla does show that the tx and rx are wound opposite.  When you draw a spiral ccw on a piece of paper, it becomes cw when you flip the paper over and the polarity flips with it.  Looking at the cap plates (top load and ground plates) - having the tx and rx flipped makes sense since the cap plates must be opposite to work.

I don't think the coils are coupled in a classical EM sense.

I am not convinced that Don's devices actually worked as he claimed.  I don't think Don uses capacitive coupling in any way and if the tx and rx are very close together, what is the point unless there is some mechanism of gain between them?
   
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You are correct if you are looking down on them they are wound opposite but if you look at them as a transmission line they are wound the same way on the same axis

looking down on them is looking at them from the center of the "virtual wire" capacitive coupeling connecting them

   

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tExB=qr

You are correct if you are looking down on them they are wound opposite but if you look at them as a transmission line they are wound the same way on the same axis

looking down on them is looking at them from the center of the "virtual wire" capacitive coupeling connecting them


I can not recall an instance where Tesla placed the tx and rx on the same axis.

Dollards balanced coil system which combines the TX and RX has the two halves wound opposite directions.

Coils couple magnetically when wound the same way and this may interfere with longitudinal coupling because the pattern is reflected back in your advantage is cancelled - hint hint.

The following is a comment by "Spherics" regarding the Molina-Martinez device:

Quote
Someone mentioned the Alberto Molina-Martinez device as being the same. It would
appear at a casual glancing at the patent to be chock full to the brim with iron/steel
and other magnetic materials which I have said ad nausium is a no-no. Also the 3
phase pickup coils use the same coil structure and location as the 3 phase generating
coils. As soon as the pickup coils are induced they will reflect a pattern in the ether
back on the generating coils and any advantage will be lost.
There are also no pulses
timed to cause an overlap of ether waves in the proximity of the pickup coil nor is there
any directional biasing
.
   
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G. you may be correct..

I am looking at E.D.'s notes and he says mirror coil (180deg shift) but it is drawn (by hand) to look like it is all the same direction  :-\

   

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tExB=qr
yep, and Tesla moved the halves of the mirror coil apart
   
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