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Author Topic: RESONANCE EFFECTS FOR EVERYONE TO SHARE  (Read 298223 times)

gotoluc

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Re: RESONANCE EFFECTS FOR EVERYONE TO SHARE
« Reply #495 on: February 04, 2009, 04:00:18 AM »
Hi Duff,

great post ;)

Thank you for being the first to post a replication attempt.

First thing I would say is your primary is much longer than mine (just about twice) and I think this could be a major factor and maybe also wire gauge could have an effect. The next thing is maybe get the same bulb I'm using as load.

Please PM me your address and I will see if I can afford to send you a complete primary and secondary with bulb for you to test.

What I will also do is go to my uncle's computer engineering business and have him check my measurements with his equipment just to make sure my scope is reading things correctly.

That is about all I can think of at this time.

Luc


duff

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Re: RESONANCE EFFECTS FOR EVERYONE TO SHARE
« Reply #496 on: February 04, 2009, 08:29:49 AM »
@all

I want to post a simulation of Luc's circuit (last video) in an attempt to show what I believe is something unusual about the results that Luc is getting.

The simulation shows approximately 0.66Vpp output across R_Lamp, which has a value of 66.6 ohms and was calculated from the scope readings in the last video.

My test results were the same as the simulations.

Luc was getting 3Vrms across that bulb, which is 2.767Vrms more than the sim.

-Duff

[Edit]

The red numbers in the schematic are the node numbers.
Look at the waveform Legend to determine where the wave form was taken.
Single numbers in the Legend, example V(1), is node 1 with reference to ground

gyulasun

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Re: RESONANCE EFFECTS FOR EVERYONE TO SHARE
« Reply #497 on: February 04, 2009, 02:49:40 PM »
Hi Duff,

Would you mind running the simulation with a small modification, just to check the following:

R_dummy=1e12  (and not 1e-12)   and connecting it between node points 5 and 0.

Maybe you will get the same results in the simulation but normally you would not put a short circuit (1e-12) between nodes 5 and 3 in practice,  3 being the most sensitive point of the resonant circuit.

In Spice based simulations the dummy resistors are of GigaOhm values, that is what I used to include, to get rid of the ground independent nodes in a circuit.

Thanks,  Gyula

EDIT:  just thought of it: why there is no sinusoidal waveform (or nearly sinusoidal) across the lamp?  Values of L1 and C1 do give indeed 0.5MHz resonance but your pulse generator gives out 54.7kHz??   (PER = 18.28us)  Is that so?

duff

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Re: RESONANCE EFFECTS FOR EVERYONE TO SHARE
« Reply #498 on: February 04, 2009, 07:42:09 PM »
Hi Duff,

Would you mind running the simulation with a small modification, just to check the following:

R_dummy=1e12  (and not 1e-12)   and connecting it between node points 5 and 0.

Maybe you will get the same results in the simulation but normally you would not put a short circuit (1e-12) between nodes 5 and 3 in practice,  3 being the most sensitive point of the resonant circuit.

In Spice based simulations the dummy resistors are of GigaOhm values, that is what I used to include, to get rid of the ground independent nodes in a circuit.

Thanks,  Gyula

EDIT:  just thought of it: why there is no sinusoidal waveform (or nearly sinusoidal) across the lamp?  Values of L1 and C1 do give indeed 0.5MHz resonance but your pulse generator gives out 54.7kHz??   (PER = 18.28us)  Is that so?

Hi Gyula,

Thanks for your input. You have a keen eye...

Yes, I should have used R_dummy=1e12, my mistake. I was thinking inductors rather than transformers...

Also I do need to adjust the period.

Right now I experiencing some quirks with ngspice that I need to work through but I will update the above posts when I get that worked out.

Thanks,

-Duff

[EDIT]
I can no longer modify the above post so I have reposted the revised data below.

The updates look more in line with what Luc in reporting
He did not and probably could not give the waveform across the primary due to the USB Scope input limitations.
However, I was not getting that kind of voltage, so maybe that's why I was not getting his results.

[EDIT]
Update a mistake in netlist - changed R_Lp from 0.25 to 2.5 ohms
This really didn't make a difference in the waveforms - yes probably affected the circuit Q.
Although not shown below I did try decreasing the coupling between the coils to 0.60. that resulted in an increase in amplitudes which is less believable.
« Last Edit: February 05, 2009, 04:21:51 AM by duff »

gyulasun

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Re: RESONANCE EFFECTS FOR EVERYONE TO SHARE
« Reply #499 on: February 04, 2009, 11:25:32 PM »
Hi Duff and all,

Thanks for the modifications,  now simulation is improving.  ;) 

First thing is I would expect Luc to confirm your schematics in that he also connected his components exactly like that. He did not mention though he objected your schematics I assume it is the same as he built it.

Two other thing in your simulation: 
1) Luc uses a signal generator that I assume has got a 50 Ohm output impedance and I wonder if you included it in your simulation as the inner impedance of your generator?
2) The coefficient of coupling (k) between your L1 and L2 can significanly influence the output towards load resistance (i.e. the bulb)  so I wonder what value you used in the simulation?  Seeing the photo of your coils I would say 0.5 - 0.6 for (k),  a rough guessing of course.  You (and probably Luc too) may have noticed when moving a little one of the coils away from or closer to the other, the output power (hence the brightness of the bulb) is changing accordingly.

My understanding on this setup in general is that the problem is how to utilize reactive power circulating in resonant circuits and the answer is not that easy at all:  at the moment I can only suggest studying Hector's rotoverter setups because the problem basically is the same, there are already so called "peak extraction" circuits that seem to be able to do it (at least in paper) but no any report on a successful VAR power extraction yet... 
Member esaruoho at energetic forum has addressed this same problem just today, his posts #235 and #236
http://www.energeticforum.com/renewable-energy/1507-roto-verter-8.html

Regards,  Gyula

EDIT:  just noticed you use R_lp=0.25 Ohm for the primary coil copper resistance and Luc stated 2.5 Ohm, right?  This has significance in simulation only if you did not use a 50 Ohm generator inner impedance because the figure of merit (i.e. the Q quality factor of L1)  comes out much higher in that case.

duff

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Re: RESONANCE EFFECTS FOR EVERYONE TO SHARE
« Reply #500 on: February 05, 2009, 12:21:30 AM »
Hi Gyula,

Thanks again for your input.

Two other thing in your simulation: 
1) Luc uses a signal generator that I assume has got a 50 Ohm output impedance and I wonder if you included it in your simulation as the inner impedance of your generator?

No, I did not account for that.

Actually I've never thought about how I would do that. If you could provide an example I would appreciate seeing how that is handled.

Quote
2) The coefficient of coupling (k) between your L1 and L2 can significanly influence the output towards load resistance (i.e. the bulb)  so I wonder what value you used in the simulation?  Seeing the photo of your coils I would say 0.5 - 0.6 for (k),  a rough guessing of course.  You (and probably Luc too) may have noticed when moving a little one of the coils away from or closer to the other, the output power (hence the brightness of the bulb) is changing accordingly.

Actually that was listed in the deck file:
k1 l1 l2 .9

I know that was too high  but the intentions were to just get close enough to give some kind of a base line as to what should be expected.

Moving the secondary up or down and optimizing its position relative to the current nodes along the primary is also a factor especially with the longer inductors.

Quote
My understanding on this setup in general is that the problem is how to utilize reactive power circulating in resonant circuits and the answer is not that easy at all:  at the moment I can only suggest studying Hector's rotoverter setups because the problem basically is the same, there are already so called "peak extraction" circuits that seem to be able to do it (at least in paper) but no any report on a successful VAR power extraction yet... 
Member esaruoho at energetic forum has addressed this same problem just today, his posts #235 and #236
http://www.energeticforum.com/renewable-energy/1507-roto-verter-8.html

Regards,  Gyula

EDIT:  just noticed you use R_lp=0.25 Ohm for the primary coil copper resistance and Luc stated 2.5 Ohm, right?  This has significance in simulation only if you did not use a 50 Ohm generator inner impedance because the figure of merit (i.e. the Q quality factor of L1)  comes out much higher in that case.

Yes, another slip of the pen. It was the wee hours of the morning when I did that sim -

Here's what I think I've determined...

As I stated before, in my replication attempt did not achieve the high voltages the simulation displays and my primary was not the same geometric shape as Lucs. If I rewind that inductor and get those kinds of voltages then it is says a lot about the geometry. Then perhaps I'll get the same output across the load.

Well, it's time to start winding inductors again....

-Duff

[Edit]
I corrected the error with the value of R_Lp on the previous page.
Also - left a comment regarding the coupling factor.
« Last Edit: February 05, 2009, 04:27:16 AM by duff »

najman100

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Re: RESONANCE EFFECTS FOR EVERYONE TO SHARE
« Reply #501 on: February 05, 2009, 06:12:36 AM »
I was just responding to Gotuluc asking for our opinions , that is my opinion .

I like Gotoluc , he is Canadian ...


yeah write  ;D ;D ;D ;D go back to ionizationx and stay there and crack stainly meyers and as i told you i will build a monument for you in LAVAL .

Najman

dankie

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Re: RESONANCE EFFECTS FOR EVERYONE TO SHARE
« Reply #502 on: February 05, 2009, 06:58:47 AM »
yeah write  ;D ;D ;D ;D go back to ionizationx and stay there and crack stainly meyers and as i told you i will build a monument for you in LAVAL .

Najman

Sure , I feel ppl are smarter there ...

Have fun with the "resonance" , maybe add some "vacuum" while your @ it ...










« Last Edit: February 05, 2009, 07:21:43 AM by dankie »

gyulasun

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Re: RESONANCE EFFECTS FOR EVERYONE TO SHARE
« Reply #503 on: February 05, 2009, 10:45:43 AM »

No, I did not account for that.  Actually I've never thought about how I would do that. If you could provide an example I would appreciate seeing how that is handled.

Hi Duff,

Well,  if you simply connect a 50 Ohm resistor directly in series with your pulse generator in the schematic then you are done with this.  Normally spice based simulators use voltage source models with zero Ohm inner impedance so that they approach the ideal source with no any voltage drop across them and the user can choose any generator inner resistance.

Quote
Actually that was listed in the deck file:
k1 l1 l2 .9

I know that was too high  but the intentions were to just get close enough to give some kind of a base line as to what should be expected.

Now it was surely my turn to miss on that in your netlist :)  ;D :)

Quote
[EDIT]
Update a mistake in netlist - changed R_Lp from 0.25 to 2.5 ohms
This really didn't make a difference in the waveforms - yes probably affected the circuit Q.

Yes it affects the resonant circuit Q but as I already indicated the moment you include the 50 Ohm gen resistance, the Q  will degrade significantly in the resonant circuit so you will not get those skyhigh voltage values across L1.  (In fact the generator should feed either a tap on L1 or another coupling coil as a matching means between 50 Ohms and the resonant impedance, this would be the first to achive for Luc also and the second goal is to match the lamp's impedance to the resonant circuit with L2 number of turns at a fixed coupling.)

Quote
Although not shown below I did try decreasing the coupling between the coils to 0.60. that resulted in an increase in amplitudes which is less believable.

But it is believable in case of the primary coil because reducing the coupling means less load on the primary hence its resonant impedance can increase, so can the voltage across it too.  In case of the secondary coil the output voltage (hence power) should decrease as the coupling decreases.

Regards,  Gyula

duff

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Re: RESONANCE EFFECTS FOR EVERYONE TO SHARE
« Reply #504 on: February 05, 2009, 11:39:49 AM »
Hi Gyula,

First - Thank you very much for your assistance and  insight with this simulation. I understand what you are saying, I just have not worked with spice that much - but I'll get up to speed. I'll try to do further updates tomorrow if this board doesn't cutoff my ability to modify that post...


@all

Some good news -

I rewound my inductors with #28 wire. This is a little smaller that Luc used but I am now getting results.

Here are the specs on the primary.
Turns: 145
L = 1.38mH & 1KHz
R = 8.26Ω

Secondary:
Turns: 9 , #18 speaker wire
L = 8.75uH @ 1KHz
R = 0.060 ohms


The coil form dimensions were as Luc specified on the previous page (Reply #49 )

The output is 1/2 wave rectified and filtered with a 10uF cap

Freq: 305KHz
RLoad = 63.3Ω
VLoad = 3.221V
ILoad = 50.885mA
POut = 163.9mW

Of course the above means nothing without the input numbers which are going to be more complicated because I have a real ugly waveform across my 0.68 ohm series resistor which I using to calculate the current (circuit driven with only function generator).

-Duff

gyulasun

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Re: RESONANCE EFFECTS FOR EVERYONE TO SHARE
« Reply #505 on: February 05, 2009, 05:36:27 PM »
Hi Duff,

It would be better to use full wave rectification so that half of the output power be not lost.

You may wish to use a bridge made from 1N4148 or 1N914 diodes if you do not happen to have low power Schottky types.  (The best would be to have Germanium types  -1N34 or similar- to minimize forward voltage drop.)

Or as an alternative you may consider a not often used voltage doubler  which consists of two half wave rectifiers added together, see title "Rearranging the Doubler Circuit"  here:
http://www.play-hookey.com/ac_theory/ps_v_multipliers.html   Capacitor C1 has its positive leg on the common point of the diodes and C2 has its positive leg on D2 cathode of course and no need for a ground connection as the text suggests, it is a possibility for a reference point.    (Notice: I am aware of a voltage doubler does not double the power of course.)   The point is: this rectifier utilizes both half waves of the output voltage and uses only one diode for each half cycle, cf to a bridge where two diodes conduct in each half cycle.  You may use the full wave voltage doubler too of course, shown above the rearranged one.

rgds, Gyula

EDIT:  Although Luc mentioned his rectifier diode and puffer capacitor,  I cannot recall he used them, he did not use them in his video, so consider this to compare apples to apples...

gotoluc

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Re: RESONANCE EFFECTS FOR EVERYONE TO SHARE
« Reply #506 on: February 05, 2009, 05:57:00 PM »
Hi Duff,

it sounds like you're getting a better output.

Did you try your 0.68 ohm series resistor to calculate the current on either side of the Signal Generator to see if the noise level is less on one side then the other. I had the same thing but I used the side that is the cleanest. I also noticed if I unplugged the power to my laptop and use it on batteries to power it and the USB scope I would get a slightly cleaner form. I even connected my Signal generator to a inverter powered by a marine 12vdc battery and that also help clean noise. I can make the circuit work and test it completely off batteries!... which also eliminates noise or possible coupling.

BTW, I don't know at what size your capacitance is at to get your output of over 3 volts but keep in mind that too high a capacitance will reverse the resonant circuit savings. From all the tests I have done to date, there seems to be only one ideal (energy saving) capacitor size at a specific frequency for an inductor within a specific pulse generator circuit.

Thanks for all the time you're taking to research and share your findings.

Luc

Montec

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Re: RESONANCE EFFECTS FOR EVERYONE TO SHARE
« Reply #507 on: February 06, 2009, 12:03:15 AM »
Hello Duff
This may or may not apply to your coils but a Tesla Coil (TC) is usually made up of two air coils that have the same resonant frequency. The voltage increase/decrease is not based on the turns ratio but is based on a ratio of the inductance's of the two coils.  See http://www.scribd.com/doc/3876818/Denicolai-Tesla-Transformer-for-Experimentation-and-Research-96pp2001  for more info.

:)

duff

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Re: RESONANCE EFFECTS FOR EVERYONE TO SHARE
« Reply #508 on: February 06, 2009, 05:34:58 AM »
@Gyula,

Quote
It would be better to use full wave rectification so that half of the output power be not lost.

You may wish to use a bridge made from 1N4148 or 1N914 diodes if you do not happen to have low power Schottky types.  (The best would be to have Germanium types  -1N34 or similar- to minimize forward voltage drop.)

Luc used diodes in some of the previous videos. First I wanted to replicate his results before I started changing the circuit. Adding a FWB was the one of the first changes I was going to do to improve the output.

Luc had determined several weeks ago that SBL3040PT diode got the best results, so I built a FWB using them. I then compared the output with that of a 1n4148 FWB. The SBL3040 did the best job, however strangely the half-wave bridge performed better. Not what I expected...


1n4148 Full-Wave Bridge
3042 KHz - 3.018VDC

SBL3040 - Half-Wave Bridge
306.2 KHz - 3.59VDC

SBL3040 - Full-Wave Bridge
303.2 KHz - 3.285VDC

All were using a 330V 80uF capacitor from a disposable camera


Take a look this video Luc previously posted. It  immediately caught my attention, Why? Because Luc charges 12,000 uF caps almost instantly from the secondary using a 1/2 wave bridge with the SBL3040.


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


@Luc

Quote
BTW, I don't know at what size your capacitance is at to get your output of over 3 volts but keep in mind that too high a capacitance will reverse the resonant circuit savings. From all the tests I have done to date, there seems to be only one ideal (energy saving) capacitor size at a specific frequency for an inductor within a specific pulse generator circuit.

Initially I used a 10uF cap with the SBL3040PT diode and was getting the 3.221V out, however now I have a 330V 80uF cap in the circuit. I'm still getting about the same voltage but I was trying to smooth out some of the ripple.

It seems you have to increase the magnetic flux density within an small area. I think that's why my taller inductors were not working even though they had little higher inductance. If you remember the output was only 0.66V

I know you did some experiments with the flat bifiliar spiral but I might try a few more being I already have a small one wound.

Quote
Did you try your 0.68 ohm series resistor to calculate the current on either side of the Signal Generator to see if the noise level is less on one side then the other. I had the same thing but I used the side that is the cleanest.

Moving the current sensing resistor to the other end of the circuit places it at the positive lead of the function generator. Then when you connect your probe and ground lead across the resistor you introduce a ground in the middle of your circuit. That upset things...


Below are a few images. I wanted to show the wave form across the 0.68 current sensing resistor which for me presents a problem of calculating input current.

The voltage is now up to 3.281V. Last night I reported 3.221 but I did not have the function generator amplitude turned up all the way.

As stated above I've got a FWB in place.
Voltage input from SG is 25Vpp / 8.84rms

-Duff


[EDIT]
The text in the scope wave form image came out too small to read but it is the waveform across a 0.63 ohm resistor.
1uS/Div
1V/Div D/C

The one below says: Voltage across a 66.3 ohm resistor: 3.281V

gotoluc

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Re: RESONANCE EFFECTS FOR EVERYONE TO SHARE
« Reply #509 on: February 06, 2009, 06:27:01 AM »

Luc had determined several weeks ago that SBL3040PT diode got the best results, so I built a FWB using them. I then compared the output with that of a 1n4148 FWB. The SBL3040 did the best job, however strangely the half-wave bridge performed better. Not what I expected...

1n4148 Full-Wave Bridge
3042 KHz - 3.018VDC

SBL3040 - Half-Wave Bridge
306.2 KHz - 3.59VDC

SBL3040 - Full-Wave Bridge
303.2 KHz - 3.285VDC

All were using a 330V 80uF capacitor from a disposable camera

Great job Duff ;D, I'm happy to see you also confirming my finding on the diode. I tried about 30 different kinds of diodes that I pulled out of old CRT monitors and it is quite surprising to see how well these SBL3040 do.

@Luc

Initially I used a 10uF cap with the SBL3040PT diode and was getting the 3.221V out, however now I have a 330V 80uF cap in the circuit. I'm still getting about the same voltage but I was trying to smooth out some of the ripple.

The information I posted was about the capacitor within the primary LC.

It seems you have to increase the magnetic flux density within an small area. I think that's why my taller inductors were not working even though they had little higher inductance. If you remember the output was only 0.66V

I think that maybe part of it ;D. Also try raising your secondary by hand and see if it gives you a better output at a certain location but also keep an eye on the input so you don't use more power. Once you find the sweet spot place some non metallic supports to keep it there. That is why in my last video I have supports on the bottom of my secondary ;)

I know you did some experiments with the flat bifiliar spiral but I might try a few more being I already have a small one wound.

Sounds good. Please let us know what you find good or not.

Moving the current sensing resistor to the other end of the circuit places it at the positive lead of the function generator. Then when you connect your probe and ground lead across the resistor you introduce a ground in the middle of your circuit. That upset things...

Good point. Maybe I was able to do it when working my scope on laptop battery ???

Below are a few images. I wanted to show the wave form across the 0.68 current sensing resistor which for me presents a problem of calculating input current.

Yes, I see what you mean :'(.... this is why I got this USB scope... the software does the RMS surface calculations... I don't know how you can calculate that :P

Excellent post Duff ;D... thanks for sharing ;)

Luc