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Author Topic: Lenzless resonant transformer  (Read 184721 times)

Magluvin

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Re: Lenzless resonant transformer
« Reply #90 on: February 28, 2014, 04:12:30 AM »
12 watts circulating in the tank, still it cannot light that tiny bulb. Bulb resistance seems to affect this, maybe it causes voltage to drop in capacitor and energy cannot be used ?

Hey Jack

Is the light bulb in series with the cap and inductor, or in parallel?

Mags

Jack Noskills

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Re: Lenzless resonant transformer
« Reply #91 on: February 28, 2014, 07:58:45 AM »
Jack:

I am not sure what you are talking about here.

The energy in a capacitor is 1/2*C*V*V.    "Q" is used for charge, not capacitance.   The energy crunches out to 99.3 micro-joules of energy.  That's what's circulating in the tank.  What do you mean when you say "12 watts," that doesn't make sense!  We are talking about energy in the tank, not power.

I know it's kind of politically incorrect to correct other people sometimes.  But if people don't correct each other then you have stagnation, and you end up spinning your wheels and making the same errors over and over.   My advice to you is to find a good YouTube channel for beginning electronics instruction.  Watch every clip in the channel until you get it.  Then move onto an intermediate YouTube channel for electronics instruction.

Please don't get offended, I am giving you sound advice.

MileHigh


Ups, I mixed Q with C and dropped the 1/2. Ok, so 99.3 micro joules of energy. This bounces 2*62000 times back and forth via inductor in LC circuit during one second, about 12 joules. I recall that one joule is one watt for one second, so isn't this then 12 watts for one second ?

Jack Noskills

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Re: Lenzless resonant transformer
« Reply #92 on: February 28, 2014, 08:12:58 AM »
Hey Jack

Is the light bulb in series with the cap and inductor, or in parallel?

Mags


I think itsu put the bulb in series but it was not shown in the video. Q-factor depends on the inductive reactance divided by DC resistance of the coil. If we put load there, then it will also increase DC resistance, which decreases Q-factor and hence drops voltage. Not sure but this would make sense.


The inductance of the 100 turn coil was 1 micro henry, to resonate this at 62 kHz there would have to be over 6500 nf worth of capacitors, but 5.5 nf was sufficient. I am now puzzled why. When this coil is used as primary then to resonate it at 62 kHz more caps are needed. Maybe easier to put 220 nf in the secondaries, measure resonant frequency of that and then match the primary to that frquency.


BTW, inductance of those two 200 turn secondary coils combined was about 0.4 mH. itsu, what is the core area dimension ? We know that core has 1000 permeability, now I am thinking would this 0.4 mH be inductance of solenoid of the same size. Looped flux is cancelled but solenoid flux still left ?

itsu

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Re: Lenzless resonant transformer
« Reply #93 on: February 28, 2014, 10:24:21 AM »

I think itsu put the bulb in series but it was not shown in the video. Q-factor depends on the inductive reactance divided by DC resistance of the coil. If we put load there, then it will also increase DC resistance, which decreases Q-factor and hence drops voltage. Not sure but this would make sense.


The inductance of the 100 turn coil was 1 micro henry, to resonate this at 62 kHz there would have to be over 6500 nf worth of capacitors, but 5.5 nf was sufficient. I am now puzzled why. When this coil is used as primary then to resonate it at 62 kHz more caps are needed. Maybe easier to put 220 nf in the secondaries, measure resonant frequency of that and then match the primary to that frquency.


BTW, inductance of those two 200 turn secondary coils combined was about 0.4 mH. itsu, what is the core area dimension ? We know that core has 1000 permeability, now I am thinking would this 0.4 mH be inductance of solenoid of the same size. Looped flux is cancelled but solenoid flux still left ?


Jack,

be aware that the L3 coil is 1mH as in milli,  not micro!

As for the core area dimension, see here where it says:

Quote
the od (65mm), the id (40mm), the thickness (9mm)

I made a video of some current / voltage measurements on this 3 coil setup, but need some time to comment in it, will be up later today.

Regards Itsu
« Last Edit: February 28, 2014, 03:21:34 PM by itsu »

verpies

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Re: Lenzless resonant transformer
« Reply #94 on: February 28, 2014, 01:31:58 PM »
Ups, I mixed Q with C and dropped the 1/2. Ok, so 99.3 micro joules of energy. This bounces 2*62000 times back and forth via inductor in LC circuit during one second, about 12 joules.
You are ignoring the direction (sign) of energy flow (a.k.a. power).

I recall that one joule is one watt for one second, so isn't this then 12 watts for one second ?
Rather it is 99μJ per 8μs (½ period of oscillation) which is equivalent to +12.3Watts for ½ cycle of the oscillation ...and 0Watts for 1 full oscillation.

itsu

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Re: Lenzless resonant transformer
« Reply #95 on: February 28, 2014, 01:33:58 PM »
Ok,

i made some voltage/current measurements on this 3 coil setup, in which we have much voltage/current running around in the L3 tank coil, but because the voltage/current is out of phase they do not exceed the input power from the FG.

Video here:  https://www.youtube.com/watch?v=NKEFILwZ10Y&feature=youtu.be

Next i will use the L3 as primary and make some measurements that way.

Regards itsu

verpies

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Re: Lenzless resonant transformer
« Reply #96 on: February 28, 2014, 01:38:49 PM »
.

itsu

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Re: Lenzless resonant transformer
« Reply #97 on: February 28, 2014, 02:09:50 PM »
.

verpies

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Re: Lenzless resonant transformer
« Reply #98 on: February 28, 2014, 02:49:29 PM »
I made some voltage/current measurements on this 3 coil setup,
If this large 3rd coil was physically rotated 90º so it would be encompassing both the primary and the secondary windings, then you would be able to detect the induction caused by the leakage flux spilling out of the core.  The more current flows in secondary, the more voltage is induced in this 3rd winding. 
It is just a neat trick to detect how much flux leaks out of a transformer's core.  It has a large educational value.

P.S.
As always, the even number of layers of back&forth winding rule designed for pitch-current nullification, applies to all windings.

verpies

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Re: Lenzless resonant transformer
« Reply #99 on: February 28, 2014, 04:30:57 PM »
but because the voltage/current is out of phase they do not exceed the input power from the FG.
Video here:  https://www.youtube.com/watch?v=NKEFILwZ10Y&feature=youtu.be
It is interesting to watch the red math trace (power) on this video as you adjust the frequency.
Sometimes most of this waveform is above the X-axis* and sometimes it is below it.
Anything above the X-axis means that energy is flowing from the signal generator to the device under test (DUT)
...and anything below the X-axis means, that the DUT is returning energy to the signal generator.

The total area taken by the red power waveform above/below the X-axis, means the amount of energy that has been transferred. 

For example:
On the scopeshot below it can be seen that the blue areas are greater than the yellow areas, despite that the red waveform has 4x higher amplitude above the X-axis than below it. 
For this scopeshot, this means that more energy is returned to the power supply than taken from it.


*the X-axis is denoted by the red channel zero-marker at the left margin of the scope's screen
« Last Edit: February 28, 2014, 07:10:04 PM by verpies »

itsu

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Re: Lenzless resonant transformer
« Reply #100 on: February 28, 2014, 04:57:48 PM »

Quote
...and anything below the X-axis means, that the DUT is returning energy to the signal generator.

like negative resistance, a negistor?

Or do we have here a severe case of reactive power versus real power?
Guess that the returning energy never will be more then half of the total energy

Thanks,  regards itsu

verpies

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Re: Lenzless resonant transformer
« Reply #101 on: February 28, 2014, 05:09:30 PM »
like negative resistance, a negistor?
No, no ...more like a charged capacitor discharging itself back into the signal generator.
Inductors can do it, too.

Magluvin

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Re: Lenzless resonant transformer
« Reply #102 on: March 01, 2014, 01:34:04 AM »
If this large 3rd coil was physically rotated 90º so it would be encompassing both the primary and the secondary windings, then you would be able to detect the induction caused by the leakage flux spilling out of the core.  The more current flows in secondary, the more voltage is induced in this 3rd winding. 
It is just a neat trick to detect how much flux leaks out of a transformer's core.  It has a large educational value.

P.S.
As always, the even number of layers of back&forth winding rule designed for pitch-current nullification, applies to all windings.

I think a better way to measure the field leakage of a toroid core in operation would be to us a coil that I added to the pic you posted above.  It should not be in direct physical contact with the toroid windings or core.   

Mags

dieter

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Re: Lenzless resonant transformer
« Reply #103 on: March 01, 2014, 01:52:05 AM »
So, Verpies, let me get this straight, the scope shot says "OU"?

verpies

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Re: Lenzless resonant transformer
« Reply #104 on: March 01, 2014, 10:26:34 AM »
I think a better way to measure the field leakage of a toroid core in operation would be to us a coil that I added to the pic you posted above.  It should not be in direct physical contact with the toroid windings or core.   
Yes, this will work. too and it will avoid capacitive coupling.

Alternatively, such leakage detecting coil can be placed inside the toroid's hole (please make a pic of that configuration, too, for completeness and for the future).