Reactive power - Reactive Generator research from GotoLuc - discussion thread

[Dave45]

Gentlemen its a pleasure watching you work, your teaching the rest of us with limited experience,
Thank you very much.

dave

You may consider this circuit by Mr Lindman, some of you have probably already seen it but thought I would bring it to your attention if you havent.

[Farmhand]

That is because the system is not tuned precisely under load.
 
Itsu is using two identical caps and loosely coupled coils but the current flowing in the secondary winding under load, effectively DECREASES the inductance of the primary winding (due to Lenz law, reflected impedance, etc...)

If Itsu had searched for the precise primary LC resonance frequency (f_P) under load  - while the secondary winding was connected only to the output bulb (no cap), then he would find that f_P is higher with a loaded secondary winding than with an unloaded or open secondary winding.

Finally, if he tuned* the secondary LC tank's resonance frequency (f_S) to be equal to the primary resonance frequency (f_P) under load, according to the procedure just outlined above, then the whole system would behave more perfectly (like in the first video).


P.S.
* e.g.: by decreasing the series capacitance in the secondary LC tank.

The fact still remains that all the current supplying the primary to power the load (via transformation) is delivered through the globe in the primary circuit, and if the load is using most power at full resonance in the secondary circuit the maximum current should flow through the bulb when maximum power is dissipated in the secondary load ( assuming an ideal supply ). Or to be more correct when the maximum power is dissipated in the secondary load the most power will be delivered by the supply via the primary. Not much else matters in the big scheme of things.

Cheers

The insinuation by some is that when the secondary load is dissipating the most power the supply is outputting the least power or the (primary is consuming the least power). Completely illogical.

..

[itsu]

Ok, i toke a quick shot at trying to get a flatline response on the parallel (left) bulb during resonance by manipulating the cores inside the coils.
This should also manipulate the inductance like decreasing the capacitance as mentioned by verpies, but its not working as expected.
I get a async resonance response when doing so and still the left bulb has some signal during resonance allthought i can bring the overall
resonance signal down meaning that the left bulb won't light anymore, but the cost is that also to right bulb is less intense.

So i leave it as it is.


I got more questions about the input and output power when in resonance.
The next 3 pictures show:

1 the output bulb (right) power at resonance            (2x 122mW  = 244mW), (Ch1 RMS x Ch4 RMS)
2 the input power of the whole system at resonance  (2x 147mW  = 294mW), (Ch3 RMS x Ch4 RMS)
3 the input bulb (left) power at resonance                (2x 13.5mW =  27mW). (Ch2 RMS x Ch4 RMS)

(i use 2x as my current probe is at the 2mA/mV setting).

So we have still 23mW unaccounted for, but that will be found in some thermal losses i guess.

Regards Itsu

[TinselKoala]

If you have a phase shift between voltage and current... which apparently you do... is it still legitimate simply to multiply RMS voltage by RMS current to get a power figure?

[gyulasun]

Ok, i toke a quick shot at trying to get a flatline response on the parallel (left) bulb during resonance by manipulating the cores inside the coils.
This should also manipulate the inductance like decreasing the capacitance as mentioned by verpies, but its not working as expected.
I get a async resonance response when doing so and still the left bulb has some signal during resonance allthought i can bring the overall
resonance signal down meaning that the left bulb won't light anymore, but the cost is that also to right bulb is less intense.

So i leave it as it is.

...

Hi Itsu,

You are surely familiar with the coupling coefficient, k, between coils in mutual induction, two coils can be under,  critical or over coupled, for those wishing to learn about these, here is a link:
http://www.crystal-radio.eu/enkoppelfactor.htm

When you tried to move (manipulate) the ferrite cores in your coils, both the coupling and the inductance of each coil changed at the same time,  a better method is to change the distance between the coils and fine tune the coils for a voltage peak each time. To do this in your case, no ferrite cores should overlap between your two coils and individual cores should be used for each coil to do the fine tuning which is needed because changing the distance detunes both coils and it is not enough to change the generator frequency for compensating this detuning: you would need to fine tune the coils by their cores at each new distance (ideally, in fact you would need a trimmer capacitor in parallel for each coil too because moving the cores can also change the coupling albeit the coils are just not moved).

Of course, such tuning can be a tedious process, the final goal would be to achive the critical coupling which would insure maximum power transfer with a single peak response (notice that you also get a single peak response when the coils are undercoupled). 

Regarding the flat line response of the left hand side bulb, you can achieve that by slightly reducing your generator output level...  and I say this because in your present setup the maximum current which is drawn and governed by the right hand side bulb at resonance is just able to make the left hand side bulb to slightly glow. (The voltage drop across this left hand side bulb increases at resonance because the resistance of the bulb increases as the small glow is starting (typical nonlinear resistance increase/response of the filament to heat.) 

I am not saying you should undertake a tedious fine tuning process to achieve the max power transfer with critical coupling, (that would involve separating the two coils) you have already done an excellent series of tests on this.

Greetings, Gyula