Lenzless resonant transformer

[Jack Noskills]

capacitor in place of input bulb

[Jack Noskills]

If parallel capacitor in the primary side is removed so that only inductor is left, would bulb in primary side reflect power consumption any better ?

[verpies]

If I would use small capacitor (C1) in place of the input bulb then that should give me maximum input power the system can use at a certain frequency ? How to compute that, Q*U*U*2*frequency ?

First calculate the total reactance of the primary circuit at given frequency X_C1 + (1/X_C2 + 1/X_L).
The capacitive reactance is equal to X_C=-1/2πfC
The inductive reactance is equal to X_L=2πfL

Then use the MPTT to compute power in the primary circuit.

Finally you'll have to account for the reflected impedance of the secondary circuit, e.g. the real part of the secondary impedance (the ohmic resistance) will influence the inductance of the primary winding. The higher the mutual magnetic coupling and the lower the resistance of the secondary circuit, the lower the apparent inductance of the primary winding.  Calculating the reflected imaginary part of the secondary impedance, will put hair on your chest.

[itsu]

First some open ends from yesterday answered:

(Mind you this is now with 7nF caps instead of the 220nF caps used in the video yesterday.
I redid the same test yesterday also with 7nF caps and the results where similar as with the 220nF caps in the video, only the resonance frequencies where higher).


opening the secondary and scoping the primary LC (while injecting a signal with an extra few (7) turns) shows a more peak like
resonance (using 7nF cap) of 21.3KHz at 80V pp, while the 40Vpp frequencies are at 44 and 11KHz.

Connecting my bulb to the secondary only, removes any resonance completely, at least i see no more resonance peak.


I then rewinded my coil to have 2 complete turns on the circumference of the core, but after 1 revolution i turned back, so have now
a forth and back kind of winding (this is where the next video starts).

I redid the above tests, pointing to a somewhat similar resonance peak of around 22KHz (7nF cap prim, open end sec), while when attaching the
bulb to the secondary again, the resonance disappears!


Then i set up again the first test with this rewounded coil, meaning primary LC (7nF cap) feeding through the input bulb, and output bulb inbetween the
secondary series LC.


Hunting for resonance now reveals a total different picture as yesterday, as the primary peaks (bulb off) around 22KHZ and the secondary
peaks (output bulb dimly on) around 550KHz!!??

Further measurements include the input power (SG rms voltage * SG rms current = Math avg) when primary in resonance and secondary in resonance.
It shows that the input current around primary resonance was leading or trailing the input voltage by 90° depending on which side of the resonance we are.
But it also shows that when the secondary is in resonance, the input voltage and current are in phase, meaning a pure resistive load?

Video here:  http://www.youtube.com/watch?v=o2HzTHopA_Y&feature=youtu.be   

Questions:
why is the resonance disappearing when connecting the bulb only to the secondary (load is to much)?
why is after rewinding the coil the both resonances way off (prim. res at 22KHz / sec res. at 550KHz)?


Regards Itsu

[Jack Noskills]

You have confirmed the effect I had. I did not notice the first resonant point, most likely because it was below 1 kHz and I started sweeping from 1 kHz. Though this coil is still different from mine effect seems to be the same: second resonance point orders of magnitude higher than the first one.


What if you now remove the capacitor in primary and feed the system with 550 kHz, the second resonant frequency (could be that this changes when cap is removed) ? Primary should now effectively block all current flow and when bulb is connected to output then its effect on primary would be low.


Possibly more power now flowing on the output side compared to input side ?
Change to bigger capacitor in the output. Second resonance frequency would come down, does output power increase ?