Kapanadze Cousin - DALLY FREE ENERGY

[verpies]

I thought that Verpies meant this voltage to be 48v. But may be I am wrong.

You are not wrong and neither is Itsu.
It should be 48V in reference to ground.

So except for the long wires (especially the gate wires) i don't see anything obviously wrong with your setup.

Yes, and the C3 and C4 capacitors need not be rated 160V.  Mere 50V would be enough and lower voltage caps have better ESR, too.


I agree with Itsu about the the MOSFETs' wire layout.  Also, I hope you are using this schematic to connect the W1 windings to C3, C4, D3, D4, GND and V_CC.  The EMI chokes L1, L2, L3 before the filter caps are a very good idea, too.
I am pretty sure that if you had copied  Itsu's transistor and driver connections layout, then you'd be rid of these spikes.

[Void]

Hi Void
Yes I guess there is not any problem for little ringing considering a self running operation. It is just a matter of self satisfaction

Hi Jeg. Sure. Also it sure can't hurt to get the PWM driver circuit working really clean and stable and efficient.
As others have commented, it is in the very least a good learning experience.

[starcruiser]

@ITSU,

Could you try and normalize as Verpies suggests and then reduce the spectrum width to 5Mhz, want to see what the response is for 1.2mhz to 3Mhz, i.e. the Tesla coil sympathetic response. Also reduce it again to see what the coil shows for the 0hz to 50Khz BW sweep.

Just wanting to see what your setup shows to see if the core will attenuate the Tesla or nano pulse frequencies (I think it should) versus the lower frequency switching setup (28Khz).

[itsu]

I have not watched or analyzed your methodology yet, but the most common thing that can go wrong with these measurement is distortion of the tracking generator's output due to impedance mismatches and reflections.  The solution is to put a circulator or attenuator at the generator's output in order to isolate it from a misbehaving load.
Not normalizing the spectrum analyzer when the output cables are connected directly to the input cables (without the DUT), is another common rookie mistake (if an isolating attenuator is used - it should remain in place and participate in the normalization).

Applying DC to other transformer windings through a good choke, is another test that can be performed to see how the transformer's core responds at various magnetic fluxes.  Flux generated by such DC, has a different direction than the flux from external permanent magnets.

@All
Notice, how complex the frequency response of a simple yoke transformer is.
I expect the frequency response of the grenade coil to be even more complicated.

It is no wonder that it is so difficult to replicate with such unknown complexities.

If one of the "successful" Russian friends gave us a plots like this of their yoke and grenade - we could replicate this device in weeks.

I did use "normalize" to flatten the response when testing the connecting leads which in this case also includes the 3 turn in- and output coils.
I do realize that when removing the output 3 turn coil and connecting it to the primary under test (put) it could invalidate this "normalization".
I just don't see any other way to examine this primary.

I did not use a 10dB attenuator in the TG lead, so i redid the same test now with one.
I cranked up the TG output from -10dBm to 0dBm to compensate.

The below screenshot shows the result which is similar as the earlier one.

Itsu

[itsu]

@ITSU,

Could you try and normalize as Verpies suggests and then reduce the spectrum width to 5Mhz, want to see what the response is for 1.2mhz to 3Mhz, i.e. the Tesla coil sympathetic response. Also reduce it again to see what the coil shows for the 0hz to 50Khz BW sweep.

Just wanting to see what your setup shows to see if the core will attenuate the Tesla or nano pulse frequencies (I think it should) versus the lower frequency switching setup (28Khz).

Hi Star,

as mentioned above, i did use "normalize" and now added a 10dB attenuator in the TG lead to compensate for any impedance mismatches.

The first screenshot show a 0Hz - 5Mhz (really 9KHz - 5MHz) spectrum width  and the second one a 0Hz - 50KHz (really 9Khz - 50KHz) spectrum width.
I had to reduce the bandwidth (RBW) for the 2th situation from 30KHz to 1Khz to have some decend response.
Notice also that the 2th screenshot is very close to the spectrum analyzer start limit (9KHz), so these fluctuating lines at the start are not stable and are really fluctuating.

Itsu