Kapanadze Cousin - DALLY FREE ENERGY

[Vortex1]

Vortex1,

Hmmm,  obviously there seems to be a flaw in my understanding of toroid cores.
I thought they always are made of ferrite and therefor are suitable for higher then 50Hz frequencies.
Apparently not,  thanks.

Now i understand the reasoning from Hoppy.

So need to know if the generator needs to run on 50/100Hz or at 4.6Khz, then we either can use the route suggested by Hoppy (commercial toroid 50Hz), or we need to build one on ferrite suitable for 4.6Khz.

But the fact that my toroid get very hot in seconds when running on 220V 50Hz still points to a defect in it.


Black_Bird,  Vortex1,

Concerning the zeners; so that's clear then why they became hot :-)  i will try higher voltage rated zeners across each MOSFET if still needed after using a good toroid.

Thanks for your comments,    Regards Itsu

Yes, many toroidal cores for mains 50/60 use are tapewound  alloys utilizing grain oriented steel for low eddy current loss.

If your transformer runs hot off the mains, it could be a short as you say, or it could have been designed for lower line voltage like 208 and is saturating. Does it have an input rating tag? You can test it by putting a resistor ( one ohm ) in series with the core and running it up slowly on a Variac while observing the current waveform across the one ohm. Also observe the secondary voltage, and see that it is a nice sine wave. If it is extremely distorted or does not reflect the rated turns ratio, it is probably shorted or saturating very early.

You are correct that 4.6 kHz (assuming a ferrite core) should be the operating frequency, not 50 or 60 Hz.

Best of luck.

[T-1000]

Video to be seen here: http://www.youtube.com/watch?v=YZQT8mN0AtE

Thanks for your comments,  regards Itsu.

Thanks for the try itsu.
The originial circuit http://img1.liveinternet.ru/images/attach/c/6/91/496/91496155_large_TL494Generator.JPG got E13009 NPN transistors on output and I suspect there is sine wave on push-pull output. Also you have MOSFETs on output and in this case you need to make sure they are not half-open when TL generator is not connected. Also when the generator is connected you may have race condition problem with flipping over between then and if that is the case, you may get lots of amps consumed. Also there is lots of amps consumed if your primary on toroid has too low impedance.

The main inverter circuit is quite standard there and the main process is making realtionship between 2 secondaries when 1kV 1nS sharp triangle pulse generator is working in sync comming from inverter TL circuit:
http://img0.liveinternet.ru/images/attach/c/6/91/488/91488162_large_Dally.JPG

The list of Russian parts:
The SN7400 is analog for KR155LA3 - http://partnumber.ru/product_info.php/products_id/15080
КÐ"203 - http://radioelectronic.ru/diody-kd203/ (max back voltage 600V, max frequency 1kHz, max amperage 10A)
КТ926 - http://lampilich.narod.ru/tr/b_big/kt926.html , http://www.betatvcom.dn.ua/komplekt/pdf/active_comp/tranzistorSVH/KT.pdf (NPN, max C-E impulse voltage 200V, DC=150V, Imax impulse = 15A, Imax DC=15A, h21e = 10-60,Pmax = 60W, fmax = >51Mhz)

P.S. You need to see if you got 2 primaries right. They should go into opposite winding directions. Otherwise it will be plain DC short circuit with same polarity when one goes off and second goes on.

Cheers!

[verpies]

@Itsu
Here are several of my observations regarding your latest video (I watched only half of it):

1) You probably already know that transformers do not transform DC.
A transformer "transforms" only when the current changes through its primary winding.  However your drain current waveforms show significant amount of their time spent along the flat top of the pulses (flat means DC!). 
During those "flat tops" you are only burning energy in resistances!  None of that electrical energy is going into changing the transformer's magnetic field, thus none of it is getting transformed and none of it appears at the secondary winding (output).
You are way way past point D in the yellow trace I_L of my Reply #29 and you should not be much past point C (or even better B). 
You must decrease your pulse width or increase your frequency or increase the inductance of your primary windings.

2) The determination of the proper "phasing" of the push-pull primary windings (yellow  & blue) can be done like that:  Apply 230V AC to the red secondary winding of your transformer (this would be the primary winding if operated as intended originally, like a step-down transformer). Next, connect your two yellow and blue primaries in series (originally intended as 10V AC secondaries) and measure them with an AC voltmeter.  If your resulting voltage is double that (20V AC), then you have them connected correctly.  If not - break the red vinyl tape and make an alternate series connection by switching one yellow wire for another yellow wire (don't switch both yellow and blue wires at the same time!).

3) I did not realize that sources of your MOSFETs are connected to ground.  Since they apparently are, make sure that the voltage between the MOSFET sources and the Vcc, is pure DC.  Vcc is the point where the two primary transformer windings join together - I think you have a red vinyl tape there over yellow and blue wires joined together.  If it is not pure DC then bypass these points with low-ESR capacitors.  Also since your sources are connected to ground, then put your current sensing resistors on the drains of your MOSFETs in order not to perturb your source-to-gate voltages, and measure the drain currents across these resistors.

4) The Zener diodes should conduct only during the "dead time".  Putting  a scope probe across a Zener diode will tell you when the voltage across it is approaching its Zener voltage.

5) The cores of commercial toroidal transformers used for halogen lighting are wound using ~0.5mm thick silicon steel tape in a tight spiral pattern.  This tape is conductive and will develop significant eddy currents at high frequencies.  What is "high" depends on the thickness of that tape and insulation between the layers of the spiral core.  A torroid is only a shape and not all toroids are made out of ferrite.  Some cores are even made out of Nanoperm tape (~0.05mm) which is not all that expensive and has fantastic permeability, high resistance and can operate up to 100s of kHz - a good alternative to ferrites at those frequencies.  But don't despair I have seen these regular silicon steel-tape transformers operate at 90kHz in an audio amplifier output stage without any problems (see the attached picture of my vintage amplifier project built with those transformers)


I'll watch the rest of your video soon.

[Hoppy]

Thanks for the try itsu.

The main inverter circuit is quite standard there and the main process is making realtionship between 2 secondaries when 1kV 1nS sharp triangle pulse generator is working in sync comming from inverter TL circuit:
http://img0.liveinternet.ru/images/attach/c/6/91/488/91488162_large_Dally.JPG


Cheers!

T-1000,

I'm confused about the above sentence. To me it reads that the inverter circuit is producing 1KV 1nS pulses. As I commented earlier, with the R & C component values shown (10K & 1uF), the frequency from the TL494 will be around 100Hz. The Dally schematic will work up to around 500Hz with the 1uF, 22K pot and 10K fixed resistor shown.

Hoppy

[Vortex1]

Hoppy is right. If that capacitor is truly 1000nF, the frequency will be low as he stated, which means a low frequency mains transformer will work fine.

Is it then the comb pulse generator (nano pulser) that is running at about 4.6 kHz repetition rate?

Verpies:

Do you have more info on your tube amp? I'm a hobbyist builder of tube amps and always wondered how well mains transformers would work as output transformers but have not had time to try it. would be very interested in your test results but do not want to derail this thread. Is your work posted anywhere?