Kapanadze Cousin - DALLY FREE ENERGY

[itsu]

Aaaaaa, get rid of it!   

Okay, working on it, but it looks like these pesky little spikes slip through anyhow :-)

Did it worsen the offâ†'on transition of the MOSFET much ?

i think it even improved it, see the picture above, almost symmetrical 200V pulse.

I'll watch it as soon as YouTube resumes working.

Ok, guess these spikes/ringing i see is from the inductance of the toroid, and not from the resistor.

I blew up a third MOSFET so am down to the last one, guess they are not up to all that abuse.

regards Itsu

[verpies]

@Itsu
I just managed to watch your latest video.

The ringing after the drain pulse is due to that 1kΩ and 1nF "spike remover" which forms an LC tank with the primary inductance of the T1 and the eventual inductance of the CSR.
A 250V transil would be more effective in suppressing these oscillations, but they can be ignored for now, if they do not interfere/damage anything. 

A non-inductive CSR can be quickly made out of straight piece of Nichrome wire squeezed between two small brass bolts. 
The Nichrome wire can be obtained from the heating element of a broken iron (for ironing clothes) or any other heating element (household or automotive).

The attached snapshot shows the portion of the waveform that we are interested in (the rest we ignore).
The slope (di/dt) of the almost vertical red trace tells us the inductance of the primary.  L=V*dt/di
Where the V is the power supply voltage (e.g. +200VDC) and dt is the current rise time (e.g. 10ns) and di is the current change (e.g. 2A) occuring during the rise time.
I wish the horizontal scale of the scope was set to less ns/div so I could see that slope better.

As it is now, I do not see any signs of saturation at this scale (unless it happens very early).
Thus the natural course of action is to wind more windings on that core to artificially increase the inductance for testing.
(2 equal layers of course, both CW but one of them in opposite direction along the outer circumference )

[Hoppy]

Okay, working on it, but it looks like these pesky little spikes slip through anyhow :-)


i think it even improved it, see the picture above, almost symmetrical 200V pulse.



Ok, guess these spikes/ringing i see is from the inductance of the toroid, and not from the resistor.

I blew up a third MOSFET so am down to the last one, guess they are not up to all that abuse.

regards Itsu

Itsu,

Check your gate voltage is at least 12V, preferably a bit higher. I go for 14v to 15V when using mosfet chip drivers. The two transistor driver shown on a couple of the schematics will not provide enough gate voltage if supplied from a 12V rail.

I've had little success so far in raising the voltage across L4 using the Dally spec coil.

Regards
Hoppy

[verpies]

Check your gate voltage is at least 12V, preferably a bit higher. I go for 14v to 15V when using MOSFET chip drivers.

I agree. The closer the supply voltage of the gate chipdriver to the maximum rating of the MOSFET's gate voltage - the better.
I did not mention it because I did not want to complicate Itsu's design with yet another supply voltage (e.g. 15VDC) and deviate from Dally's design.

Of course it never occurred to me that Itsu might not supply the gate chipdriver from the main 12VDC power supply, since the original gate driver, made out of Q3 and Q4 transistors, was supplied from this 12VDC supply. 
Supplying the gate chipdriver from the 5VDC supply of the TTL Logic (U2 , U3) would be a huge mistake! 
That's what we get for working without a decent up-to-date schematic.

Since the TL494 works well up to 40VDC and the TTL Logic (NAND gates in U2 & U3) have their own separate 5V voltage regulators, then the main 12VDC power supply can be increased to 15VDC (or maybe even to 20VDC). 

Also, some of the crappy gate chipdrivers treat any input below half of their supply voltage, as low logic level, which makes their inputs incompatible with TTL outputs.
I did not check if Itsu's driver belongs to that category.

[d3x0r]

@Verpies; re Itsu's back ringing, the toroid is unloaded, and the other winding open, the field generated there is collapsing back into the primary more than the resistor and other inductances are playing a factor....


is there a huge difference between FJL4315OTU-ND and the KT926?

I have a tunable 50ns-anything higher pulse from the logic chips, but that translates into an on time of 2us for the FJL4315... I've tried changing the cap and resistor on the gate, but it's always the same...

Last night, I was playing with the tuning of the TL494 oscillator, and put a large resistor[from high voltage source to ground] (100k) started with smaller ones (4.7k) but nearly burned it up when I got the primary tuned... the load matters a lot in tuning the primary; but I had a very nice square wave which yields the most power, but it's wasn't best for high voltage... power in that I was able to keep a voltage in the caps above 0 with the resistor in place... so I tuned it so I had the most voltage in the neon caps that I could with a good load on it... this setting is very bad for charging the cap from 0... it gets about 30% and then stalls, I have to slow down the frequency, and as it goes up, increase the frequency to get best voltage buildup.  So once I was able to maintain that high voltage with a load, I connected it to the nanopulser, and was able to see quite well the voltage between collector and emiiter, go from 150 to 0 and recover... but I had left my 100k ohm resistor in-line, so I wasn't getting a good signal through the toroid.  Removing the resistor, or replacing with a lower value, the voltage drain is much too much with 2us (2000+ns)... and a few times I drained it past the point it would want to fill the cap back up...


----
Well since noone posted, I can continue...


I put a circuit similar to the high current driver on the TL949, and got the pulse down to 1 microsecond maybe less... I tuned my nanopulser down to about 4.2khz (when I'm at that, my toroid starts ringing just ever so slightly); It's a balancing act though... if I go too high in frequency, the high voltage invert isn't quite enough to keep it supplied, and if it falls below say 60% voltage, it's not very good at recovering... if I go all the way to zero, I can turn the nanopulser down , turn the frequency of the TL949 down, get a square wave on the collector/emitter of a E13009, and as the voltage charges, have to keep increasing the frequency to keep the square wave... I can maintain almost 200V, with nanopulser, and get about 48 volts, and maybe 30ma draw on L4; input is 12.7V at about 0.60A... so it lookw like a net increase, pretty sure I have my TR2 backwards though.