Kapanadze Cousin - DALLY FREE ENERGY

[NickZ]

  Well, I hope that there are still some of us working on something...here.

  I've had some hang-ups with my system, so I've been trying to figure out what to do about it. Since the new 24v 10ah PS won't drive the Mazilli/yoke/grenade circuits. But, the circuits will still run on 12v 7ah battery, even though the new yoke is wound for 24v.
The circuit seem to be drawing way too much current, which I can tell by the spark seen when connecting the circuit to the battery terminals. And, this is probably why the PS kicks off, from the over current that is being drawn. I've removed and tested the two fets, which appear to be ok. But, maybe something happens to them under load.
  Anyways, that's what I've been up to, as well as getting a feel for what my scope is showing me.
  I'm still looking to buy a commercial push-pull TL494 driver, if I can find one. As well as an adjustable Tesla coil driver with frequency controls and duty cycle controls.
  Now my camera won't work, so I'm back to using the cell phone for videos, for now. I make some soon, once I figure out what to do about my device, and it's overheating and over-current loading problem. 

[gyulasun]

Hi Nick,

Just an idea to reduce the initial high current draw from your new 24V power supply when you connect the Mazilli/yoke/grenade circuit. You could use a choke coil right in series with the positive output of the 24V PS, this would work just against a sudden high current draw if its inductance is high enough (some hundred milliHenry and higher). Such choke coil should have a low DC resistance with a relatively high number of turns, this calls for thick wire and an open magnetic circuit (the latter is for preventing core saturation due to the DC current).
I guess you do not readily have such choke coil in your drawer so you could make such on stacked ferrit rods or on a laminated I core with a cross section of some square_cm, (I core from a microwave oven transformer) using at least 1mm OD enameled copper wire, winding some hundred turns at least.

Alhough choke coils are used at the AC input of computer or monitor or TV set power supplies too but usually their inductance is but a few mH or even less and they are also so called common mode chokes (google for it if not known).

If you do not feel like winding a choke coil (it involves sacrificing precious thick copper wire for sure), then a simpler test to try would be to use a high wattage resistor of 24V/10A= 2.4 Ohm or a bit higher: this would limit the output current to just 10 Amper or below it when you connect such resistor in series with one of the DC outputs of the 24V PS so that the overcurrent protection of the 24V PS would not trip when you connect your circuits. And if your circuits are able to start via the series 2.4 Ohm (or with a bit higher, say 2.8 or 3 Ohm, high wattage), then you could try shorting the resistor to see whether the circuits could continue working then.  Be careful to avoid overheating the resistor if the circuits do start up via that resistor and your current draw will happen to be say 8 Amper: heat dissipation in the resistor would be 8A*8A*2.4 Ohm=154 Watt at least.
In case you do not have a high wattage resistor at hand either, maybe a  hair dryer of 1kW+ or an electric iron (1.5kW) or an electric cooker could be tested in series with your PS too but they have at least 11-12 Ohm series resistance for the 110V 1kW+  types, so they would limit the output current to 1-2 Amper if used alone (paralleling them do help of course).

Gyula

[NickZ]

  Gyula:
  Thanks for your advice.
   I have not one but two chokes going to the center tap of the Mazilli (image below). I've had as many as three or even four chokes, on at the same time. But, still too much heating of the fets. No other components heat up, only the fets which become untouchable in about 15 seconds running time, even when running a single 100w bulb, and more so on higher loads.
So, I'm working on this, I've changed fets, resistors, diodes, UV diodes, etz... but, still overheating. The fets are the IRFP260N, 480ohm resistors, 10k resistors, 18v zener diodes, UF 306 cross-over diodes. The second image below is what the circuit looked like a while back, but if needed I can take a newer picture of it.
  I'll get it, when I do, the PS will probably be able to run both the Mazilli and the Kacher circuits ok. But this PS is known for NOT providing the 10amp output, and also dropping the voltage when running a large load. So, if it won't cut it,  I'll have to buy another new 12v battery to have two of them providing for the 24v input.
  Some times these issues can have a positive result, in time, at least I hope so.

  Hoppy: You've mentioned previously something about having bought some of the commercial induction heater driver circuits. Did you ever get a chance try them on the yoke/grenade set up?

[TinselKoala]

Nick, what are the part numbers of the diodes you are using in the Mazilli?

[Hoppy]

  Hoppy: You've mentioned previously something about having bought some of the commercial induction heater driver circuits. Did you ever get a chance try them on the yoke/grenade set up?

Nick,

Out of interest, I purchased the PWM module here, which is the same one as you linked to a few pages back. It is designed to drive a Tesla coil setup and does drive the yoke / grenade. However, although it has some elaborate protection circuitry, I do not consider it suitable for this type of project as its all to easy to damage the module. I had to replace the IGBT because although I saw the HV warning LED illuminate and disconnected the power supply, It was too late and the damage had already been done. Replacing the IGBT was easy enough for me but might not be for others as the module is a very compact with most components surface mounted. As I've commented before, IMO its better for a beginner in electronics to develop the skills and knowledge to DIY build a PWM board for this type of experimental project.