Kapanadze Cousin - DALLY FREE ENERGY

[AlienGrey]

The over heating problem.

If we cast our minds back a year or two I and a few others also mentioned over heating to an extent to melt the PVC tube, with only small loads, I think we later found the circuit made a good RF crucible heating furnace .

If I recall T1000 mentioned there could be a problem with some so called copper wire Iike cheap electrical trunking cable with impurities like iron and oxygen used in its manufacture.

It is possible to obtain wire used in the Audio industry which is claimed to be pure copper, however, this type of cable is 4 or 5 times dearer than fine multi strand cabinet wire battery cable.

However Copper or Aluminium is still metal.

Any one fancy winding a layered copper tube version?

Allen

[NickZ]

   As I look for the cause of the kaotic mode, I find that it happens only when the one mosfet goes into saturation, at 200 volts or above that voltage. Below that there is only little heating of that fet. The other fet has lower peaks and does not go into the same kaotic mode at the same time, or as easily.
  On the other hand, the TL494 and driver circuits are working great now. No problem, or glitches there.

   I had made a video last night, showing the effect, but the profile setting was on my camara so the video looks wrong, like sideways, so I didn't uploaded to youtube. I'll try to make a better video later tonight. But my camera turns off if I get too close to the HV.
  The main thing right now is still to get these snubbers working properly, or I'll keep blowing more FETs.  I have to get the peaks to 200v but not above that point. Or the effect won't happen. As it won't kick into that kaotic mode, at lower voltages.
And, Hoppy from what I can see so far, it's in that special kaotic mode where the magic is to be found. And which is caused by the Kacher's interaction, and not just a failing Fet..

[Hoppy]

   As I look for the cause of the kaotic mode, I find that it happens only when the one mosfet goes into saturation, at 200 volts or above that voltage. Below that there is only little heating of that fet. The other fet has lower peaks and does not go into the same kaotic mode at the same time, or as easily.
 

This is an interesting observation in that if we assume that the 'hot' mosfet has avalanched, then it is in effect acting as a zener diode and conducting a high current whilst clamping the voltage at level governed by the heat level of the mosfet die. If this condition is critical for the 'effect' to occur, then it suggests that a constant or pulsed DC bias current is needed in the yoke primary winding. Another thought is whether a pulsed avalanche condition is feeding very sharp unipolar pulses into the yoke primary winding, a condition created by Tesla with his spark gapped devices.

[AlienGrey]

Nick
I think you need to go back a bit, try disengaging the Katcher and loading the grenade output with a small build 40w something like that and monitoring the waveform from the yoke output with a winding of a toroid or direct and monitoring the two drain wave forms, you could video them. But you need to see whats going on with your setup.
Allen

[itsu]

Found this PDF:  http://www.semtech.com/images/datasheet/transient_voltage_protection_of_mosfets.pdf

It gives some usefull info on how to protect a MOSFET drain and gate by using a TVS.

Guess for our setup (IRFP260 = 200V) we can use STMICROELECTRONICS SM15T82AY DIODEs.
It has a working Voltage (Vrwm) of 70V  (max in our case would be 2x 24 =  48V)
and a clamping voltage of 146V which is way below the 200V


•  Breakdown Voltage Max:   86V 
•  Breakdown Voltage Min:   77.8V 
•  Clamping Voltage Vc Max:   146V 
•  Diode Case Style:   DO-214AB 
•  No. of Pins:   2 
•  Packaging:   Cut Tape 
•  Peak Pulse Current Ippm:   69A 
•  Power Dissipation Pd:   1.5kW 
•  Reverse Stand-Off Voltage Vrwm:   70V 
•  SVHC:   No SVHC (16-Jun-2014) 
•  TVS Polarity: unidirectional

Itsu