Kapanadze Cousin - DALLY FREE ENERGY

[SeaMonkey]

Well, if people won't listen to my advice, which I have given about these circuits several times before, maybe when itsu and void are telling you the same things (use multiple poly film caps of the same value in parallel to make up the total cap value needed, use short heavy direct symmetrical wiring paths for all the tank circuitry (mosfet drain, capacitor bank, coil), apply ample gate drive voltage, clean signal to gate, have the Gate circuitry tight and symmetrical) folks will take _their_ advice and your heating problems will go away. I'm sure you have all seen my videos where I run essentially the same circuit, using the same P260 mosfets, for long times at high power without any overheating problems in the circuit. The loads I run can overheat since they are getting so much power throughput, but the driver circuit itself does not run excessively hot, if I use the proper capacitors. The Sprague orange drops are very good and I recommend them, however I have been able to fail a couple of them from overvolting, usually in the receiver part of the complete apparatus. Select poly film caps that are voltage rated at 10 to 20 times your supply voltage! Build up your capacitance value by using several lower-value, equal, caps in parallel.
I like to use 10 caps of 1/10 the desired final capacitance value, just because it is easy to do the math. For example if you need 100 nF, use 10 ea. 10 nF in parallel, all the same, all with at least 250 V rating.
Part of the mosfet-heating problem is reflected power from the tank circuit. This is the same problem that CBers and Hams encounter with antenna matching. If your SWR is high you will have lots of power reflected back into the output transistors and they will overheat. In these present circuits "Low SWR" translates into symmetrical output wiring, few interconnects, short and heavy conductors for the tank itself.

Your advice is good.

Experimenters who are accustomed to working with small
signal and power size bipolar transistors (Current Controlled)
where a Base Resistor is nearly always required in order to
limit Base Current, find the transition to using MOSFETs
a little bit confusing.

Unfortunately, many of the experimenter schematic diagrams
which circulate the forums show resistors in the Gate Drive
portion of the circuit which have values of resistance far too
high thus causing switching and overheating problems.

Many experimenters finally come to the realization that the
MOSFET requires from 10 Volts to 15 Volts of signal drive at
the Gate to fully turn it ON after a small pile have been destroyed
due to overheating.

And it takes quite some time to become aware of the other
failure mechanisms of the MOSFET and how to incorporate
features into their circuits which will prevent such failures.

Unfortunately, many experimenters who are attempting to
use MOSFETs need to do considerably more study of the devices
in order to be able to make use of them intelligently and in
such a way that stable, reliable performance is the result.

As you are well aware, once an experimenter learns a certain
way of "doing things" and accepts that as being the "right way"
then there will be resistance to any who attempt to explain why
what they're doing is really wrong.  Resistance to Change still
exists after several thousands of years of technical progress and
advancement.  It may in fact be stronger now than ever before.

The MOSFET (Near bottom of page=Why MOSFETs Fail)

MOSFET as a switch.

MOSFET getting hot.

Rome wasn't built in a day.  At the rate we're going with the
quest for the ever elusive Overunity and Excess Energy we
may never "git 'er dun."

[Hoppy]

  Hoppy:
  Ok thanks for checking it out for me, and confirming that I have it right, as shown.

   This Mazilli circuit is basically USELESS, as is. It can only be run for a few seconds at a time, without overheating. That's why I don't recommend it to anyone. I tried it with two 12volt batteries in series, at 24 volts, and blew both of the IRFN260P fets, instantly. So, even though my batteries are old, this circuit could not handle that current, from basically dead batteries.  It doesn't matter if I just have a 25 watt bulb connected, or 7 100 watt bulbs, the overheating is present at any load.

Nick,

I did warn you about running it at 24V with the 12V zeners you have fitted! Follow all of the advice you have been given and you will succeed. Start afresh by completely re-wiring your components using the shortest possible heavy interconnections and use multiple caps in parallel (to minimise ESR) as TK advises. Power-up with a good and higher capacity 12V battery and only go to 24V when your happy that your mosfets are not overheating.

[NickZ]

  Hoppy:
  I am following ALL the advice, even though not one of you has had any success to show for it. This means a self runner, which can be run 24/7, on 24v, (or NO battery), without over- heating issues.

  The schematic posted above, is showing that this same circuit can be run from 12v to 36v.  Using the SAME exact components that I have.
So, which is the part that I'm not following?

  The two fets were blown last year, not now, and have been replaced by the same exact fets. This while running on two dead 12v batteries. Imagine what two new 12v batteries would do. Heating issues are NOT resolved, nor have any of the suggestions made, make any difference on my circuit, as yet.
  I'm still waiting for my 18v zeners, to see IF there is any reduction in the overheating issue with the fets. Somehow, as MenofFather mentioned, fets are heating still even with the zeners that he used, in place.
   This circuit is an induction heater circuit, using 12v, 0.5 or 0.6 watt zeners for gate protection, as shown in the diagram. Neither the zeners, nor any of the 4 resistors, nor any of the tuning caps used are getting hot, at all. Nor is the feed back circuit getting hot or even warm NOW, as well. But, the Fets mounted on heat-sinks, with fans running would go up in smoke in a minute or two.
  I will however include bigger motherboard type of heat-sinks, and fans, in my next Akula build. As he has them on there, for a reason.

[Hoppy]

  Hoppy:
  I am following ALL the advice, even though not one of you has had any success to show for it. This means a self runner, which can be run 24/7, on 24v, (or NO battery), without over- heating issues.

  The schematic posted above, is showing that this same circuit can be run from 12v to 36v.  Using the SAME exact components that I have.
So, which is the part that I'm not following?

  The two fets were blown last year, not now, and have been replaced by the same exact fets. This while running on two dead 12v batteries. Imagine what two new 12v batteries would do. Heating issues are NOT resolved, nor have any of the suggestions made, make any difference on my circuit, as yet.
  I'm still waiting for my 18v zeners, to see IF there is any reduction in the overheating issue with the fets. Somehow, as MenofFather mentioned, fets are heating still even with the zeners that he used, in place.
   This circuit is an induction heater circuit, using 12v, 0.5 or 0.6 watt zeners for gate protection, as shown in the diagram. Neither the zeners, nor any of the 4 resistors, nor any of the tuning caps used are getting hot, at all. Nor is the feed back circuit getting hot or even warm NOW, as well. But, the Fets mounted on heat-sinks, with fans running would go up in smoke in a minute or two.
  I will however include bigger motherboard type of heat-sinks, and fans, in my next Akula build. As he has them on there, for a reason.

Nick,

With respect, I'm not aware that you have followed all of the advice. You have yet to report that you have procured a 'healthy' battery with increased capacity to avoid excessive volt drop when powering your Mazilli load. I can assure you that its quite possible to run a properly constructed Mazilli at 24V or higher. The higher rated zeners are not going to solve your heating problem even with a 12V supply rail if the battery is inadequate and cannot supply sufficient voltage to the mosfet gates whilst under load.

[magpwr]

  Hoppy:
  I am following ALL the advice, even though not one of you has had any success to show for it. This means a self runner, which can be run 24/7, on 24v, (or NO battery), without over- heating issues.

  The schematic posted above, is showing that this same circuit can be run from 12v to 36v.  Using the SAME exact components that I have.
So, which is the part that I'm not following?

  The two fets were blown last year, not now, and have been replaced by the same exact fets. This while running on two dead 12v batteries. Imagine what two new 12v batteries would do. Heating issues are NOT resolved, nor have any of the suggestions made, make any difference on my circuit, as yet.
  I'm still waiting for my 18v zeners, to see IF there is any reduction in the overheating issue with the fets. Somehow, as MenofFather mentioned, fets are heating still even with the zeners that he used, in place.
   This circuit is an induction heater circuit, using 12v, 0.5 or 0.6 watt zeners for gate protection, as shown in the diagram. Neither the zeners, nor any of the 4 resistors, nor any of the tuning caps used are getting hot, at all. Nor is the feed back circuit getting hot or even warm NOW, as well. But, the Fets mounted on heat-sinks, with fans running would go up in smoke in a minute or two.
  I will however include bigger motherboard type of heat-sinks, and fans, in my next Akula build. As he has them on there, for a reason.

Dear Nickz,

I just took a look at your youtube video -http://www.youtube.com/watch?v=F6OX3E0AKB0 once more.

Please don't get me wrong if i say your heatsink don't comes with fins to dissipate heat.At the moment it is just a block of aluminium on the bottom which means this is good enough for short testing only.
If you get a proper heat-sink with fins which can be shared by 2 mosfet provided if there is think insulation between mosfet and heatsink and a mini 12v fan on heatsink it will assist to remove heat efficiently.

There is normally rating on heatsink on how many watt of power in heat can it dissipate efficiently.

My advise will help you save your mosfets$$$.

If you build mazilli like i did using some ultra fast components as shown in video with short-circuit test at output and show my mosfet don't get destroyed at all base on this setup with 12volt battery.
"This setup will save you money and prevent a downtime."

Ultimate Mazzilli circuit v1.0 (Short Circuit Proof tested)
http://www.youtube.com/watch?v=0u6gAUPlnTQ

If i were go for 24volts i will just unscrew connectors to mosfet and put in a IGBT which will surely run nicely on 18volts...20volts present at it's gate via pull up resistor.Tvs or zener diodes won't be required for igbt gates.