no problem with load or output stage. centertap is not the only change, Mazzilli also adds capacitors so waveform is sinusoidal instead of square wave. all of that is fine....

A PDF explaining it better than I can

 

thanks, very interesting.
actually it also shows center tap variant and confirms startup problems, no regulation etc.
there are the diodes crossed to other transistor drain so if that transistor i on, Vgs of other is limited. may not be perfect if transistor is not fully on.

 

there are the diodes crossed to other transistor drain so if that transistor i on, Vgs of other is limited. may not be perfect if transistor is not fully on.

That is why what ever is powering these ZVS circuits need to be on and up to voltage before the ZVS is turned on.

 

Dear sir clear me one doubt in design ie. Can I bring both only MOSFET slightly out from the PCB to bigger heat sink as in inverter welding mch through flexible wires say 40mm length each sir.

 

The one I have has the mosfets mounted on the edge of the board, so any size heat sink can be used. A board like that really isn't suited for what your doing. Why not just buy a ready made ZVS? It would be up and running and cost less money in the components you have destroyed so far. If everything isn't the right values, like your homemade inductors, your fighting a losing battle, sorry. The one I have -
https://www.ebay.com/itm/1000W-ZVS-...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

 

Dear sir, yesterday night I faced a problem one of MOSFET irfp260n heating with full current .this happened when was shifting to abigger heatsink evven both MOSFET are seperated by sheild .doubt is weather MOSFET would have fail . Sir .

 

It seems like you think that a bigger heat sink will cure a bad choice of components. ALL of the components must be designed and the ones used in the drawn schematic. You can't espcially take an unknown ferrite and wind a few turns of wire around it and consider it correct for the circuit. All parts must be within the values in the circuit.

 

Dear sir . Today one event I meet in induction heater while loading a small graphite curcible. 25 percentage inside the tube suddenly the 2gates of MOSFETs started burning from the MOSFET bottom all collapsed can utell the reason sir

 

No idea since I was not there to see what or how your doing things.

 

I know this thread has been dormant for a couple of months, but, since folks are still apparently reading it I want to make a couple of comments:
1.-I am the guy who blew up several Mosfets while figuring out how to make the Chinese ZVS induction heaters work reliably.
https://spaco.org/Blacksmithing/ZVSInductionHeater/1000WattZVSInductionHeaterNotes.htm
Near the top of the page you will find the schematic that typifies the Chinese ZVS induction heaters.
This page also links to my other pages about induction heating, including the use of the 1800 watt and 2500 watt units.

2.-The Mosfet listed in the title of this thread concerns me. It is: IRFN 260.
All of the heaters I have use the IRFP260N.

3.-For D Ramesh: If you want to melt gold, you must use a 48 volt power supply.
Think about the output wattage----- 12 volts X 20 amps = 240 watts. 48 volts X 20 amps =960 watts.
Converting watts into BTUs: One watt = 3.4 BTU. So, 240 watts X 3.4 BTU = 816 BTU. And: 960 watts X 3.4 BTU = 3264 BTU.
That's not a lot of energy, especially since some of that power is lost in the circuitry and some is lost to convection and to radiation. A Bernzomatic TS-4000 propane torch puts out about 4000 BTU at best, just for reference.
As others have said, I suggest simply purchasing one of the available devices. I also think you will need the 2500 watt model for the work you intend to do.
Here's one link to a 2500 watt Kit:
https://www.aliexpress.com/item/400...chweb0_0,searchweb201602_1,searchweb201603_53

If you google "ZVS induction heater", you will get dozens of options. As others have said, you can't buy all the parts you need for the price of many of these kits.

 

-I am the guy who blew up several Mosfets while figuring out how to make the Chinese ZVS induction heaters work reliably.

Thank you for doing your experiments! They helped me to choose what to buy. Since then I give a link to your site whenever there is a question about these.