The label on the device shown in post #36 is quite clear that DC is required: 24 to 36 volts. So THAT question is answered again.

Yes, it was clarified in post #36 AFTER I posted my original suggestion in post #27.

 

Once again @RickSmit may I see the website of the manufacturer? may I see the product specification? does it have a manual or instruction book? why do you refuse to answer these questions?

If you have followed the thread starter’s other threads, you’ll see this is a common pattern.

 

Evidently nobody believes that varying the application time of the energy can be an effective method of controlling the heatand the final temperature.The effect would be similar to faster PWM.And also simpler.

 

1000 Watt ZVS Induction Heater Notes

This is likely some of the best reading I came across on the subject. The link includes a schematic for a 1.0 KW induction heater. My read on PWM use on one of these is a mix of Yes and No and personally I never tried it. Been several years and I found the linked website still exist.

My use was annealing brass so once I had a scheme (timing and power) that worked I was happy.

Ron

 

If you have followed the thread starter’s other threads, you’ll see this is a common pattern.

Please show me your replies to my posts, which answer my questions...

 

Here is a suggestion that will not require designing a variable voltage DC supply with a high current capability. Consider that 1000 watts at 25 volts requires 40 amps, 360 watts would require about 13 amps. For a typical hobby application, with a 5% duty cycle and only occasional use, you should be able to get away with a 300 watt power transformer based supply quite well.
Unfortunately, rewinding any of the microwave oven transformers that I have seen, to provide close to 28 volts at 15 amps, will be a serious effort. For that current it will be wise to use #14 enameled wire. At four turns per volt that will require 108 turns. THAT will be a serious pain if the winding must be pulled thru if the laminations are welded, which is often the case.
I recommended, and still recommend, using a surplus 300 watt industrial controls step-down transformer in reverse. That would put 120 volts into the 480 volt primary, resulting in about 30 volts out of the 120 volt terminals. With the diode bridge the resulting DC out will be about 30 volts. No need to filter the DC output.

For the switching on/off, either a suitable solid state relay controlling the mains to the transformer, or even an electromagnetic relay can do. For the variable ON/OFF timing, there are such timers available with contact ratings adequate for controlling the relay coil.

 

After looking at the circuit shown in post #36 more closely, it looks like shunt zener diode regulation of both outputs. That is a poor choice for any high current power supply.
In addition, that entire circuit does not appear to be an adequate power supply.

well circuit diagrams all only show the same thing. transformer, rectifier, capacitor for smoothing. THATS IT... so i used it. and zeners in parallels to load, if the zeners die there will be no problem, the load voltage will drop it below 36 anyway. and it does work. at 24Vand 4 Amps they strongest adapter i have makes metal red hot....
and the low power output(side with LEDs) only can give about 1-2 amps, typical wall adapter for laptops

 

only HELP i found so far is:
*remove current limiting cap on AC input
*heavy rating compontents (yes ofcourse)
*maybe a rotary switch....
*time controlled output? (beside from a 555timer transistor motor control i do not even know how that could or would work in a ZVS circuit)nor how to make it.

besides those 4 points, no one has actually tried to help me design this thing, only criticized what i do and for why i need it.
I have a heater that needs 900W-1000W, i dnt have the power bank so i need to make one with potentially 2000W output for future use, and with a low power output side, if the lower don't work then it doesn't, i have other adapters i can use. But how hard is it so help me do this RIGHT, i need to to make 36V high current supply. voltage will drop on load, but all i have so far is not helping me.

 

The label on the device shown in post #36 is quite clear that DC is required: 24 to 36 volts. So THAT question is answered again.
And now, once again, I am asking as to why not simply control the TIME that the energy is applied?? I think that is frequently done in the induction hardening process, since time is much easier to control accurately. OR is that too different to even consider??
Certainly an adequate current non-regulated DC power supply is much simpler to create.
Or is this too far off topic??

how to do that?

 

Here is a suggestion that will not require designing a variable voltage DC supply with a high current capability. Consider that 1000 watts at 25 volts requires 40 amps, 360 watts would require about 13 amps. For a typical hobby application, with a 5% duty cycle and only occasional use, you should be able to get away with a 300 watt power transformer based supply quite well.
Unfortunately, rewinding any of the microwave oven transformers that I have seen, to provide close to 28 volts at 15 amps, will be a serious effort. For that current it will be wise to use #14 enameled wire. At four turns per volt that will require 108 turns. THAT will be a serious pain if the winding must be pulled thru if the laminations are welded, which is often the case.
I recommended, and still recommend, using a surplus 300 watt industrial controls step-down transformer in reverse. That would put 120 volts into the 480 volt primary, resulting in about 30 volts out of the 120 volt terminals. With the diode bridge the resulting DC out will be about 30 volts. No need to filter the DC output.

For the switching on/off, either a suitable solid state relay controlling the mains to the transformer, or even an electromagnetic relay can do. For the variable ON/OFF timing, there are such timers available with contact ratings adequate for controlling the relay coil.

there was mentioned before that controlling mosfets in the ZVS circuit with signaled output will be a bad idea. i do not know where to put your relay to keep things pure DC at variable output.... im struggling to get microwave transformers to break and rewind. i took transformers from a 2000W inverters and saw the primary and secondary. to reuse them.. FYI guys im in a country that uses 220V mains

 

OK, having 220 volt mains means that probably 480 to 120 transformers will not be available surplus.
as for full power for shorter time periods, it might be that timers like that, with one second time increments setable, would be available as surplus. They are also stock items at GRAINGER SUPPLY COMPANY.
A timer will need to control a relay, either solid -state or mechanical, to switch power to the DC supply. It is also possible to build a triac switch to do that switching.