Induction coils, turns, diameter, length, value, shape.

I decided to see what I can learn about induction coils. I used online induction coil calculator to get the value of several different coils then I made and tested about 15 different coils. After watching a video, how to use an industrial induction heater I understand the function of the electric circuit better. Each induction coil has to be designed for the metal part that is being heated. Coil diameter should be the smallest diameter you can make. Rectangle metal parts need rectangle induction coils. I always though L1 controlled circuit amps but not true, L2 controls amps at the part being heated. In my case circuit should idle at 25 amps then when metal part is inside the coil amps go up to 30. Mosfets explode at 34 amps. It takes 7 seconds for amps to drop from 30 to 20 when the metal is hotter than 1100 degrees metal is no longer magnetic. My induction heater circuit has been collecting dust for several years it is fun to learn new things.

Now I need to build a circuit with no center tap induction coil. I feel like, been there, done that, not very motivated to build another induction heater with water cooling and no center tap induction coil. It would be another good learning project but not very motivated to go there. Industrial induction heaters are not LC oscillators they are fix frequency.

When our weather gets worse I will need something to do beside looking at the TV.

If your MOSFETs are failing at 34 amps, you may consider adding current sensing and limiting circuits to protect them.

Can you post a better schematic pic, so I can better advise you.