I've had occasion to work on some commercial induction heaters, and they all used water cooled induction coils. I was wondering how the current crop of induction hotplate gizmos deal with self heating of coils.
I have a throw away type unit that claims 1800 watts, and I don't question that that's probably close to what it can consume. It really makes a gas stove look weak when it comes to boiling water and cooking stuff.
the coil is just some stranded wire in a pancake type spiral. There's no ferrite, and PFC seems integral to the unit as there are no large filter caps.
There's a temp sensor heatsink compounded to the top glass which it used for controlling the unit in a series of preset temperture ranges. It may also double some sort of protection device, while under control of the microprocessor running the thing.
The power levels the circuit run at are impressive and the cooling fan seem to only be there to dissipate heat from the upper cooking surface itself.
It's hit about 11 months of use and of course in it's chinese build quality the only part to have broken is the flexible plastic bezel over the pushbuttons. Most of the buttons are cracked just over the switch. A layer of bookbinding tape should make me forger that ever happened.