Rudimentary IH Cooker Hack just by reshaping coil: can workload geometry match?

[Egzoset]

Salutations,

My needs are modest:  to inject in a matter of 2 ~ 3 seconds ~100 Joules in a tiny SS disc (punctured with 17 #53 holes) which measures only 12.6 mm (dia.) x 1 mm (thick) and weights no more than 0.75 g...  Instead of engaging into the process of designing a custom-made IH-driver i would hope it's a viable idea to reshape the coil of a ready-made commercially-available product like some IH Cooker i acquired a decade ago:



Please take note the calculated value didn't account for the presence for flux-concentration elements.

...

So, i'm seeking feedback impressions from people of all horizons, obviously with hands-on experience which may be of help as i think that's one proper place where to start asking exactly.

 

Eventually the workload is going to become more complex but i thought perhaps it will suffice to replace that coil with alternative samples and see if i can justify further investigation, eventually with the door opened on more ambitious goals.

Good day, have fun!!   

[T3sl4co1l]

Pretty tiny.  A ferrite core salvaged from a power supply would probably be a good fit.  Gap the pieces and place the "coin" in the middle.

I suppose a cooker might still be usable, if the inductance can be matched more or less.  If you aren't doing too many of these at a time, the coil won't get very hot, you can afford to skimp on the wire, in case you need to use thinner wire to meet the inductance requirement.

If the cooker isn't happy with that kind of load, maybe it needs some series inductance, in which case maybe use the original coil (pictured?) in series, with a copper pot on top to partially shield it, making its inductance adjustable without adding much resistance.

Tim

[Mads Barnkob]

Most IH cookers are quasi-resonant types, dirt cheap to make from the minimum required components, but also working on the brink of what is possible from a heat dissipation view due to frequency and load current. I did a analysis of the Ikea IH:

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I tried my luck with half the inductance of the original coil and I blew the IGBT and full-bridge rectifier up.

I have seen some Russian that added a LC secondary circuit with a parallel light bulb to act as dummy load, that way the "pot" detection wasn't trickered and he pulled some serious power out of it in a much smaller work coil.