How to power an induction hob coil

[Aiddyjay]

I'm working on a project for an idea I have but due to lack electrical knowledge I'm having trouble. Can someone tell me the easiest way to directly power an Induction coil (from a cooker) at a low voltage? I have dismantled a stand alone cooker for my project but even on the lowest setting it's too powerful for my needs. Can anyone help?
Many thanks

 

[Arouse1973]

Hello and welcome to EP
Can you tell us a bit more about your project. How powerful do you need it, what's it doing?
Thanks
Adam

 

[Aiddyjay]

Hi, thanks for your reply. Sorry this all maybe a bit vague as I've got what I need in my head but not the knowledge to do it! I essentially need to use the coil to warm up a thin sheet of steel to about 50 degrees C through about 1/4inch of plastic. On its current lowest setting it's up to about 80-90 degrees C, way to hot for my needs. Also I could do with powering the coil without all the extras on the cooker ie: control panel, timers etc..

 

[Arouse1973]

Does the plate need to be steel? Can you increase the thickness of the plastic? Can you also take some pictures of the HOB circuitry so we can have a look.
Adam

 

[Minder]

Did you try the spacer/stand off method to reduce the inductive field range.
You may have to get a schematic of the cooker in order to modify it, sometimes this is attached at the back etc.
M.

 

[Aiddyjay]

I can increase the thickness of the plastic if needed but moving the sheet of steel away from the coil it cannot detect it's presence and does not turn on.

 

[Minder]

How about the thickness of steel, can it be reduced?
M.

 

[Arouse1973]

I can increase the thickness of the plastic if needed but moving the sheet of steel away from the coil it cannot detect it's presence and does not turn on.

You may not need to move it very far. Does it need to be solid steel? What about a material change? What about a small heat sink? Have you thought of drilling some holes in the material?
Adam

 

[Minder]

Also you could experiment to try seeing what the minimum amount of ferrous material (steel) could be used to enable the stove turn on?
M.

 

[Aiddyjay]

Would thinner steel get hotter/quicker? I could try putting holes in it. Can't go thicker steel as it needs to be as light as possible. I can use less steel to the point it still turns on but the steel will still reach a too hot temperature.

 

[Minder]

Maybe arrange some kind of cycling timer, if the lowest heat is too high?
Varying on/off times may be the answer if it is possible.
M.

 

[Aiddyjay]

Maybe a timer option could be the answer. I'm assuming I cannot connect an adjustable voltage ac transformer direct to the coil?

 

[Minder]

I think you would run into detection issues still.
Unless the detection were disabled.
M.