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High resistance or low resistance for induction cooktops?

  1. Mar 31, 2014 #1
    Induction heating relies on an ac current to produce a changing magnetic field and hence a conductor will experience a changing magnetic flux. This induces an emf and then a current and thus heat.


    Heat generated is P=I^2 * R
    From this, it would appear that a very high resistance would lead to a very large power loss/heat generated.
    However, V = IR, so in reality a very low resistance will lead to a high current (provided induced EMF is the same). Therefore a pot with very low resistance is desirable.

    Is that end of story? Is it simply do reduce heat loss, you actually should increase resistance as much as possible? Because that sounds really counter-intuitive. Sure in many applications where you don't want to lose all your power in the wires due to high resistance, you still give resistance low so a current can flow to the appliance, but when cooking, is a very low resistance favourable?

    The question in particular is referring to as to whether a copper or aluminium pot should be used.
     
  2. jcsd
  3. Mar 31, 2014 #2

    CWatters

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    I can think of a good reason why you wouldn't any design to create a significant voltage difference between two different parts of the pot :-)

    Anyway probably worth you looking at this for why different materials are preferred...

    http://en.wikipedia.org/wiki/Induction_cooking
     
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