High resistance or low resistance for induction cooktops?

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SUMMARY

Induction cooktops operate by generating a changing magnetic field through an AC current, which induces an electromotive force (emf) in a conductor, resulting in heat. The relationship between power loss and resistance is defined by the equation P=I^2 * R, indicating that high resistance leads to significant power loss. However, low resistance is preferable for cookware, such as copper or aluminum pots, as it allows for higher current flow and reduced heat loss during cooking. This discussion clarifies that while high resistance is generally avoided in electrical applications, low resistance is advantageous for induction cooking efficiency.

PREREQUISITES
  • Understanding of induction heating principles
  • Familiarity with Ohm's Law (V = IR)
  • Knowledge of power loss calculations (P=I^2 * R)
  • Basic concepts of electromotive force (emf)
NEXT STEPS
  • Research the properties of copper and aluminum in induction cooking
  • Explore the design considerations for induction cooktop systems
  • Learn about the efficiency of different cookware materials in induction heating
  • Investigate the impact of resistance on electrical appliances beyond cooking
USEFUL FOR

Engineers, appliance designers, and culinary professionals interested in optimizing induction cooking efficiency and understanding the material properties of cookware.

Nerkiot
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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.
 
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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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