How do (electric) Induction Cookers Work ?
Answers
They work on the principle of
electromagnetic induction, vibrating electromagnetic fields, eddy currents and
dissipation of heat. When current passes in metals/conductors, the electrons
collide continuously with atoms on the path. Electrons lose momentum and that is converted
in to heat. Again electrons gain speed due to potential difference and travel.
This process continues.
In the induction cooking system, we have a cooking
stove/platform and cookware (utensils, pans). The stove contains a strong
copper coil that passes AC current at high frequency. The current
produces magnetic field and flux around the coil. The varying current
produces varying magnetic fields (flux). So varying magnetic flux causes
eddy currents in ferromagnetic materials near the coil.
Eddy currents are
currents flowing within the cookware in small circles and loops.
Different magnetic fields and potentials result in different electric fields
and potentials at different points in the material of the cookware. Hence,
small loops of currents are produced. The resistance of the cookware
causes very quick heating up of the cookware. These heat up much faster
than regular gas based heating. This is similar to the heating up of
transformer core material, we often see them on roadside.
Induction cooking system is an energy efficient cooking
system. More than electric cooking or gas based. It is more
environment friendly, clean, less polluting and needs less ventilation in the
kitchen. It is healthier as we do not inhale gases that are emitted by
burning gases. It does not heat up kitchen so people will feel
comfortable. They save at least 10% of energy consumption.
These are introduced in to the market in this decade and are quite
popular in advanced countries. They have a thermostat and LED
display. The surface of the stove is ceramic and smooth. It does
not heat up as it is not ferromagnetic. The loss of heat in the copper coil is
very less. Cookware must be metallic and ferromagnetic. A ferromagnetic
flat plate may be used on top of the platform, to heat non-ferro cookware
through conduction. It is not efficient.
The cookware must have a flat bottom for better heating, as
then the distance of cookware will be nearer to the copper coil inside. A
wider flat bottom will be much better. The induction heater can detect
the presence of ferromagnetic material on the platform by the amount of energy
transferred. It can know the temperature of the surface in contact with
the cookware. It has automatic controls to start and switch off when
there is no vessel on top, of if it is not ferromagnetic. Also, if
any food item spills on the surface it is much easier to clean.
it works on the principal of electro magnetic induction