Induction stove, microwave oven
What is difference between working principles of microwave oven and induction stove? Why are only stainless steel vessels preferred for the induction stove instead of copper, brass and aluminium, which are good conductors of heat?
V.K. PRAHLADA RAO
Bangalore
While there is some similarity in the working of microwave oven and induction stove as both consume electric energy for heating, the similarity ends there. Working principles of microwave oven and induction stove are poles apart. In case of microwave oven, microwaves which are of low wave lengths (about 12 cm) but contain high energy, are produced through a device known as magnetron. The microwaves are reflected on to the cooking vessel where the food is stored.
The high energy microwaves vibrate the molecules of the food at very high frequency (2500,000000 per sec) which in turn produces high quantity of heat energy. The heating of food is more uniform as compared to other methods. However, only non metallic containers can be used to store food inside the oven as metallic containers are likely to reflect back the micro waves.
Also one has to take extra precautions while using the microwave oven as the high energy waves can harm the living cells of the body.
In case of an induction stove, the heat energy is produced through induction effect. There is an electric coil below the top of induction stove. When varying (alternating) electric current is passed through the coil, a magnetic field is produced around it.
When a steel or any other ferro-magnetic metal vessel is kept on the top of the induction stove, it produces eddy electric current in the vessel itself. Due to resistivity of the metal, when the electric current is passed in the vessel, it produces heat energy (as produced in an electric heater) which in turn heats up the food. However, limitation of the induction stove is that vessels which are of non ferro-magnetic metal like copper, aluminium, or of glass cannot be used as there will be no eddy current in them.
S.P.S. JAIN
Former Member, Engineering, Indian Railways
Greater Noida, Uttar Pradesh
