What Kind Of Magnets Are Used in Rice Cookers? Working Principle Of Rice Cooker Magnet

What kind of magnets are used in rice cookers? Working principle of rice cooker magnet

 

What is a rice cooker magnet?

The magnetic steel of the rice cooker refers to the overheat release switch installed in the center of the heating plate of the electric rice cooker. This switch works by using the property that the permanent magnet becomes weaker after overheating, so it is called a magnetic steel.

 

Working principle of rice cooker magnet

The basic principle is bimetal temperature control.

It is a temperature control element, also called a temperature-sensitive magnetic steel. It usually leaves the factory with a fixed temperature value. After reaching a certain temperature, the magnetic steel will demagnetize. When the rice is cooked, it will rely on the reaction force of the spring to disconnect the power supply.

When cooking, press the start switch by hand, and the permanent magnet and the soft magnet are attracted through the transmission rod. The suction force is greater than the elastic force of the spring and the self-gravity of the permanent magnet, so the permanent magnet will not fall, the contact is closed, and the circuit is connected. The heating plate starts to heat up. After the rice is cooked, the temperature continues to rise, and when it reaches 103°C, the soft magnet suddenly loses its magnetism, and the permanent magnet falls under the action of its own gravity and spring force, and the contact is separated by the transmission rod, the circuit is disconnected, and the heating plate stops fever. This acts as a temperature limiter.

 

When the temperature drops, the bimetal gradually recovers. When the temperature is lower than the heat preservation temperature, the position of the moving piece is lower than the position of the fulcrum. Under the action of the energy storage shrapnel, the contact is closed and the circuit is connected. In this way, although the temperature limiter has been disconnected, the continuous action of the insulator can achieve the purpose of heat preservation.

Working temperature of rice cooker magnetic steel temperature limiter

When heated to 103-105 degrees, it will automatically jump, but the magnet used is in this working temperature range (using NdFeB with M performance).