principle of operation
The working principle of the electric kettle is that the steam generated when the water boils deforms the bimetal of the steam temperature sensing element, and the power switch is pushed by the deformed lever principle, so that the electric kettle is automatically powered off after the water boils. Its power failure can't be automatically reset, so the kettle won't be automatically reheated after power failure.
Using PTC heating element instead of heating tube can effectively prevent the fire danger caused by dry burning. The dry burning temperature of PTC heating element can be set at any temperature between 150℃ and 250℃. When the temperature reaches the set temperature, the resistance of PTC element increases rapidly, and the heating power drops sharply, so that the temperature is kept at the set temperature and will not continue to rise. The automatic temperature control performance of PTC heating element is absolutely reliable. It controls the temperature through the change of resistance in PTC body, not through any contact. So many high-grade electric kettles use PTC heating elements. However, many electric kettle designers are not used to using PTC heating elements, and PTC is expensive and bulky, so its application is limited.
PTC heating element has great advantages in heat preservation of electric kettle. The insulation power of the electric kettle is relatively small, and the use of PTC heating elements will not increase the cost. PTC heating element has the function of preventing dry burning, and the dry burning power is about one tenth of that of boiling water. When the temperature control element fails, the temperature of PTC itself remains low, so there is no danger.