bimetal switch
A bimetal switch is a temperature switch. As can be seen from the name, a bimetallic switch consists of two metals, zinc and steel or brass and steel, which are rolled onto each other as strips or plateletsand which have different coefficients of thermal expansion.
When the temperature changes, the two metals of bimetallic switches expand differently and, being firmly bonded together, they bend. This bending actuates a snap-action switch, which in turn opens or closes a switch contact. The temperature range of bimetallic switches is between 0 °C and 250 °C. They can be designed in platelet, strip or spiral form. Mechanical regulators can be used to adjust the distance for tripping and thus change the temperature range.
Bimetal switches are used as temperature switches that trigger a switching contact at a certain temperature and thus switch a fan, a cooling pump or a heating loop on or off. You can find bimetal switches as thermostats in circuit breakers, heating plates, fan heaters, boilers, toasters, coffee machines, in power supplies, irons or as motor protection switches. In other words, everywhere where an action must be triggered when a temperature is reached.
In addition to the switching function at a certain temperature, bimetal switches can also be used as overtemperature protection and temperature fuses. When the overtemperature is reached, they switch off the circuit.