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bimetal switch

A bimetal switch is a temperature switch. As can be seen from the name, a bimetal switch consists of two metals, zinc and steel or brass and steel, which are rolled onto each other as strips or platelets and 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 to 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.

Example of a bimetal switch

Example of a bimetal switch

Bimetal switches are used as temperature switches which 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 addition to the switching function at a certaintemperature

, bimetal switches can also be used as overtemperature protection and temperature fuses. When the overtemperature is reached, they switch off the circuit.

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Englisch: bimetal switch
Updated at: 08.04.2013
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