Themostatic bimetal types

The type of thermostatic bimetal depends on the application and the available space. Elements can be roughly classified into four main groups:

Beams,

Coils,

Disks,

Formed elements.

Beams develop nearly linear motion. Coils (spiral, helical and double-helix coils) Disks move linearly or discontinuously (snap-action).

Formed elements include a wide range of regular or irregular shapes. The U-shape is very widespread. This type of element is employed when the available space will not permit the use of long, flat beams.

Generally speaking, coils are used wherever extensive motion is required, while beams are required for smaller movements to trip operating mechanisms.

some basic  mechanism of bimetal strip :

1.Simple temperature -controlled switch

This type of mechanism is usd for drect switching of an electrical circuit or a mechanical part. When current is passed directly through the element , slow contact motion may result in sparking between the contacts.

2.Counter-acting arrangements

Faster response and higher sensitivity reduces the risk of sparking between contacts in elements with direct electrical heating .

3.Auxiliary thermal switches

The thermostatic bimetal does not form part of the electrical circuit and responds solely to the ambient temperature .

4.Magnetic restraint

a permanent magnet resistrains deflection until the thermostatic bimetal had developed a force sufficient to overcome that of the magnet ,thus causing the contacts to spring parts . Conversely , the contacts close when the element has cooled down.

 Working procedure

Package :

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