Bimetal LS type MT-32/3H (12-18)

Bimetal LS type MT-32/3H (12-18)

[Bimetal LS type MT-32/3H (12-18)](https://www.automation24.ir/product-2089/%D8%A8%DB%8C%D9%85%D8%AA%D8 %A7%D9%84-ls-%D8%AA%DB%8C%D9%BE-mt32-3h-\(1218\))

### B-metal key:

The non-metal switch is used to protect the electric motor and other electrical equipment against overcurrent. The structure of this switch consists of 2 non-homogeneous metals that have different longitudinal expansion coefficients and are pressed together in a cold state. How the switch works Bimetal is such that due to the increase in the amount of current passing through the rated current (excess current), the temperature increases and as a result the length of the two metals increases and since the materials of the two metals are different, the two metals bend. This action causes disconnection or connection of the circuit.


## Bimetals are divided into three categories in terms of performance after breaking the circuit:

Hand or manual without metal

automatic bimetal (Auto)

Manual and automatic without metal

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### Hand-held metal:

Manual bimetals cool down and return to their original state after functioning and disconnecting the circuit, but the contacts that have changed status remain in the same state, so to reconnect, you have to press the reset button on the bimetal manually. It is compressed so that the contacts return to their original state and the circuit is ready for reconnection. This type of bimetal is used in systems whose control circuit is automatic or non-automatic.



### Automatic bimetal:

When an error (overload) occurs in the electrical systems, the automatic bimetal switches off the relevant circuit through a closed contact, and after a certain period of time when it has cooled down, the contacts return to their original state. Metals are used in systems whose control circuits are manually controlled, such as star and triangle starting circuits of three-phase electric motors, aerial cranes, elevators, industrial devices, electric benders, guillotines, press machines, etc. .



### Manual and automatic bimetal:

Bimetal manufacturing factories do not make manual and automatic bimetals separately in order to prevent the wide variety of this product. Rather, both bimetal modes are made in one set and are used to change modes by a key installed on it.



## Important points in choosing bimetal:

Bimetal is selected according to the nominal current value of the electrical device, or the amount of current passing through the place where the bimetal is placed. Because the current absorbed by electrical devices, especially electric motors, is different in different loads. As a result, in order to select the appropriate bimetal, the current passing through the installation site should be obtained, and the bimetal should be selected within the range of the rated current and set exactly on the rated current (passing current).