What is a micro switch?

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A micro switch is a compact switch that converts physical force into a driving force that turns an electric switch on or off so that internal contacts can be opened or closed.


Micro switches are widely used as a source of electrical signals that represent the operation of mechanical devices at specific locations. In addition, it allows the contact to be opened or closed quickly, so it can also be used to control the current supplied to the electrical load device used in the electrical equipment.


Typically, micro switches used in power equipment can be turned on or off to conduct or cut off, for example, a direct current with a maximum voltage of 250V and a maximum current of 16A.

micro switch

However, under the opening operation, the prior art micro switch has only a short separation distance between the built-in movable contact and the fixed contact, and is not equipped to quickly eliminate the movable contact and the fixed contact during the opening operation. Any component that generates an arc between contacts.


Therefore, the prior art micro switch can be turned on or off to conduct or cut off, for example, a voltage of 250V and a direct current of 0.3A. In other words, the DC level that can be conducted or cut off sharply drops.


For the cycle of alternating current with a period with a positive value, a time point of zero current, and a period with a negative value, the micro switch is cut off (opened) at the time point when the current becomes zero, so that the cut off (prevent) is relatively large Alternating current.


However, direct current does not have a zero point, so the amount of direct current that can be cut off by turning off the micro switch can drop sharply.


On the contrary, the circuit breaker of the electric equipment uses the electric motor as the driving source for storing the energy of its internal trip spring.

micro switch 

Here, in the case of constructing a control circuit including the electric motor and a magnetic contactor for controlling the driving/stopping of the electric motor, such a configuration requires a miniature capable of cutting off direct current having a voltage higher than 250V and a current of 1.0A, for example. switch.


However, the distance between the movable contact and the fixed contact of the prior art micro switch is too short, so that only a small amount of direct current is cut off. Therefore, the micro switch is not suitable for controlling the operation of the electric motor installed in the electric equipment.


In addition, since the prior art micro switch is not equipped with a member that quickly extinguishes the arc generated between the movable contact and the fixed contact when the movable contact is separated from the fixed contact, it cannot effectively cut off the large direct current.


Therefore, when a large direct current is generated, the motor and the micro switch arranged on the rear side of the micro switch may be damaged. Moreover, the trip spring of the circuit breaker cannot be stored, so that the circuit breaker may not be operated.


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