China Precision Micro Switch Manufacturer & Supplier

Definition of limit micro switch
A micro switch has a small contact spacing and a snap-action mechanism. The contact limit switch that performs the switch action with a specified stroke and force is covered by a shell, has an actuator on the outside, and has a small appearance. The figure below is an example of a typical micro switch structure. Micro switches are composed of 5 major components.

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Micro limit switch Terminology:
■ General terms
(1) General terms
Micro switch: A switch with a contact structure that has a small contact gap and a snap-action mechanism, performs a switching action with a specified stroke and a specified force, is covered by a housing, and has a drive rod on the outside. (Hereinafter referred to as a switch) With contacts: Among switch types, compared with semiconductor switches with switching characteristics, the switch function is achieved by mechanical switching of contacts. Contact form: The electrical input and output circuits that constitute contacts according to various uses [shown in (16)].
Rated value: Generally refers to the value that serves as a guarantee benchmark for switch characteristics and performance, such as rated current, rated voltage, etc. The premise is specific conditions (type of load, current, voltage, frequency, etc.).
Resin fixing (molded terminal): After wiring the terminal part with a wire, the part is fixed by filling with resin to eliminate the exposed live parts and improve the drip resistance.
Insulation resistance: Refers to the resistance value between non-connected terminals, between each terminal and a non-live metal part, and between each terminal and ground.
Withstand voltage: The critical value that does not cause insulation damage after applying high voltage to the specified measurement position for 1 minute.
Contact resistance: The resistance of the contact part of the contact, but generally refers to the resistance value including the conductor resistance of the spring and terminal part.
Vibration resistance: The vibration range in which the contact closed by vibration does not separate for more than the specified time when the micro switch is in use.
Shock resistance: Durable shock refers to the shock within the range that the micro switch will not be damaged by the mechanical shock during transportation or installation and meets the operating characteristics.
False operation shock? Refers to the shock range in which the contact closed by shock does not separate for more than the specified time when the micro switch is in use.
(2) Terms related to structure and construction

(3) Terms related to life
Mechanical life: The life of the switch when the contact is not energized and the overtravel (OT) is set to the specification value at the specified operating frequency.
Electrical life: The life of the switch when the rated load is connected to the contact and the overtravel (OT) is set to the specification value at the specified operating frequency.
(4) Standard test conditions
The test conditions of the switch are as follows.
Ambient temperature: 20±2℃, relative humidity: 65±5%RH, air pressure: 101.3kPa
(5) N level reference value
Indicates the failure level under a reliability of 60% (λ60).
λ60=0.5×10-6/times means that under a reliability of 60%, the failure rate is less than times.
(6) Contact shape and type
(7) Contact spacing
The contact spacing is specified as 0.25mm, 0.5mm, 1.0mm, and 1.8mm for four types of micro switches. The contact spacing is the target during design. When using, if the minimum contact spacing is required, please confirm and select. The general standard for the contact spacing is 0.5mm. For the same micro switch mechanism, the smaller the contact spacing, the smaller the MD, the higher the sensitivity, and the longer the mechanical life (lifespan), but it is disadvantageous in terms of DC breaking performance and vibration and shock resistance. The micro switch will wear out the contacts due to current switching, and the contact spacing will increase. As the MD increases, the sensitivity decreases. Therefore, in order to achieve high sensitivity, when using a micro switch with a contact spacing of 0.25mm, the switching current must be kept small to reduce the contact loss caused by current switching. Products with large contact spacing have good vibration resistance, impact resistance and circuit breaking performance.

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About this item
Package Content: 6 × Micro Limit Switch; Model No. : KW4-3Z-3
Hinge Lever Actuator, 1NO+1NC Contact Configuration.
Voltage & Current: AC 125V/250V 5A; Terminals: 3 Terminal
Switch Body Size: 2 x 1 x 0.7cm / 0.8″ x 0.4″ x 0.27″(L*W*H)
This Limit Switch can be used in various mechanical to control the position of moving parts of machines and plant.