This small micro switch electromechanical switches from its inception in the 1930s, they continue to develop in order to meet different application requirements, including aerospace, appliances, boiler control, medical equipment, sprinkler systems, test equipment, timers, and vending machines. Micro switch is usually used to detect temperature, position and level.

    Precision micro-switch is usually available in three sizes: Basic version with operating handle type, with operating handle and shell type. Micro switch is used by Zhi and spring design.

    Whether you're looking for engineers are used in residential heating or industrial boiler control thermostat, or used in large tank level switch, we need to consider the following five key characteristics: Dimensions and electrical requirements (voltage / current ), reliability (mechanical / electrical life), environmental factors (hazard environment, temperature range) and institutional certification. The following five key steps can help you choose suitable for your specific application micro switch.

    Step 1: Learn how to switch dimensions affect other properties

    Select size when micro switch is very important. Switch size is directly related to its characteristics, including current range, itinerary and operating force. For example, one of the smallest on the market micro switch size 0.50 inches x0.236 inches x0.197 inches (LxWxH). Although this tiny switches are suited in the compact circuit for detecting the state of the circuit breaker, but it is usually only breaking 0.1 to 3 amps (A) of the current, the trip is shorter.

    Need more current applications usually require larger switch. Applications, such as fuel tank, for detecting the level of the micro switch is required to provide large travel and to withstand high currents. Usually in the level switch applications, switch to direct drive pumps and carry large currents. This requires a rated current at 125VAC or 250VAC 20A or 25A voltage when a large micro switch.

    Tip: Switch size is smaller, breaking his itinerary and to the smaller current.

    Also, the switch also affects the dimensions of the operating force. Ideally, engineers need is a low operating force and a high current capacity of the switch. In fact require a compromise between the two parameters. Bear in providing high current range while maintaining good contact, micro switch will need a stronger spring, and this will make the switch operating force and dimensions larger. Operating force can range from pneumatic booster 2 grams of the application to the solenoid valves (requires a large operation force) in 8 ounces. A switch market, the largest size of 1.94 inches x0.69 inches x1.3 inches (LxWxH).

    Engineers should also be noted that the differential trip switch - switch position and reset the trip distance between the positions. Its threshold depending on the application will be different. For example, in applications where temperature switch, on / off operation point should be as close as possible, differential travel should be as low as 0.0001 inches. However, in liquid pump applications, the differential travel too close to the water supply pump may cause too frequent stops, shortening the life of the pump.

  Step 2: Know your electrical requirements

    Micro Switch can often breaking from 5mA/5VDC to 25A/250VAC current. Micro Switch product line provides a low-power type to the power load from the electrical type a range of products for a variety of applications.

    Engineers must know the specific application required rated current and voltage (AC or DC), to select the appropriate switch. Since all sectors are committed to low power various devices, so micro switch must be able at low current (logic level loads) and DC voltage.

    However, there are some applications need to be able breaking high current and high voltage switch, such as industrial pump applications.

    In addition to the load requirements, engineers must also select the appropriate circuit. Switch contacts must be normally open (NO) and normally closed (NC) in one. For NO type contact, usually no current through the contacts. When the switch is activated, the contacts close, the circuit connected. For NC type contacts, usually there is a current contacts. When the switch is activated, the contacts open, the circuit is disconnected.

    Step 3: Consider the environmental conditions

    Environmental requirements on the choice of micro switches great influence, especially in such as industrial control, medical equipment, and other mission-critical applications that require high reliability and medium. Understand the application of environmental conditions including air contaminants may enter the switch, the switch and the operating temperature of the liquid in which the requirements.

    For applications under harsh environmental conditions, you need to choose has a wide operating temperature range of hermetically sealed switches. Highly reliable micro-switches can be -65 degrees Fahrenheit (-54 degrees Celsius) to 350 degrees F (177 degrees C) temperature range, can easily cope with a variety of applications. At the same time, pay attention to the switch should be at least IP67 protection class level, in order to prevent liquid intrusion. This eliminates the need to spend a lot of time designing an enclosure to achieve the same degree of protection.

Step 4: Identify working life requirements

    Switch reliability is critical. You need to clear an application in the end how many times the electrical and mechanical operating life? Different switches have different contact material, the shell and the terminal to meet different application needs of the electrical and mechanical life.

    A highly reliable micro-switches in mechanical failure before operation 10 to 20 million times before failure in the electrical operating at maximum load from 50,000 to 100,000 times.

    As for switching between different qualities subtle price difference, you will need to take into account the total cost of use. Because you not only want to pay for the switch, but also to ensure trouble-free operation switch for a long time to pay. In many cases, the use of more reliable switching the additional cost will be lower in the course of the warranty costs offset.

    Step 5: Check the agency certification requirements

    Select the line with the requirements of various international electrical switches can help you simplify product design for different regions. Some of the major certification standards, including the United States UL, cUL certification or Canadian CSA, ENEC European certification and China CQC certification.

    In the choice of micro switch, you need to consider a number of factors, such as dimensions, load requirements, work environment, and reliability, it is necessary to understand the actual application requirements: the need for what size switch? What is the rated power needed? Whether the low-voltage applications? Switch is to be sealed? Switch is needed to withstand extreme temperatures? The need for international organizations certified? Whether critical applications? Once clear of these problems, the application select the appropriate switch is much easier.