This small micro switch electromechanical switches since the advent of the 1930s , they continue to evolve to meet the requirements of different applications , 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 usually has three sizes : basic, with operating handle type, with operating handle and housing type . Micro switch is used and loved by the spring design .

   Whether you're looking for engineers used in residential heating or industrial boiler control thermostat, or used in large tank level switch , you need to consider the following five key characteristics : dimensions, electrical requirements ( voltage / current ) , reliability ( mechanical / electrical life ) , environmental factors ( hazard environment, temperature range ) and certification bodies . 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 characteristics

   Select micro switch size is very important. Switching characteristics are directly related to their size , including the current range, stroke and force . For example , one of the smallest on the market micro switch size 0.50 inches x0.236 inches x0.197 inches (LxWxH). While this is suitable for detecting the micro switch in the compact state of the circuit breaker , it is usually only breaking 0.1 to 3 amps (A) of the current stroke is shorter.

   Higher current applications usually require a large switch. Applications such as tanks , micro switch is used to detect the level of need to be able to provide a large stroke and withstand high currents. Usually level switch applications, switch to direct drive pump and carry large currents. This requires a rated current at 125VAC or 250VAC voltage of 20A or 25A of the large micro switch.

   Tip : Switch the smaller size , its itinerary and breaking currents can also be smaller.

   The switch also affects the dimensions of the operation force . Ideally , engineers need is a low operating power and high current capacity switch has . However, between these two parameters in fact requires a compromise . In a large current bear range while maintaining good contact micro switch requires a stronger spring , which will make the switch operating force and larger dimensions . Operating force range from pressurized pneumatic applications 2 grams applied to the solenoid valve (requires a large operating force ) in 8 oz . A switch on the market, the largest size is 1.94 inches x0.69 inches x1.3 inches (LxWxH).

   Engineers should also be noted that the differential trip switch - switch trip distance between the position and the reset position . Vary the threshold value depending on the application will be . For example, in applications where temperature switch , on / off operation point should be as close as possible , should be as low as 0.0001 inches differential travel . 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 from the low-power type to the type of electrical power to the load range of products for a variety of applications.

   Engineers must know the rated current and voltage (AC or DC) required for specific applications , to select the appropriate switch. Due to a variety of devices in all industries are committed to energy consumption, so the micro switch must be capable of operating at low current ( logic level loads ) and DC voltage .

   However, some applications can require breaking the large current and high voltage switches , 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 contacts , the contacts between the usually no current. When the switching contacts closed circuit connectivity . For NC -type contacts , the contacts between Typically there is a current . After switching the contacts open , the circuit is disconnected.

   Step 3 : Consider the environmental conditions

   Environmental requirements for micro-switch to select a great impact , especially in such as industrial control, medical equipment, and other requirements of high reliability and critical applications. Understand the application of environmental conditions , including air contaminants that may enter the switch , the switch in which the liquid and the operating temperature requirements.

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

   Step 4 : clear work life requirements

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

   A highly reliable micro switch before mechanical failure can operate from 10 to 20 million times, can operate from 50,000 to 100,000 times the maximum load before electrical failure .

   As slight price differences between different quality switch , you need to consider the total cost of use. Because you not only have to pay for the switch , but also in order to ensure trouble-free operation switch for a long time to pay . In many cases , the use of more reliable switching is required to offset the additional cost of the quality of its lower cost in use .

   Step 5 : Check the agency certification requirements

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

   When selecting 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 : What is the size of the switch needs ? The rated power is much needed ? Whether the low pressure applications ? Whether the switch need to be sealed ? Whether the switch needs to withstand extreme temperatures ? The need for certification of international organizations ? Whether critical applications ? Once clear of these problems, the application switches to choose the more easy.