Micro Switch Included Limit Switch

Micro Switch Included Limit Switch

Micro Switch Included Limit Switch

Do You Know The Difference Between A Micro Switch And A Limit Switch?

The difference between limit switches and micro switches is mainly shown in appearance and application scenarios.

A limit switch has sturdy housing, and where it comes in contact with the object, a buffer distance is retracted by a spring. The internal microswitch can react immediately when it comes to contact with the object. Because of the buffer distance, the micro switch is protected.

A micro switch, also known as a miniature snap-action switch, is a type of momentary contact switch used widely in automotive, industrial, and medical instruments as a sensor. The switch is termed “micro” on its name, which first started manufacturing it commercially. The actuator of these switches often has a hinged wheel placed above a push button. This switch is widely used in control system applications such as door interlocks, safety switches in elevators, vending machines, etc. With a diverse range of engineering applications, micro switches are available in various switch configurations, housing materials, actuator styles, etc.


What Is A Limit Switch?

A limit switch definition is a daily device that sends an electrical signal by physical interaction. The limit switch usually detects the actual object and sends an electrical signal to the machine, and then the machine will act as the predicted process.

These switches are initially used to define an object’s travel limit, and as a result, they were named limit switches.


Limit Switch Types

There are four general limit switches types:


  1. Whisker Limit Switch
  2. Roller Limit Switch
  3. Lever Limit Switch
  4. Plunger Limit Switch


But the four types of the limit switch are the standard. People apply the four types of microswitch to distinguish daily use. And depending on the actual application, a limit switch may be a combination of 2 general types, such as a roller-lever.


Limit Switches Applications

Limit Switches can be found in several everyday devices:

They are used in microwaves to check that the door is closed before an operation is allowed. 

They are used in elevators to notify the system that the cabin has reached the desired floor. 

Limit Switches are used in washing machine lids as permissive to start the wash cycle.

When you open the fridge door, a light comes on inside. How does that happen? Yes. You guessed it! A limit switch detects whether the fridge door is open or closed.

Let’s look at another application of a limit switch you may encounter at home. A limit switch on many overhead garage doors stops the door’s movement when it reaches its fully opened position.


Limit Switches In Elevator Systems

Elevator systems commonly require limit switches for various purposes by building codes. They are used for position detection, safety, and the operational state of the elevator. The types used in this application are rated for an even more significant number of cycles as they constantly experience actuator movement through the system’s life.


Limit Switches In Household Systems

Limit Switches are used in everyday appliances: fridges, tea kettles, mixers, washers, dryers, and more. The limit switches in these appliances are the same in principle but different in reliability. In other words, they operate similarly but may fail much faster than their manufacturing counterparts.


How Do Limit Switches Work?

Limit micro switches are electromechanical devices with an actuator mechanically linked to an electrical switch. When an object contacts the actuator, the limit switch will operate, causing an electrical connection to make or break.


Why Is The Limit Switch Necessary?

When manufacturers want to connect the physical and electrical devices, they will first choose limit switches, Just for the inexpensive limit switches. Countless limit switches are found in manufacturing. They are used as control devices and safety devices for machinery and personnel. The limit switches will send a digital signal to the control system in all cases. The system can take appropriate action based on the hardware and software tied to said switches.

Limit switches have a long history. People apply it most daily life and industry manufacturing. The widely used limit switches make the cost lower than before!

In other words, Limit switches play a vital role in manufacturing due to their simplicity and low cost.


Configurations Of Limit Switches

Limit switches configurations are available in several types: Normally Open, Normally Closed, or Combination of Two.

Normally Open | The limit switch will allow the current to pass once it is actuated. In the resting state, no current will pass through the switch.

Normal Closed | The limit switch will stop the current once it is actuated. In the resting state, the current will flow freely.

Combination of Two | The limit switch will provide a set of contacts used in Normally Open (NO) and Normally Closed (NC) circuits.


Limit Switches Symbols 

Depending on the origin of the electrical schematic, you may see limit switches drawn in different ways. The International Electrotechnical Commission (IEC) and the National Electrical Manufacturers Association (NEMA) have slightly different symbols.


Limit Switches In Action

Now that you’ve seen the limit switch in action, you are probably thinking about some of the applications you have seen. For example, you might see limit switches operated by a container on an assembly line, a rotating machine part, or other moving mechanical objects. Limit switches could be used to count passing objects or determine the position of a hydraulic cylinder.


How To Know The Bad Or Good Of The Limit Switches?

You can often use a basic ohmmeter or Digital Multimeter (DMM)! It’s possible to determine whether or not a limit switch is bad. 

First, disconnect the limit switch from the system and apply the ohmmeter leads to each terminal. Then, If the limit switch is normally open (NO), the resistance should be very high. 

Next, If it’s typically closed (NC), the resistance should be zero. 

At Last, Toggle the limit switch into the active position and measure the resistance. It should be the opposite in this setting. If the transition does not occur, the limit switch is bad.


Proximity Sensor VS Limit Switch

Limit switches are slowly starting to disappear from many industrial applications. Proximity sensors are replacing them. Unlike a limit switch, a proximity sensor has no mechanical moving parts. A proximity sensor performs the switching action with electronic switches.

Limit switches will not wholly disappear soon as they outshine their proximity switch counterpart in their ruggedness and reliable operation in challenging environments. Generally speaking, limit switches can handle much higher current values than proximity sensors.


Micro Switch Inside Structure

Let’s look inside a micro switch, a limit switch type. Inside microswitch has two limit switches operating together and sharing a common terminal. One limit switch is usually open, and the other is typically closed.

Technically correct, the microswitch configuration is Single Pole Double Throw, commonly referred to as SPDT. This indicates that both switches are mechanically connected and will operate simultaneously.


Micro Switch Simple Circuit

Alright, let’s connect the microswitch to a lamp circuit. The Red lamp is on in the inactive state as the device is not being operated by an object pushing the Trigger. The device will activate when the Trigger is pushed, and the Green lamp will come on.


A Limit Switch Cannot Be Used As A Safety Interlock.

A limit switch is mainly used to limit the travel of the machine. It cannot be used as a safety interlock. But the micro switch does it!

Safety interlock switches are a means of safeguarding that monitors the position of a guard or gate. You can use them to shut off power, control personnel access, and prevent a machine from starting when the guard is open.



OK, let’s review…

– There are four general types of limit switches: whisker, roller, lever, and plunger.

– Limit switches are electromechanical devices operated by a physical force applied by an object.

– A limit switch is an electromechanical device consisting of an actuator mechanically linked to an electrical switch.

– Limit switches are available in several switch configurations: Normally Open, Closed, or one.

– Depending on the origin of the electrical schematic, you may see limit switches drawn in different ways.

– Proximity sensors in many applications are replacing limit switches.

If you have questions about using Limit switches, add them in the comments below, and we will get back to you in less than 24 hours.


Unionwell Micro Switch Manufacturer

Huizhou Unionwell Sensing & Control Electronics Co., Ltd specializes in quality micro switches for the automotive industry and white goods of home appliances. Main products include basic micro switches, waterproof switches, air pressure switches, mechanical keyboard switches, door switches, etc.

For better guarantee on pricing, lead time, and quality control, we acquired Huizhou Greetech Electronics Co., Ltd in 2021. We made it our China production base with over 1000 employees and 260 million pieces/year production capacity. 

Huizhou Greetech is an ISO9001, IATF16949 and ISO14001 certified micro switch manufacturer whose entire series of products have been granted global access permit certifications, including ENEC, UL, CE, CB, etc. our global reach covers North America, Europe, Asia, and South America. 

Most of our business partners/end customers are Global 500 enterprises, including world-famous home appliance brands and leading automotive suppliers in North America and Europe.

Shortly, we are launching a new industrial base at Longmen, Huizhou, Guangdong Province; automation equipment will be introduced, which would massively improve the switch production capacity from 260 million pieces to over 1.3 billion pieces/year. 

A one-stop system will cover product development, precision molding, injection moulding, precision stamping, automated equipment R&D, assembling, and testing. 

The professional sales team is on hand to provide assistance and quick response to 3D drawing requests, price quotes, and access to an adequate sample program that allows engineers to test and qualify switches for their end product applications.


Unionwell Limit Switches Products Lists >>


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