How to Use an External Limit Switch with a Linear Actuator

Posted by 1Cary on

An external limit switch is a very handy and cost effective means of controlling the travel of a linear actuator. Here we will go over how to use an external limit switch with a linear actuator.

Most electric linear actuators are made with built-in limit switches. This means you are able to adjust the travel of the stroke to your precise desired position. Not all linear actuators are built limit switches.
So what do you do when the linear actuators stroke is longer than you need?
Installing an external limit switch is the simplest and most affordable method to control the travel in electric linear actuators where the limit switch is either non-adjustable or non-existent.

There are three ways to control the stroke:
Limit extension
Limit retraction
Limit both extension and retraction

What is a Built-In Linear Actuator Limit Switch?
All our linear actuators have internal limit switches at the fully extended and retracted positions. These limit switches ensure that when you fully extend (or retract) the actuator it will automatically shut off preventing the motor burning out and/or doing damage to the body of the actuator. However, these limits not adjustable.
This is a very important feature because if it did not shut off the motor, it would continue to draw power which would very quickly burn it out.

What is an External Limit Switch?
External limit switches are used to make or break an electrical connection. It can be designed in many forms, but to put simply, it’s a device with a Roller Plunger (or Plunger or Roller Lever etc) that, once moved, will either close or open an electrical circuit. They are also designed in a variety of sizes and power to accommodate a wide range of motion control devices, from small electric linear actuators, to large high-power heavy-duty linear actuators.

The Roller Plunger (or Plunger or Roller Lever etc) must be moved by another force, Common methods of activation include:
Directly by the linear actuator;
Something attached to the linear actuator.

If you do not require the full stroke of your actuator you can use the external limit switch to cut power to the linear actuator motor once it reaches your desired travel distance.
External limit switches are easy to connect to your linear actuator and as previously discussed, provide a simple solution to stop the actuator from moving past a set position of your customization.