How Does a Basic Linear Actuator Work?
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How Does a Basic Linear Actuator Work?

By SiliconIndia   |   Tuesday, 21 November 2017, 05:29 Hrs
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Linear actuators are devices that convert any rotary or spinning motion into a linear (straight) motion. In simple words, they help machins move forward and backward.

The most basic type of linear actuator is the screw actuator. It has an electric motor that gives motion to a threaded rod which gives a to-and-fro motion to the actuator.

These devices are used in a lot of machines such as forklifts, drill machines, industry machines, lift ramps, toys etc.

This article will explain the basic working mechanism of a linear actuator so that you can understand the internal matters of this device and feel comfortable if you ever need to replace some parts.

Linear Actuator Motor

Every electrical linear actuator has a motor in it that helps it to produce linear motion.

These motors are mostly at the bottom, under a cap and runs on DC current.

They work in a very simple manner, and are connected to a gear which is connected to two more gears.

As the motor is turned on, it forces these gears to rotate and thus the rod extends and retracts.

There’s a screw inside the actuator that spins clockwise and anti-clockwise to force the actuator out and back in. Also, there are DC brushes that provide current to the motor once the power is turned out.

If current passed is more than an actuator can bear then these DC brushes melt.

Lead Screw

One of the main component parts of a linear actuator is the lead screw.

This screw is embedded inside the shaft and is responsible for rotating the nut/inner tube inside an actuator.

Actuators come with different forces and that’s because they have different lead screws.

Different appliances require different amount of force to operate. Here’s where actuators having lead screws with more force is required.

Lead screws are made up of steel which is why they’re highly durable and do not break off easily while applying a rotatory force.

Usually, the pitch and width between the threads on the lead screw determines the force of the actuator.

Lead screws also determine whether an actuator will run slower or faster by controlling force.


There’s a nut which is attached to the inner tube and moves when the lead screw moves.

This nut is made up of metal or plastic and its purpose is to prevent any rotatory motion of the inner tube which is inside the actuator.

Limit Switches

Commonly, there are two limit switches inside an actuator whose job is to cut off electric current to the motor.

Apart from preventing the actuator to produce motion, they are also used as signal sending devices in many appliances.


Today, linear actuators are used in many applications such as industrial, medical, robotic etc. They work in a safe manner to provide linear motion and the required speed that an appliance need to operate.

You need to understand range of Powerjackmotion actuators and other such factors to truly understand how they work.

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