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What Is a DC Linear Actuator?

Paul Scott
Paul Scott

A DC linear actuator is an electromagnetic switching or actuation device used to activate a range of secondary mechanisms. These devices are defined by two specific characteristics — a linear actuation output and the exclusive use of a direct current (DC) power source. The actuators transfer the rotational output of their motors to the final straight-line actuation movement via gear trains or lead screw arrangements. The direct current power sources used to drive the DC linear actuator typically require the inclusion of a step down and rectification unit, but do offer the benefits inherent of a low-voltage installation. This type of actuator sees service in a broad range of industrial, automotive, and domestic environments, including machine actuators, door and vent controllers, and TV lifts.

Also known as linear motors, straight-line actuators take the rotary motion of an electric motor and translate it into a straight line, or linear working output. This straight-line motion is used to operate a huge number of different devices and processes, from tiny, precision camera functions to massive industrial machinery components. The DC linear actuator is one specific example of this family of linear motors, which is defined by its use of direct current (DC) motors as a power source as well as its linear motion output. DC power is produced by removing the polarity reversal cycle from mains alternating current (AC) power using a rectifier. This means that a DC linear actuator will either have an integral rectification circuit or will require the installation of one prior to use.

DC motors are often used as actuators.
DC motors are often used as actuators.

These DC actuators work in the same way as other linear motors and typically achieve the rotary/linear transfer via a gear or lead screw arrangement. Gear arrangements commonly used in these actuators include worm and rack-and-pinion types. The DC linear actuator is available in a large range of sizes, actuation lengths, and power outputs. The smaller examples may only extend by an inch or so and exert less than 10 pounds (4.5 kg) of pressure, while heavy-duty examples can extend several feet and exert in excess of 1,000 pounds (454 kg) of pressure.

The DC linear actuator is often considered a desirable actuation solution due to the benefits that go hand-in-hand with DC installations. These include low voltage and generally lower currents involved, lack of electrocution potential, reduced cable size requirements, and low running costs. These features coupled with the general efficiency and power of linear actuators make the DC linear actuator a good choice for both heavy industrial and light domestic installations.

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    • DC motors are often used as actuators.
      By: sethuphoto
      DC motors are often used as actuators.