How Do Electric Actuators Work?

Electric actuators are common in many different types of equipment across dozens of industries. Whether it's automating industrial tasks or making small adjustments in everyday devices, actuators are crucial. This article aims to unravel the basics of how electric actuators do their job, revealing the engineering brilliance behind them. We'll have a look at the essential principles and parts that make electric actuators work, showing how they drive a wide range of applications. Keep reading to learn how electric actuators work from internal components and control systems through to motor types and physical design.

4 Types of Electric Actuators

Depending on how you categorize them, there are many different types of electric actuators. It’s possible to categorize actuators by input signal, voltage, motor type, output motion (rotary/linear) to name a few. This can make searching for actuators and understanding the tech behind them a little challenging at times. For this article, we are going to focus on four common types of electric actuators, and how each type of electric actuator works.

Linear Actuators

Electric linear actuators turn the rotary motion of a motor into linear motion by using a lead screw mechanism. They come in a variety of sizes from tiny micro linear actuators through to larger industrial actuators. They typically consist of a motor, gearbox, control system, lead screw mechanism and external housing.

The simplest electric linear actuators are 2-wire devices that operate by switching the input voltage polarity. More complex actuators can accept other input signals including PWM, DC voltage, current loops or integrate with common or proprietary control systems. The motor turns a lead screw either directly or through a gearbox that allows for modification of the speed/force characteristics. The lead screw drives either a shaft (rod actuators) or a block (track actuators) to which the load is mounted.

Rotary Actuators

A rotary actuator is a mechanical device that uses an electric motor to turn a shaft, valve or other mechanism. It typically consists of an electric motor, gearbox, and control system to facilitate controlled movement. They are often used in industrial settings and are ideal for tasks requiring precise, rotational motion.

The motor shaft typically drives a component with a rotational force, either directly or through a gearbox mechanism. Rotary actuators are commonly used to control valves in liquid and gas systems.

Electromagnetic Actuators

An electromagnetic actuator is a device that generates mechanical motion through the interaction of magnetic fields. It typically consists of a coil or winding, a magnetic core, and a plunger or armature. When an electrical current flows through the coil, it produces a magnetic field that induces motion in the core or armature, enabling the actuator to perform various switching functions in applications like valves, relays, and solenoids. Due to their simplicity, electromagnetic actuators are a good choice for applications where cost and reliability are primary considerations. They’re ideal for quick, consistent actuations that do not require adjustable stroke.

Servo Actuators

A servo actuator is a device that integrates a servo motor with a feedback system to achieve precise control over position, speed, and torque. It operates in a closed-loop system, continuously adjusting its position based on feedback from sensors to maintain the desired position. Servo actuators are widely used in robotics, automation, and various industrial applications requiring accurate and responsive motion control. Servo actuators are often physically similar to rotary or linear actuators, but are functionally different. A servo actuator will always have a minimum of 3 wires, as it requires a signal that is separate from power. A servo actuator is capable of position control and can receive a command to go to a specific position, and then act on that.

Advantages of Electric Actuators

Cost

Electric actuators are typically less expensive to implement than other styles. Hydraulic and pneumatic actuators require expensive control systems for operation. Customizability Electric actuators are highly customizable. Motor voltage, stroke, force, mounts, cable length, limit switches, and other aspects can often be customized by a manufacturer. Custom electric actuators can be a cost-effective way to meet the requirements of your product.

Mobility

Hydraulic and pneumatic actuators require fixed fluid or compressed air systems to operate making it impractical to move them around. Electric actuators just require power, which can be found nearly everywhere and so are more mobile by nature.

Electric Actuator FAQ

Can electric actuators be customized to meet specific requirements?

Yes, an electric actuator manufacturer can work with you to develop a custom electric actuator. Many aspects of an actuator can be customized including stroke, force, input, limit switch position, mounting method, motor voltage and more. For more information on custom electric actuators, check out this page.

What types of motors do electric actuators use?

Electric actuators use one of three motor types: DC, AC or stepper motors.

Can I adjust the speed of an electric actuator?

Yes. How to adjust the speed of an actuator depends on the motor and input on the specific device, but it is possible. For more info on adjusting actuator speed, check out this article.

What is needed to control an electric linear actuator?

This depends on the actuator. DC motor actuators can be controlled with a simple rocker switch. Servo actuators require an arduino, RC receiver or other device capable of outputting a standard servo signal. See the data sheet for the specific device you’re considering for details on how to control it.

What is the duty cycle of an electric actuator

This depends on the actuator, but you can expect duty cycles for DC actuators to start at 20%. Stepper actuators have duty cycles up to 100%. Always check the datasheet for your specific actuator and choose one that is appropriate for your required duty cycle.

Now You Know Electric Actuators Work

In conclusion, delving into the realm of electric actuators unveils a world of mechanical ingenuity that powers our technological landscape. These devices, from linear to rotary and electromagnetic to servo actuators, play diverse roles in industries and applications where controlled motion is paramount. Understanding the basics of electric actuators sheds light on their significance, from their role as the muscle behind various systems to their ability to drive innovation in medical, manufacturing, automotive, and aerospace fields. The advantages of electric actuators, including cost-effectiveness, customizability, and enhanced mobility, underscore their pivotal position in the evolution of automation and motion control technologies.

As Actuonix and the industry navigate the complexities of electric actuators, we witness how their simplicity and reliability contribute to powering the machinery that defines our modern world.