Last revised: January 7, 2025

Electric rotary actuators drive components rotationally via electromagnetic power from a motor. They typically provide control and indexing capabilities to allow multiple position stops along strokes. The rotational element for electric rotary actuators can be either a circular shaft or a table. Circular shafts often include keyways while tables provide a bolt pattern for mounting other components. Both single and double shafts are available. Important dimensions include shaft or table diameter and shaft length or table height. The length of the shaft is measured from the body of the actuator. The table height or thickness does not include the actuator body. With some electric rotary actuators, the angle can be adjusted via screws or other stop adjustments. With other devices, the angle can be adjusted on both ends of the angular stroke. Special features include cushioning to soften stops, position feedback devices such as encoders and potentiometers, and magnetic bands that can be read by a switch.  

Specifications

Performance specifications for electric rotary actuators include supply voltage, repeatability, maximum torque, load capacity, linear stroke, operating temperature, and rotation angle. Supply voltage is the nominal voltage supplied to the motor. Repeatability is the degree to which a position can be duplicated. Maximum torque is the required range of torque output. There are two types of load capacity: axial load capacity and radial load capacity. Axial load capacity is the required axial or thrust load capacity of the output shaft or table. Radial load capacity is the required radial load capacity of the output shaft or table. Linear stroke, another performance specification, is the travel distance between the fully retracted and fully extended rod positions. Operating temperature is a full-required range. Rotation angle is the degree to which the actuator can rotate before reaching its travel limit. Typically, electric rotary actuators provide a maximum rotation angle of 45°, 90°, 135°, 180°, 225°, 270°, 315°, or 360°. 

Applications

There are a variety of applications for electric rotary actuators. Some devices are designed for semiconductor manufacturing operations. Others are suitable for laboratory or medical use. Electric rotary actuators are used in the electric power industry, high-power switching gears, and packaging applications. In the automotive industry, manual and electric devices are used in car seats. Chrome-plated steel components are suitable for dry, indoor applications. Hybrid devices that use molded thermoplastic threads inside a metallic shell can extend actuator life. For applications that require rotational motion less than one revolution, electric rotary actuators can mount right at the equipment joint without taking up space with long stroke lengths.

Electric Rotary Actuators FAQs

What are the key advantages of using electric rotary actuators over pneumatic or hydraulic options in engineering applications?

Electric rotary actuators offer several key advantages over pneumatic and hydraulic options in engineering applications. Here are some of the main benefits:

Energy Efficiency

Electric actuators generally operate with an efficiency range of 75% to 80%, which is significantly higher than pneumatics (10% to 25%) and hydraulics (40% to 55%).

Control and Precision

Electric actuators provide superior control capabilities, including high precision in position, velocity, acceleration, and deceleration. This allows for smooth and precise motion control, which is often required in complex engineering applications.

They offer high accuracy and repeatability, with setups that can be easily reprogrammed and networked for various applications.

Safety and Reliability

Electric actuators are known for their higher reliability and lower maintenance requirements compared to hydraulic systems, which can suffer from seal wear, pressure drops, and leaks.

They eliminate the risk of hazardous fluid leaks, making them environmentally safer and reducing maintenance needs.

Quiet and Compact Operation

Electric actuators are quieter than their pneumatic and hydraulic counterparts, which is beneficial in environments where noise reduction is important.

Adaptability and Flexibility

They can be easily integrated with control systems for complex configurations, allowing for synchronized movement of multiple actuators and easy adjustments to motion profiles.

Temperature and Environmental Resistance

Electric actuators are less affected by temperature variations and do not overheat easily, making them suitable for a wide range of environmental conditions.

These advantages make electric rotary actuators a preferred choice in many engineering applications, especially where precision, efficiency, and safety are critical.

What is the energy efficiency of electric actuators compared to other types?

Electric actuators are known for their superior energy efficiency compared to pneumatic and hydraulic actuators. Here are some key points regarding their energy efficiency:

Efficiency Range

Electric actuators generally operate within an efficiency range of 75% to 80%, which is significantly higher than that of pneumatic actuators (10% to 25%) and hydraulic actuators (40% to 55%).

Energy Consumption

Electric actuators only use current in the drive motors when needed. They consume very little or no current to maintain their position when at rest, which contributes to their energy efficiency.

In contrast, fluid-powered actuators, such as pneumatic and hydraulic systems, require a constant supply of pressurized fluid, leading to less efficient power usage.

Standby Efficiency

Electric actuators do not require current for position-holding during standby, which further enhances their energy efficiency compared to fluid-powered systems.

These factors make electric actuators a more energy-efficient choice in many engineering applications, particularly where energy conservation is a priority.

What is the control and precision advantages of electric actuators?

Electric actuators offer significant control and precision advantages over pneumatic and hydraulic actuators. Here are some key points:

Superior Control Capabilities

Electric actuators provide high control over position, velocity, acceleration, and deceleration. This allows for smooth and precise motion control, which is essential in complex engineering applications.

They enable "soft stop" technology, meaning they can glide into position smoothly without abrupt stops or lurches, which is beneficial in applications where vibrations and disruptive movements are not acceptable.

High Accuracy and Repeatability

Electric actuators offer exceptional accuracy and repeatability. For example, they can achieve positioning accuracy within +/- 0.000315 inches and repeatability of less than 0.0000394 inches.

Their setups are scalable and can be easily reprogrammed, allowing for quick adjustments and network integration for various applications.

Flexibility and Adaptability

Electric actuators can be integrated with control systems for complex configurations, allowing for synchronized movement of multiple actuators and easy adjustments to motion profiles.

They provide complete control of motion profiles and can include encoders to control velocity, position, torque, and applied force.

Reliability and Maintenance

Electric actuators are known for their reliability and lower maintenance requirements compared to hydraulic systems, which can suffer from seal wear, pressure drops, and leaks.

They offer immediate feedback for diagnostics and maintenance, enhancing their reliability and ease of use.

These advantages make electric actuators a preferred choice in many engineering applications where precision, control, and adaptability are critical.

What are the maintenance requirements for electric actuators?

Electric actuators are known for their reliability and lower maintenance requirements compared to other types of actuators, such as hydraulic systems. Here are some insights into their maintenance requirements:

Electric actuators generally require less maintenance than hydraulic systems, which can suffer from issues like seal wear, pressure drops, and leaks.

Since electric actuators do not use fluids, they eliminate the risk of hazardous fluid leaks, which reduces maintenance needs and environmental hazards.

Electric actuators offer immediate feedback for diagnostics, which can help in identifying and addressing maintenance issues promptly.

They are designed with easy and economical replaceable parts, which simplifies maintenance and extends the life of the actuator.

These factors contribute to the overall lower maintenance requirements of electric actuators, making them a reliable choice in many engineering applications.

What is the adaptability of electric actuators in different applications?

Electric actuators are highly adaptable in various engineering applications due to several key features and capabilities. Here are some insights into their adaptability:

Motion Control Flexibility

Electric actuators offer exceptional motion control capabilities, allowing for precise control over position, velocity, acceleration, and deceleration. This flexibility enables them to be used in complex configurations where synchronized movement of multiple actuators is required.

Programmability and Integration

They can be easily integrated with control systems and reprogrammed for different applications. This adaptability allows for quick adjustments to motion profiles and the ability to network multiple actuators for coordinated operations.

Environmental Suitability

Electric actuators are designed to operate in various environmental conditions. They are less affected by temperature variations and do not overheat easily, making them suitable for rugged environments. Additionally, they do not leak hazardous fluids, which enhances their adaptability in environmentally sensitive applications.

Precision and Repeatability

The high precision and repeatability of electric actuators make them suitable for applications requiring exact positioning and consistent performance. This is particularly important in industries such as aerospace, where precision is critical.

Soft Stop Technology

Electric actuators can incorporate "soft stop" technology, allowing them to glide smoothly into position without abrupt stops. This feature is beneficial in applications where minimizing vibrations and disruptive movements is essential.

These characteristics make electric actuators a versatile choice across a wide range of engineering applications, from industrial automation to aerospace and beyond.

What are the environmental benefits of using electric actuators?

Electric actuators offer several environmental benefits compared to pneumatic and hydraulic actuators. Here are some key points:

Elimination of Fluid Leaks

Electric actuators do not use hydraulic or pneumatic fluids, which eliminates the risk of hazardous fluid leaks. This reduces environmental hazards and the potential for contamination.

Energy Efficiency

Electric actuators operate with a higher energy efficiency range (75% to 80%) compared to pneumatic (10% to 25%) and hydraulic systems (40% to 55%). This efficiency means less energy consumption and a smaller carbon footprint.

Reduced Noise Pollution

They are quieter than pneumatic and hydraulic systems, which helps in reducing noise pollution in environments where noise levels are a concern.

Adaptability to Environmental Conditions

Electric actuators are less affected by temperature variations and do not overheat easily, making them suitable for a wide range of environmental conditions without the need for additional cooling systems.

These environmental benefits make electric actuators a more sustainable choice in many engineering applications, contributing to reduced environmental impact and improved workplace safety.

Electric Rotary Actuators Media Gallery

References

Electronics360—Pros and Cons of Pneumatic, Hydraulic, and Electric Actuation

GlobalSpec—Fluid vs. electric actuators: What's the better technology?

GlobalSpec—Why Electro-mechanical Actuators are Best for Your Aerospace Application