Load capacity is a critical factor when selecting a linear actuator. Different applications require different load capabilities, and understanding the distinction between static and dynamic load helps ensure proper actuator selection and long-term reliability.
Static vs Dynamic Load in Linear Actuators
Static Load
Static load refers to the force applied to an actuator when it is stationary or holding a position. This includes scenarios such as an actuator supporting a table platform, holding a door, or supporting a display panel in a fixed position.
There are two important performance characteristics to consider when looking at the static loads of your application: the maximum static load and the back-drive force. The maximum static load indicates how much weight an actuator can safely hold without being damaged.
Mounting orientation plays a key role in the static load capabilities, with vertical and horizontal installations having different limitations. The back-drive force capacity is how much applied load an actuator can hold before it begins to extend or retract when no power is applied. It is important to understand what static loads may be present in the application to choose the most suitable actuator.
Dynamic Load
Dynamic load is the force applied to an actuator during its motion. This represents the pushing or pulling force the actuator exerts on an object during extension or retraction, such as when opening doors, lifting platforms, or moving robotic components.
Understanding the applied load during the actuator’s movement is crucial because it determines the actuator's performance characteristics and ultimately its cycle life. Load capacity can vary between push and pull operations, so it is suggested to monitor current draw or applied loads in both directions during application prototyping and actuator evaluation. This will give you the required information to select the best actuator for the application.
Load Measurement
Measuring load requirements accurately is essential for proper actuator selection. The load location relative to the actuator and direction of force must be considered to determine actual forces during operation.
A side load is a force applied perpendicular to the actuator’s direction of travel and should be avoided wherever possible as it can damage the actuator—this is especially true for rod-style actuators.
When measuring loads, proper testing equipment and procedures ensure accurate readings. It is suggested to monitor current draw during prototyping and initial actuator evaluation. This allows you to document expected current draws of the final design and understand what loading is occurring in the application. Current draw of a DC motor is directly related to the applied load on the actuator.
Documentation
Manufacturer specifications provide essential information for actuator selection. Standard documentation includes:
- Maximum static load capacity
- Maximum dynamic load capacity
- Back-drive force
- Test conditions and standards used
- Safety factor recommendations
Installation Requirements
Proper mounting significantly impacts actuator performance. The mounting surface must be able to support both the actuator and the applied loads. Secure attachment points prevent movement during operation. Following manufacturer guidelines for installation ensures optimal performance and prevents premature wear.
Load Testing
Regular load testing helps maintain safe operation. This includes checking mounting points, verifying load conditions haven't changed, and ensuring the actuator operates within specified parameters. Routinely monitoring the current draw on DC motors is a great way to determine if loading characteristics have changed within an application. It can be a quick check that everything is functioning as intended. Document any changes in operating conditions or load requirements.
Maintenance Considerations
Regular inspection of mounting points and connections helps identify potential issues before failure occurs. Keep accurate records of installation parameters and operating conditions. This documentation proves valuable for maintenance scheduling and troubleshooting.
Note: Load ratings vary by manufacturer and model. Always consult specific product documentation for accurate specifications. Contact the manufacturer for guidance on specific application requirements.
Choose the Right Actuator for Your Load Requirements
This guide to static and dynamic load in linear actuators should help you better understand what’s needed for reliable operation. Try our Actuator Selector Tool to find the ideal model for your application, or contact our sales team for personalized help. Actuonix is proud to support engineers, designers, and manufacturers across a wide range of industries.