Key Takeaways
- Understand what linear actuator duty cycle means and how to calculate it.
- Learn how load, speed, stroke, and cycle frequency affect actuator selection.
- Understand the risks of exceeding the rated duty cycle.
- Learn how to match an actuator’s duty cycle with your application requirements.
A linear actuator may need to move a load only a few times per hour—or operate repeatedly throughout the day. That difference matters. Choosing an actuator based only on force and stroke length can lead to performance problems if the actuator is expected to run more often than its design allows.
Understanding linear actuator duty cycle helps determine whether a particular actuator is suited to the actual operating pattern of an application.
What Does Duty Cycle Mean?
Duty cycle describes how much time an actuator operates compared with the total time in one complete operating cycle.
The basic calculation is:
Duty Cycle (%) = Operating Time/Active Time ÷ Total Cycle Time × 100
For example, if an actuator runs for 20 seconds and then remains idle for 40 seconds, the complete cycle is 60 seconds.
20 ÷ 60 × 100 = 33.3% duty cycle
This calculation provides a useful starting point, but the actuator’s published duty-cycle rating should always be considered as part of the selection process.
Duty cycle may also be specified over a particular reference period, such as 10 minutes. For example, a 20% duty cycle may indicate that the actuator can operate for a specified portion of that period before requiring rest. Because duty-cycle ratings vary by actuator, always check the manufacturer’s specifications for the maximum run time and required rest period.
Why Duty Cycle Matters
Every time an actuator operates, its motor and mechanical components generate heat and experience wear. Frequent operation gives the system less time to cool between cycles.
An actuator that works well for occasional positioning may not be suitable for an application requiring continuous repetitive movement.
This is especially important in automated equipment, material-handling systems, adjustable machinery, and outdoor equipment where the actuator may be expected to perform the same movement thousands of times.
Operating an actuator beyond its rated duty cycle can cause excessive heat, reduced performance, accelerated component wear, or thermal shutdown. Repeated overheating may also shorten the actuator’s service life.
Intermittent vs. Continuous Duty
Many standard linear actuators are designed for intermittent operation, meaning they operate for a period and then require time to cool. Applications involving frequent or sustained movement may require an actuator designed for a higher or continuous-duty application. Always check the manufacturer’s rated operating limits before selecting a model.
Look Beyond Runtime
Duty cycle is only one part of actuator selection. The required workload should be considered alongside:
- Load: How much force must the actuator move or hold?
- Stroke: How far does it need to travel?
- Speed: How quickly must the movement occur?
- Cycle frequency: How often will the actuator operate?
- Environment: Will it be exposed to heat, moisture, dust, or outdoor conditions?
- Installation: How will the actuator be mounted and aligned?
For example, an actuator operating under a moderate load may handle a demanding cycle differently from one moving a much heavier load at high speed.
Understanding the available linear actuator configurations can make it easier to compare these requirements before selecting a model.
How Load and Speed Affect Duty Cycle
Load and speed can affect how much heat an actuator generates during operation. Higher loads or speeds may increase motor demand, especially during frequent repetitive movement.
For this reason, force, speed, stroke, and duty cycle should be evaluated together rather than selecting an actuator based on only one specification.
How to Match an Actuator to the Application
Start by documenting the actual movement pattern rather than estimating how frequently the actuator might operate.
Record how long the actuator runs, how long it rests, how many cycles occur per hour or day, and what load it moves during each cycle.
Then compare those requirements with the manufacturer’s specifications.
If the application involves outdoor positioning or repeated movement, environmental conditions should also be included in the evaluation. Solar equipment, for instance, may require actuators designed specifically for tracking applications. Solar tracking actuators are built around the movement requirements associated with solar positioning systems.
The goal is not simply to find an actuator with enough force. It is to select one that can consistently handle the complete operating pattern.
Before making a final selection, confirm:
- Required force and stroke
- Operating speed
- Cycles per hour or day
- Maximum continuous run time
- Required rest time
- Operating temperature and environment
- Manufacturer’s rated duty cycle
Comparing these requirements with the actuator’s specifications helps ensure the selected model can handle the complete operating pattern.
When a Standard Actuator Isn’t Enough
Some applications have an unusual combination of load, speed, stroke, mounting limitations, and operating frequency. In these situations, choosing the closest standard model may not provide the desired performance.
A customized configuration can allow the actuator to be designed around the actual mechanical requirements instead of forcing the application to fit a standard specification. Custom actuator design can be useful when the application requires a specific combination of performance and mechanical requirements.
Choosing for Long-Term Performance
Selecting a linear actuator is about more than finding the required force and stroke. The actuator also needs to match how often it will operate, how long each cycle lasts, and the conditions in which it will work.
By calculating the expected duty cycle and comparing it with the actuator’s rated operating limits, you can narrow down the options more confidently. This helps ensure the actuator is suited to the application’s actual workload rather than simply meeting its basic movement requirements.
For systems with frequent or repetitive movement, considering duty cycle early in the design process can help support consistent performance and avoid selecting an actuator that is undersized for the job.