Duty cycle is a function of the on-time operation of the actuator's motor. Following the duty cycle guidelines for your actuator helps ensure that you do not overheat the motor and damage components of the actuator.
You can calculate the duty cycle of your actuator in the following manner:
Duty cycle (%) = (actuator on-time) / (on-time + off-time)
So, if you actuator operates for 15 s. and then rests for 45 s. during a 1 min. cycle, your duty cycle is:
Duty cycle = (15 s.) / (15 s. + 45 s.) = 15 / 60 = 0.25, or 25%
The duty cycles vary per actuator. You can find the ratings in the Thomson Linear Actuator catalog. Some duty cycle ratings also vary based on the loading of the actuator.  This is especially true for our DC actuators. When load is a factor, a chart will be included in the catalog for your reference.
There are other factors that could influence your actuator's duty cycle, such as ambient temperature, loading characteristics, age, etc. However, the guidelines here and in our catalog are a good general reference. If you have further questions about duty cycle, please contact the Thomson Technical Support Team.