In determining the right stepper motor linear actuator for a specific application it is necessary to understand stroke length. The stroke length allows the device to handle short or long operational distances. Most, but not all, stepper actuators have a stroke length that allows the actuator to move a specific amount. For example, a small actuator could move a curtain for a window, while a large actuator could move a curtain for a movie screen. As a result, a longer stroke length will increase the price of a linear actuator. Extra length is rarely required, so users should select stepper actuators that exactly fit the application.
Understanding the duty cycle, the elapsed time between operations, will provide a reasonable approximation of the expected lifetime of a stepper actuator. The duty cycle can be based on units of hours per day, minutes per hour, or strokes per minute. By managing the duty cycle one can increase the lifetime and the necessary maintenance required for the stepper actuator.
One of the criteria for selecting a stepper actuator is to identify the amount of force required of the application. Defining the load required for the application can help identify the proper size and capabilities of the stepper actuator. The orientation also plays a key role in selecting the proper stepper actuator.
IMPORTANT NOTE: With a stepper actuator in a horizontal position, the overall load capabilities must compensate for the frictional force. With a stepper actuator in a vertical position, the load necessary is that of the weight due to the gravitational force.
Mechanical Power: The necessary requirement in calculating mechanical power is based on the linear force required to move the load multiplied by the speed at which the load will be moved.
Electrical Power: The electrical power is obtained through performance graphs illustrating force vs. speed and force vs. current, both of which are good representations of the performance of a stepper linear actuator. The performance graphs are specific to each specific stepper actuator model.