An electric linear actuator is a piece of equipment that transforms the rotary motion of a motor into linear motion. It can be integrated into any equipment to push, pull, lift, lower, position, or rotate a load.
Choosing the right electric actuator is the key to any successful automation project. There are many models of parallel, L-shaped, parallel motor actuators that can be employed in many applications.
Each need corresponds to a unique project.
In order to choose the proper actuator, the application and its technical limitations must be taken into account:
• Duty cycle
1. Load requirement
In the choice of the actuator, a determining factor is a load it must withstand. And will define its various components such as motor, nuts, threads, gears, ball bearings, etc.
It is important and essential to determine in which direction the actuator should act? For example: pull, push, vertical or horizontal movement, and over what length?
It will also depend on the diameter of the internal and external tubes of the actuator.
All of the above factors influence the actuator’s capability to lift loads. Also, they will have an impact on its strength.
2. Speed requirement
The desired speed is a fundamental criterion in the choice of the actuator.
Not all materials or mechanisms are suitable with high speeds. High speed with high load can cause premature actuator wear and impact its life.
Hence, each and every device has a speed and a load that must not be surpassed to protect it from material damage. This speed depends, among other things, on the thread and the characteristics of the motor.
3. Duty cycle
The duty cycle defines the relationship between a device’s run time and standby time. It varies considerably from one application to another. The duty cycle is a determining factor in the choice of the actuator, its materials, and its mechanisms. It gives the equipment optimal life and limits the rapid wear of mechanical parts or possible overheating.
Motors, for example in parallel configurations driving the electrical actuators, with their spur gears, withstand a higher duty cycle and can have a higher number of cycles.
4. Availability of Space around
The choice of the actuator is also based on the space available in the system.
In addition to load, travel, and speed, it is important to consider whether the actuator will have to operate in a restricted space if there are any restrictions in terms of space requirements to allow its integration into the application.
For example, parallel electric actuators, because the motor is in parallel with the screw, are more compact and therefore ideal for restricted installation spaces. The size of an actuator hinge on the mounting or installation configuration (inline, L-shaped, or parallel motor).
5. Considerations of Environment
The environment in which the equipment will operate is a determining parameter in selecting the suitable electric actuator.
• Does the equipment work indoors or outdoors?
• Are you subject to dust, solid contaminants, or moisture?
• Do you have to deal with an intensive cleaning with detergents or high-pressure cleaning?
Depending on environmental needs, the materials used and the protection indices (PI) used will not be the same. Does it require a quiet operation? L-shaped electric actuators, for example, thanks to their plastic helical gears, provide a quieter movement, ideal for medical or household equipment.
Everything is variable, everything is adaptable.
The choice of a type of electric actuator depends on many parameters. It is important to choose a linear actuator that can meet the requirements of an application.
Each application has a list of essential requirements to choose the right electric actuator. However, the budget is also taken into account in the constitution of a project.
Author: PSS Bapu Rao