Electric Actuators – The Next Trend in Automation
Published on : Tuesday 01-08-2023
Satisfying the demand for linear and rotary automated movement, the electric actuator is the new automation trend.
What is an actuator?
Actuators are a common part of industrial mechanics and everyday life. To put it simply, an actuator is a device that makes a component move or operate tasks.
There are two types of actuators: linear and rotary. For mechanics that require a forward-backward movement, a linear actuator moves in this direction on a straightforward plane. For an operation that involves circular motion, a rotary valve is used.
Actuators can have manual functionality (operated by a hand wheel) that happens alongside the energy-powered automatic operation. To power the actuators, there are three types of energy sources: electrical, hydraulic, and pneumatic.
An electric actuator is a mechanical device used to convert electricity into kinetic energy in either a single linear or rotary motion. It automates the damper or valve in order to increase process efficiency and complexity. Designs for electric actuators are based on the specific tasks they accomplish within the processes for which they’re intended, and they can vary in both dimension and size.
There are now more applications for electric actuators due to the movement toward massively increased decentralisation taking place in automation technology. New process controllers can now be equipped on last-generation electric actuators, which make it simpler to meet recently updated automation standards.
How do electric actuators work?
An electric motor will create rotary motion as the spindle, or rotor, rotates. The motor spindle is directly coupled to a helical screw, via the drive shaft, which in turn rotates in a ball screw nut. As the spindle rotates the ball screw nut is driven forwards, or backwards, along the helical screw.
A hollow piston rod is attached to the ball screw nut and this creates the linear motion out of, or into the linear actuator as the motor rotates clockwise or anti-clockwise.
The motor is controlled by an electric drive, which allows the rotation speed to be varied and, hence, the linear speed of the actuator. A feedback mechanism gives positional information and the linear actuator can be programmed to move to a certain position, stop and then move on, or return to its rest position.
The power of the motor will determine the torque that can be generated and hence the force that can be put to useful motion through the actuator.
Benefits of electric actuators
Easy integration: Electric actuators are much easier to integrate than hydraulic or pneumatic actuators. Electric actuators come with programmable controllers and microprocessors for the management of the operation of most modern industrial machinery.
Precision levels: Electric actuators offer high levels of precision in the control of motion. This is due to the enabling of the torque, speed, and force that they do to modify at different stages during motion.
Safety and convenience: These types of actuators are not susceptible to contamination or leakages like their counterparts. Therefore, they are considered to be cleaner, safer, and more convenient options.
Costs less: These types of actuators are more economical in the long run than other actuators. Electric actuators need less maintenance, are easy to operate and install and are rugged. They also last longer and are reliable when used in different environmental conditions.
What electric actuator can work for?
Electrical actuators can work for a wide range of applications, including industrial ball valves, where precise and reliable mechanical motion control is required. Some of the common applications of electrical actuators are:
i. Industrial automation: Electrical actuators are used in various industrial machines and processes, such as conveyor systems, packaging machines, and assembly lines, to control the movement of components and products.
ii. Aerospace and defence: Electrical actuators are used in aircraft and spacecraft systems, such as landing gear, flaps, and control surfaces, to provide precise and reliable control of motion.
iii. Automotive: Electrical actuators are used in various automotive systems, such as power windows, door locks, and seats, to provide comfortable and convenient control of motion.
iv. Robotics: Electrical actuators are used in various robotic systems, such as robot arms and grippers, to provide precise and flexible control of motion.
v. Medical devices: Electrical actuators, such as surgical robots and prosthetic limbs, are used in various medical devices to provide precise and reliable motion control.
vi. Consumer products: Electrical actuators are used in various consumer products, such as home appliances, toys, and electronics, to provide convenient and user-friendly motion control.
How do I select an electric actuator?
The actuator will be required for an application requiring force. In a pneumatic linear actuator, the force is created by pressure acting on the surface area of a piston. In electric actuators, the force is generated from the torque capability of the motor. The load to be moved, any frictional forces of a surface and the angle of elevation, or declination, of the load will all be critical parameters to consider.
For pneumatic actuators, the load will be required to move a certain distance which determines the stroke of the actuator. The same is true for an electric actuator with some subtle differences. To protect against over-run, the 'usable' stroke is the maximum stroke less than four times the pitch of the helical screw. An electric actuator may be used for a number of positions; therefore, the stroke required will need to take account of the total movement. Different screw pitches are available, dependent on bore, allowing component combinations to meet many application requirements.
It is also useful to consider when an electric actuator would be preferable to a pneumatic solution. In a situation where a compressed air supply is not available, electric is the only alternative (if hydraulic solutions also are not available).
A key advantage of electric linear actuators is the requirement for multiple positions in an application. Other advantages are: higher axial force; high accuracy; low noise; flexibility through control characteristics; load stiffness and overall lower operating costs.
Durga Mechatronics Pvt Ltd, Mumbai.
www.durgamechatronics.com