Electric linear actuators can be divided into two main categories: rotary and linear. Before selecting an electric rotary actuator, important considerations include actuator range of motion and torque. Important considerations when selecting linear electric actuators include the length of the valve stem stroke, the number of turns and actuating force. Linear and rotary electric actuators are used in many applications and industries. In the automotive industry, they are used in air conditioning systems and in power door lock systems. Industrial manufacturing operations often require the use of electric actuators as control components for machinery. In agriculture electric actuators are used in many different kinds of farming machinery. Also, in power generation facilities, electric actuators are widely used in wind turbine construction applications.Most electric linear actuators are composed of the same basic components. These components include an electric motor, a screw, a nut and gears in many cases. In an electric actuator, the nut makes possible the transformation of electrical energy to mechanical energy when it rotates along the screw. Using butterfly, ball, and plug valves, electric rotary actuators rotate from open to close. The electromagnetic power from the motor causes the rotation of the components, allowing for many stops during each stroke. A table or a circular shaft can be used as the rotational element in a rotary electric actuator. The power that causes the rotation is called actuator torque, while the full range of motion can be multi-turn, nominal or quarter-turn. In contrast to this, linear electric actuators open and close using globe, pinch, gate, diaphragm or angle valves. Because of their relative compactness, linear actuators are highly favored in applications in which space is limited. All of their working parts and actuation mechanisms often can fit into small areas that would be inaccessible to larger actuation devices. Because they service this unique purpose, the market for linear actuators is likely to continue thriving.
Electric Linear Actuators - Bishop-Wisecarver Corporation