In this article, I will cover the final type of actuator is an electrical actuator. As most people have worked with pneumatic actuator many people don't know its functionality. Let's learn in deep to store better in our head.
Advancement in motor and its design and its capability to control have bought motor-operated valve in use.
An electrical motor actuator is used mostly for large valve, especially valve which operated with on/off functionality.
Most electrical valve actuators use worm gear set to reduce the high rotational speed to slow rotational speed of the electrical motor to move a large valve mechanism.
As worm screw turns it pushes or pull girth of the worm wheel, resulting in a large gear ratio ( many turns of the screw are required to produce single turns of the wheel).
This slow turning wheel is used to move a sliding stem valve and another extra screw for the rotary valve.
Above image is of an electrical actuator to actuate ball valve assembly using a solenoid control valve.
Some valve comes with hand wheel on it. In case of the power failure, you can actuate with handwheel manually.
Below you can see a ball valve with a handwheel. Here in case of power fail you first have to rotate a lever to engage or disengage the valve mechanism. If you won't move a lever to manual position handwheel not going to move the actuator.
So, you can easily recognize the valve actuator and it's typed by seeing them.
The following figure is of the butterfly used for on/off action. On the left side there is a worm screw and on top of that worm wheel is there which is used to reduce the speed of the actuator.
Electrical actuator require electrical power to operate mostly it uses 3 phase- 440 v supply.
Some electrical type valve has capability of running on a battery pack.
Electrical type of actuators are most accurate and provide very precise control for large amount of the loads.
It requires a separate panel to use power and also can not use in the hazardous area until it is designed to use for such area, which comes with intrinsic safe panel and assembly.