Most people involved in any kind of industrial application today have heard of actuators, but have you wondered how these control units came into being? In reality, actuators are all around us but taking this knowledge and turning it into sophisticated control units like a Eurotherm controller is a process which has evolved over many years. Let’s take a closer look at the actuator, where it came from and where it is headed in the future.
Energy Conversion
Actuators change energy into motion and can also apply force. For example, if you apply electric energy to a coil of wire with a movable iron core, you have a basic solenoid. Electricity turns the iron into a magnet and it is attracted to another source of iron, this can be used to throw switches, engage gears, unlock doors and many other functions. Electric motors are also actuators. Relays are sometimes controlled by actuators and they are used to open and close circuits automatically. Actuators see many types of industrial applications.
Linear motion is only kind of motion which can be created by an actuator. For example, if you place a rod on a flywheel, you can create a rotary motion and by using a crankshaft, you create up and down motion. So what does all this have to do with the Eurotherm controller?
Actuators can be mechanical, electric, hydraulic, thermal and many other types. Eurotherm actuators are often used for proportioning and positioning components like dampers and fuel valves. Some use a spring return method while others do not.
Spring Return
A Eurotherm spring return actuator is used to operate two position dampers. It contains a crankshaft which is gear driven by an oil submerged shaded pole electric motor. The unit is completely sealed in its aluminum case for long life service and minimal maintenance requirements. These actuators are often used for on/off control. A spring return mechanism works as a manual fail-safe and will either close or open the actuator when power is lost.
Some actuators are listed as non spring return and these are meant to stay in their position when power is lost. In some cases, this is what you want. However, there is a third option for actuators and it is called an electronic fail-safe device. This type of mechanism utilizes power from a capacitor to open or close the mechanism after power has been lost.
This gives you a basic idea of how equipment like the Eurotherm controller works. For help with choosing the best actuator for your business needs, see your industrial controls distributor.
