A Beginner’s Guide to Electric Actuators

If you’re into electronics, engineering and making things move, you’ll need a good handle on electric actuators. Use this beginner’s guide to electric actuators before you set out to purchase your first actuator.

What is An Actuator?

Before linear electric actuators were around, the only way to make a robot move forward was to use rotary actuators. Linear actuators changed all that. When it comes to electric actuators, you’ve got two main choices: lead screw and ball screw. You’ve really got a ton of choices, like peizo-electric, and there are a ton of innovations happening right now, but for this article, we’ll stick to the basics.

Lead Screw Actuators

Lead screw actuators use a threaded lead screw and a nut to create motion. The gear system runs, turning the screw moving it along the nut.

Here’s a quick diagram to illustrate the idea.

Ball Screw Actuators

They essentially use the same principle with a lead screw and a motor, but instead of using a nut, they use small bearings that run inside the threads. This can change the amount of friction that occurs on the nut and screw.

Either actuator you choose, there are a number of different kinds. These include track actuators, feedback actuators, mini linear actuators high speed actuators and many others. If you can think it up, there’s probably an actuator that can handle it.

The Components

Although electric actuators are simple systems, a lot goes into the making of these devices. Here’s a quick look at the internals of a linear electric actuator.

Controllers

Any actuator you purchase will need a controller. A controller can be a handheld remote, a rocker switch, a foot switch or other types of controls.

Power Source

Of course, you can’t move a thing without a power source. Actuators are moved with either an AC or DC power source, depending on how you’d like to have control.

Accessories

Accessories can be added to your actuators to improve or change performance. Speed controllers can be used for changing speeds and limit switches can change the stroke size just to name a few.

The Specifications

When you get into the selection process, you’ll want to find out how to select the proper actuator for the project. Here are a few starting points.

Force

Force is the load amount that an actuator can push and pull. When you read the specifications, unless it’s otherwise stated, the force quoted is the dynamic force. The dynamic force is the amount of weight that actuator can push. The other force, the static force, is the amount of weight it can handle at rest.

Finding the force required can be as simple as finding out the weight of your entire project. Be careful not to go over the force specifications, or you’ll do some damage to your actuators or to your project.

Speed

Force and speed go together. The more force you have in an actuator, the lower the speed will be. Most actuator specifications have available speeds for certain forces, so you’ll need to take the two into consideration together.

Stroke

The stroke length is the distance the actuator needs to travel. Actuators can have a stroke length as short as an inch or as long as an entire room. The easiest way to determine the stroke length you need is to measure your project from its starting position to its ending position. That’s the amount of stroke length you need.

These are the main three specifications you’ll want to consider, but there are others like voltage, dimensions of the actuator, and accessories. If you really need to find a specific actuator, you might be able to find someone that customizes actuators. There are companies that will customize a single actuator for you.