Linear Motors

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Selecting a linear motor requires consideration of speeds, torque, load, response time and several other factors .

How to select a Linear Motor for your application

First.. a little background on linear motors.

A linear motor is a lot like the electric drives we described in the video on stepper motors.

Imagine taking that motor, cutting it in half, and unrolling it until it was flat.

The torque force would become a linear force. That’s the concept of a linear drive.

The linear motor has 2 main components – the stationary track, called a platen, and the moving.

Since the principles of linear motors are similar to rotary motors, the controls are also similar to those we covered in the video on servomotors.

Linear motors are used in a wide range of applications, such as medical imaging, medical devices, robotics, factory automation and machine tools:

The main advantage to a linear motor is obvious. They eliminate the belts and pulley or racks and pinions or other rotation-to-translation mechanisms you would need to translate rotary motion to linear motion for applications that require linear motion.

One advantage of eliminating the mechanical transmission components include that there is no backlash. Also the response can be over 100 times faster than a mechanical transmission.

And linear motors can also operate at very high speeds with high precision, typically in the range of 3 meters per second with 1 micron resolution.

Advantages of a linear motor

  • Eliminate rotation to translation mechanisms
  • Zero backlash and fast response
  • High speeds with High precision
  • Fast response

When you are selecting your linear motor, you’ll need to consider first, what speed profile you will need for your load movements. What is the maximum speed? How fast should the load be accelerated? What is the length of the movement you need to achieve, and how long is the rest time? You’ll also have to specify the peak force and the continuous force your application demands.

Once you’ve determined the physical requirements, you’ll need to figure out the temperature of the motor windings. This is where it may be handy to use software or contact the engineering team at the motor distributor.

Even if you carefully specify your motor, the tuning stage may take you a while. You may have to purchase a few samples in different sizes and test them before placing a larger order.