What is a linear motor – Principle

Linear motors are a special class of synchronous brushless servo motors. They work like torque motors, but are opened up and rolled out flat. Through the electromagnetic interaction between a coil assembly (primary part) and a permanent magnet assembly (secondary part), the electrical energy is converted to linear mechanical energy with a high level of efficiency. Other common names for the primary component are motor, moving part, slider or glider, while the secondary part is also called magnetic way or magnet track.

Since linear motors are designed to produce high force at low speeds or even when stationary, the sizing is not based on power but purely on force, contrary to traditional drives.

The moving part of a linear motor is directly coupled to the machine load, saving space, simplifying machine design, eliminating backlash, and removing potential failure sources such as ballscrew systems, couplings, belts, or other mechanical transmissions. Finally, the bandwidth and the stiffness of the motion system are much higher, giving better positional repeatability and accuracy over unlimited travel at higher speeds.

Given that frameless linear motors do not include a housing, bearings, or feedback device, the machine builder is free to select these additional components in order to best fit the application requirements.