Principle of Opearation of Siemens Linear Motors

The principle of operation of a synchronous linear motor is based on a conductor, through which a current flows. When this conductor is then placed in a permanent magnetic field, a force is exerted on it which causes it to move. The closed-loop control system comprising CNC control, servo controller and sensor system (linear scale) transforms this into a precision positioning drive system.

The motors consist of a primary section (1) and a secondary section (2) with rare-earth magnets. The primary section has fixed dimensions, while the secondary section is made up of individual elements (segments) to suit the traversing range. Through parallel operation of the motors, force and length can be scaled beyond the available spectrum.

The driving force is generated using a traveling electromagnetic field where generally, the primary section is moved with respect to the magnetic secondary section. The primary section is mounted on track-precision linear guides (4) equipped with a linear scales to measure the traversed position (3).