Linear electric motors for clients from Germany are under test

Linear electric motor is a type of electric motor that converts electrical energy into linear motion. It’s similar to a traditional rotary motor, but instead of producing a rotational motion, it generates linear movement.

What is a A linear electric motor?

A linear electric motor converts electrical energy directly into straight-line mechanical thrust without rotary-to-linear transmission components. The motor unrolls a rotary machine topology — synchronous, induction, or stepper — into a flat or tubular geometry comprising a primary forcer carrying three-phase windings and a secondary reaction rail carrying permanent magnets or a passive conductor track. Electromagnetic interaction between forcer and rail generates Lorentz force along the travel axis. Peak thrust spans 10N to 50,000N; continuous thrust reaches 5N to 15,000N; maximum velocity achieves 0.1 m/s to 10 m/s; positioning resolution reaches sub-nanometer with linear encoder feedback on closed-loop servo systems.

Linear electric motors are commonly used in various industrial applications where precise and controlled linear motion is required. They offer several advantages over conventional mechanical systems, such as higher accuracy, faster response times, and increased reliability due to their simple design and absence of mechanical transmission elements like gears, belts, or screws.

The basic construction of a linear servo motor consists of a stator and a mover. The stator contains a series of coils that are energized with electric current, creating a magnetic field. The mover, typically a permanent magnet or a set of magnets, is attracted or repelled by the magnetic field, resulting in linear motion along a track or guide.

The movement of the mover is controlled by a feedback mechanism, usually involving position sensors such as encoders or linear scales. These sensors provide precise information about the position and speed of the mover, allowing for accurate control and positioning.

FAQs

1. What distinguishes iron core from ironless linear motor construction?
   Iron core forcers use laminated steel teeth concentrating magnetic flux, generating high thrust density but producing cogging force from tooth-to-magnet attraction — typically 5–15% of peak thrust. Ironless forcers use epoxy-encapsulated copper windings with no steel core, eliminating cogging entirely at the cost of lower thrust density and higher moving mass per newton of force output.
2. How does cogging force affect linear motor positioning performance?
   Cogging force produces periodic thrust ripple as forcer teeth pass over magnet pole transitions. At low velocities, ripple manifests as velocity variation and position hunting. Servo drives compensate using feedforward cogging maps — pre-measured force profiles stored in the drive and subtracted from the current command in real time, reducing effective cogging below 0.5% of peak thrust.
3.  What magnetic attraction force exists between iron core linear motor and magnet rail?
   Iron core forcers generate strong normal attraction force between laminated teeth and permanent magnet rail — typically 3–10 times the rated thrust force. This attraction force preloads the guide rail carriages, increasing system stiffness but raising bearing friction and carriage wear rates. Guide rail and carriage systems must handle this constant perpendicular preload across full travel length without deflection.
4. How does magnet rail pitch affect linear motor thrust ripple?
   Magnet pole pitch determines the spatial frequency of flux density variation along the travel axis. Mismatching forcer winding pitch to magnet pole pitch increases thrust ripple amplitude. Manufacturers optimize pole pitch ratios — typically using fractional slot winding configurations — to distribute ripple harmonics across multiple spatial frequencies, reducing peak ripple magnitude below 2% of continuous thrust on precision-grade motors.
5. What installation parallelism tolerance applies between linear motor forcer and magnet rail?
   Maintain air gap between forcer face and magnet rail surface within ±0.1mm of nominal — typically 0.5mm to 1.0mm total gap. Gap variation above ±0.2mm alters local flux density, producing thrust force non-uniformity along travel. Measure gap with feeler gauges at multiple points across full travel length. Shim the rail mounting surface to below 0.05mm flatness before final fastener torque sequence.

You are welcome to  https://www.youtube.com/@tallmanrobotics to watch our video centre for more projects or visit our website to check other series or load down e-catalogues for further technical data.