Linear motors

Traditional rotary motors convert electrical energy into rotational torque, while linear motors convert electrical energy into linear kinetic energy. Compared with lead screws that also move linearly, linear motors have the advantage of not being limited by length. The interior of a rotary motor can be divided into a stator and a rotor, while the interior of a linear motor can be divided into a stator and a mover. Linear motors are directly driven and do not need to be transmitted through other components. In the absence of contact, there is less mechanical wear. It has high efficiency, low noise, and long life. Since there is no centrifugal force in linear motion, the speed limit is relatively generous. Currently, linear motors are mainly used in fast and high-precision positioning systems, transportation fields, etc. Linear motors can be divided into two categories: linear induction motors and linear synchronous motors.

Linear Induction Motor

After the armature winding on the iron core in the LIM is supplied with three-phase electricity, the conductive flat plate on the secondary side induces an eddy current, and an opposite magnetic field is generated by Cold's law. The two magnetic fields interact to generate thrust. , but the design and motor control of LIM are more complex, the air gap is large and the power factor is low, and the external dimensions are larger than linear synchronous motors of the same specifications. It is suitable for long-distance transportation and large-load applications such as mechanical conveyor belts. , crane material transportation, high-speed maglev train, etc.

Linear Synchronous Motor

LSM can be divided into two parts. The first part is the armature winding that generates an alternating magnetic field. The second part is an electromagnet or permanent magnet that generates a fixed magnetic field. The armature winding on the iron core controls the current through the driver to generate a magnetic field with linear mobility, which interacts with the magnetic field of the permanent magnet to achieve the effect of linear motion. LSM on the market can be divided into iron core type and iron coreless type:

With iron core type:

After the coil is energized, the iron core guides the magnetic flux and the magnetic field of the permanent magnet can generate a large thrust. However, when there is no electricity, the motor will generate a sudden force. The heat on the coil can be dissipated through the iron core, which is suitable for In high-load applications, such as laser processing machines, cutting machines, semiconductor equipment, etc.

Without iron core type:

The stator of the coreless motor is usually made into a U-shaped groove. The motor is light in weight and can produce faster acceleration. There is no coercion force and there is no adsorption force between the stator and the mover. It is easy to assemble and is suitable for high-speed and light-load applications. , such as: dust-free environment automation equipment, optical inspection equipment, scanning electron microscope equipment, etc.