To move a specific payload at a predetermined acceleration, speed, trip distance, and accuracy, a linear motor is utilized. All motion technologies aside from linear motor driven use a mechanical drive of some kind to translate rotational motion into linear motion. These motion systems are powered by rack and pinion, belts, or ball screws. All of these drives have a relatively short service life that is largely based on the wear of the mechanical parts that transform rotary motion into linear motion.
Since air serves as the transmission medium and linear motors are virtually frictionless drives with an infinite service life, their primary benefit is the ability to provide linear motion without the need for a mechanical system. We have a wide range of suppliers and manufacturers of Actuator Electric on our website. Extremely high accelerations and speeds are achievable, to the point where traditional drives like ball screws, belts, or rack and pinion will face significant constraints because no mechanical elements are required to achieve linear motion.
It consists of a "secondary" that is typically made up of a steel plate and a copper or aluminum plate, and a "primary" that is made up of a stack of electrical steel laminations and several copper coils powered by a three-phase voltage. A field of eddy currents forms in the secondary conductor when the primary coils are energized, magnetizing the secondary. The primary back EMF and this secondary field will then interact to produce force. Motion will be in a direction perpendicular to the direction of the current and the direction of the field or flux, by Fleming's left-hand rule.
Since the secondary of a linear induction motor doesn't require any permanent magnets, it has the benefit of being extremely inexpensive. Permanent magnets made of NdFeB and SmCo are highly costly. By using extremely common materials for their secondary, linear induction motors remove this supply risk. The availability of drivers for linear induction motors is a drawback when utilizing them, though. Locating drives for linear induction motors is quite challenging, however, locating drives for permanent magnet linear motors is rather simple.
The main of permanent magnet linear synchronous motors (PMLSMs), which are made up of a series of coils installed atop a stack of electrical steel laminations and powered by a three-phase voltage, is substantially the same as that of linear induction motors. The secondary is not the same.
The secondary is made up of permanent magnets set on a steel plate rather than an aluminum or copper plate fixed on a steel plate. As illustrated in the magnetization direction each magnet will alternate concerning the preceding one. Using permanent magnets has the obvious benefit of producing a permanent field in the secondary. As we've seen, an induction motor produces force through the interplay of its primary and secondary fields. However, the secondary field can only be created once the motor air gap creates a field of eddy currents in the secondary. As a result, there will be a "slip" delay and the secondary will move out of phase with the primary voltage that is applied to it.
1. Enhanced machine precision and speed: Direct driving makes high speed and high accuracy possible. Submicron high-precision positioning can be achieved, contingent on the linear encoder's resolution.
2. Equipment structure simplification: It is not necessary to use mechanical linear motion conversion methods like timing belts or ball screws. You can achieve a high degree of stroke length flexibility by extending the magnet rail.
3. Clear and silent apparatus: More silent than a rotary motor system since the linear motion conversion mechanism does not employ noisy moving components like ball screws. Cleaner because sliding parts don't produce dust.
4. Linear slides can be used for a variety of purposes: Configuring a multi-slide system is made simpler by the ability to mount many coils (movers) on the magnet rail.
The primary moves and produces a linear force due to the attraction and repulsive forces between the secondary part's magnets and coils. The force produced is determined by the current's amperage, while the movement's velocity is controlled by the current's rate of change.
Application. Often, high-performance industrial automation equipment is operated by linear motors. They have the advantage of offering any combination of high precision, high velocity, high force, and long travel, which sets them apart from other widely used actuators like a rack and pinion, timing belt, or ball screw.
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