iron core linear motors vs. ironless core linear motors

Comparing Characteristics of Iron Core Linear Motors and Ironless Linear Motors

Linear motors represent a critical component in various industrial and automation applications, offering precise and efficient motion control solutions. Among the diverse array of linear motors available, two main types: iron core and ironless linear motors—stand out for their unique characteristics and suitability for different operational requirements. 

In this blog, we embark on a comprehensive exploration of these two variants, dissecting their advantages, disadvantages, and optimal utilization scenarios.

Iron Core Linear Motors:

Iron core linear motors are distinguished by their construction, featuring copper coil windings wrapped around laminated silicon steel plates. This configuration facilitates maximum force generation through a single-sided magnetic circuit, a hallmark of these motors.

The specialized electromagnetic design inherent in iron core linear motors endows them with several advantageous traits. Notably, they boast high rated thrust, a consequence of their high motor constant (Km), which effectively mitigates thermal losses and minimizes cogging forces.

With their remarkable thrust capabilities, iron core linear motors emerge as the preferred choice for applications involving heavy loads, maintaining rigidity during machining and processing operations.

iron core linear motor

Advantages of Iron Core Linear Motors:

High Thrust Density: Iron core linear motors offer unparalleled thrust density, making them exceptionally adept at handling substantial loads with ease.

Low Cogging Forces: The specialized electromagnetic design minimizes cogging forces, ensuring smooth and precise motion, critical for applications demanding high positional accuracy.

Better Heat Dissipation: Iron core linear motors boast superior heat dissipation due to their predominantly metal composition, acting as a natural heat sink. 

Cost-effective Core Design: The utilization of lamination silicon steel plates in the core design enhances cost efficiency without compromising performance, a significant advantage for budget-conscious projects.

Disadvantages of Iron Core Linear Motors:

High Attractive Forces: Iron core linear motors can generate attractive forces up to 5-13 times the rated thrust, necessitating robust bearing systems capable of withstanding such forces.

Cogging Effects: Cogging effects, inherent in iron core linear motors, can hinder smooth motion and induce velocity fluctuations, potentially impacting precision in certain applications.

Ironless Linear Motors:

In stark contrast, ironless linear motors eschew the traditional ferromagnetic core and slots for coil winding, and rotor with permanent magnets, resulting in a design devoid of cogging effects. 

Ironless linear motors earn their name due to their primary part, akin to a rotary motor’s stator, comprising windings wrapped around laminated steel and embedded in epoxy resin.

This construction method eliminates iron from the primary part, so unlike iron core motors, there are no attractive forces between the primary and secondary parts that can cause cogging and make assembly difficult. 

Furthermore, these motors exhibit lightweight construction and negligible attraction between the coil assembly and the magnetic circuit. These features make ironless linear motors ideally suited for applications necessitating minimal bearing friction, high acceleration on light loads, and consistent performance even at ultra-low speeds.

Their modular magnetic circuit design, comprising two rows of magnets, not only maximizes thrust generation but also facilitates a closed-loop magnetic flux path, enhancing overall efficiency.

ironless core linear motor

Advantages of Ironless Linear Motors:

Absence of Attractive Forces: Ironless linear motors eliminate the presence of attractive forces, simplifying system design and installation, thereby reducing overall complexity.

Zero Cogging Effects: The absence of cogging effects ensures smooth and precise motion, crucial for applications demanding high levels of positional accuracy.

Lightweight Construction: Ironless linear motors are inherently lightweight, offering advantages in applications prioritizing weight reduction and dynamic motion.

Disadvantages of Ironless Linear Motors

Lower Power Density: Ironless linear motors typically exhibit lower power density compared to their iron core counterparts, limiting their suitability for high-load applications.

Increased Magnet Requirement: Achieving comparable performance to iron core motors may necessitate double the amount of magnets, resulting in higher material costs and increased complexity.

Selecting the Right Motor for the Application:

The choice between iron core and ironless linear motors depends largely on the specific requirements of the application:

Ironless Linear Motors: Excelling in applications requiring high-speed, high-repetition positioning on light loads with stringent precision requirements.

Iron Core Linear Motors: Thriving in scenarios demanding high thrust capabilities and rigidity for heavy-duty, high-load applications where precision is not the primary concern.


In conclusion, both iron core and ironless linear motors offer distinct advantages and are tailored to suit specific industrial needs. Engineers can optimize performance and efficiency in their systems by understanding characteristics and applications. This understanding enables them to make well-informed decisions. Ultimately, this drives innovation and progress in linear motion control.


In what applications are linear motor iron lamination stack typically used?

Iron core linear motors are ideal for widespread application in industries requiring robust force generation and high thrust capabilities. Industries commonly employ iron core linear motors in heavy-duty machining and processing equipment, including CNC machines, industrial robots, and material handling systems.

Furthermore, industries utilize motor iron cores in applications demanding precise linear motion. Such as automotive assembly lines, aerospace manufacturing, and medical imaging systems. Their ability to provide substantial thrust and rigidity makes them indispensable in scenarios demanding reliable and powerful linear motion solutions.

In what applications are ironless linear motors typically used?

Ironless motors are ideal for applications necessitating high-speed, high-repetition positioning on light loads with stringent high precision requirements. They are commonly found in semiconductor manufacturing, medical devices, and automation systems.

What are the advantages of linear motors?

Linear motors offer numerous advantages: high acceleration, rapid acceleration and deceleration, strong transmission, steady thrust. They provide unlimited travel length with no performance loss. Additionally, they operate with zero contact, low noise, and brushless design.

Linear motors are suitable for vacuum and harsh environments. They boast high precision and precision maintenance. Linear motors find applications in precision instruments and equipment, achieving step distances of 1 μm accuracy.

What factors should be considered when comparing the characteristics of iron core and ironless linear motors?

When comparing these motors, one should carefully evaluate factors such as thrust density. Evaluators should also consider cogging effects, attractive forces, power density, weight, and precision requirements. These factors help determine the most suitable option for the intended application.

How do iron core and ironless linear motors differ in construction?

Iron core design has coil windings around laminated silicon steel plates, facilitating high thrust density and robust force generation. In contrast, ironless design lack a ferromagnetic core or slots for coil winding, resulting in lightweight construction and zero cogging effects.

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