Ironless linear motor
Schaeffler ULIM ironless linear motors (IDAM)
Ironless U-channel linear motors in six models with up to 1,932 N peak and 669 N continuous force and limit speeds up to 24.2 m/s, for highly dynamic, cog-free motion.
Key specifications
| Voltage (max) | 600 V |
|---|---|
| Peak force (max) | 1,932 N |
| Continuous force (max) | 669 N |
| Linear speed (max) | 24.2 m/s |
| Supply | DC link 60, 160, 300 or 600 V by model |
Summarised in our own words from Schaeffler AG's published data; series maxima, individual models vary. Last checked 2026-10-30. Source 1
Notes on this data
Continuous force at 12 A rating condition (Fc12). Max speed is for the shortest ULIM3-2P.
Specify Motion is not affiliated with Schaeffler AG. Schaeffler and ULIM ironless linear motors (IDAM) are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
Typical applications
Alternatives that meet or exceed these figures
Engineers often come to us with a Schaeffler part number and leave with an alternative that is easier to source, quicker to deliver or a better fit for the machine. These 3 series from our supply network are the closest match on published figures.
U-channel ironless linear motors with zero cogging, six sizes from 3 N to nearly 2 kN continuous, for fast settling precision stages.
| Published maximum | ULIM ironless linear motors (IDAM) | AUM |
|---|---|---|
| Peak force | 1,932 N | 16,200 N meets or exceeds |
| Continuous force | 669 N | 1,980 N meets or exceeds |
| Speed | 24.2 m/s | 5 m/s |
Vacuum-compatible ironless linear motors with high motor constant and zero cogging, six sizes.
| Published maximum | ULIM ironless linear motors (IDAM) | AWM |
|---|---|---|
| Peak force | 1,932 N | 3,845.3 N meets or exceeds |
| Continuous force | 669 N | 769.1 N meets or exceeds |
| Speed | 24.2 m/s | 5 m/s |
Curved (arc-segment) ironless motors for limited-angle or 360-degree rotary motion on large radii, zero cogging and zero attraction force.
View ACR →Figures are the highest published for each series and are not always measured the same way. A higher figure is not automatically a better choice: mounting, duty cycle, feedback, connectors and approvals matter too. An engineer will check the fit against your application before recommending anything.
What an ironless linear motor is
An ironless linear motor, also called a coreless or U-channel linear motor, has a coil assembly with no iron, typically encapsulated in epoxy, moving inside a U-shaped channel lined with magnets on both sides. With no iron in the moving part, there is no cogging and no magnetic attraction between forcer and track. The forcer is light, so acceleration can be very high. Like other linear motors, it drives the load directly and relies on a linear encoder and external guides.
When engineers choose an ironless linear motor
Choose an ironless linear motor for very smooth motion, constant velocity and fast settling with light to moderate loads, such as scanning, metrology, semiconductor and inspection. The trade-offs are force density and heat: without an iron core, continuous force per size is lower and the coil has less thermal mass. The U-channel track is also bulkier and more expensive per metre. For heavy loads or high continuous force, an iron-core design is usually more economical.
How to specify the Schaeffler ULIM ironless linear motors (IDAM)
Send these with your enquiry and an engineer can confirm the right ULIM ironless linear motors (IDAM) variant or an equivalent:
- Peak and continuous force (N)
- Moving mass and payload (kg)
- Velocity ripple or smoothness requirement
- Stroke and speed (mm, m/s)
- Settling time and positioning accuracy (ms, µm)
- Thermal limits and cooling
- Encoder type and resolution
Common mistakes to avoid
- Using peak force for continuous duty and overheating the coil
- Ignoring cable management on a moving coil
- Assuming guides can be lighter without considering stiffness
- Choosing ironless where an iron-core motor would provide more force for less cost
Schaeffler ULIM ironless linear motors (IDAM): frequently asked questions
What is the Schaeffler ULIM ironless linear motors (IDAM)?
Ironless U-channel linear motors in six models with up to 1,932 N peak and 669 N continuous force and limit speeds up to 24.2 m/s, for highly dynamic, cog-free motion. Published series figures include voltage 600 V, peak force 1,932 N, continuous force 669 N, linear speed 24.2 m/s. It is made by Schaeffler AG; Specify Motion can help source it or propose an equivalent.
Who makes the Schaeffler ULIM ironless linear motors (IDAM)?
The Schaeffler ULIM ironless linear motors (IDAM) is made by Schaeffler (Schaeffler AG) and is listed here for engineers comparing options. Specify Motion is not affiliated with Schaeffler AG; brand names are used only to identify the product.
What is the voltage of the Schaeffler ULIM ironless linear motors (IDAM)?
The published series maximum voltage is 600 V. Individual models and sizes in the ULIM ironless linear motors (IDAM) range vary, so check the exact variant against your duty cycle, mounting and environment, or ask our engineers to confirm the right size for you.
Is there an alternative to the Schaeffler ULIM ironless linear motors (IDAM)?
Yes. On published figures, Akribis Systems AUM and Akribis Systems AWM are the closest match from our supply network. An engineer confirms the fit against your application before recommending anything.
Why do ironless linear motors have no cogging?
Cogging comes from iron being attracted to individual magnets as it passes over them. An ironless forcer has no iron in the moving part, so there is nothing to be pulled towards the magnets and the force is smooth. This gives very low velocity ripple, which suits scanning and precise constant-speed motion.
Are ironless linear motors less powerful?
For a given size, ironless motors typically produce less continuous force than iron-core motors and have less thermal mass to absorb heat. Their light forcers allow very high acceleration, so the moving system can still be very dynamic. For heavy loads, iron-core motors are often more economical.
Further reading: How to select a linear motor · Linear actuators
Other ironless linear motor series
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