Ironcore Linear Motors

It is the force the motor can generate beyond the saturation point, in the non-linear region of the motor’s force constant. Under this condition, the effective force constant is 26% lower than the catalog value. This parameter applies only to iron core motors. Since the efficiency of current-to-force conversion decreases, the windings heat up more quickly. At ultimate force, the temperature rise is 10 K/s or 20 K/s, depending on the motor series.

In iron core motors, peak force is the force generated immediately beyond the saturation point of the motor’s force constant. Under this condition, the effective force constant is 14% lower than the catalog value. The windings heat up at a rate of 6 or 20 K/s, depending on the motor series. Ironless motors, on the other hand, do not have a force constant saturation point. In this case, peak force is determined by the maximum allowable thermal expansion of the winding material. For these motors, the temperature rise is 20 K/s.

The motor constant represents the ratio between the force generated (expressed in Newtons) and the power dissipated as heat (expressed in Watts), and is indicated in N²/W. A higher constant value indicates that the motor generates the same force while dissipating less heat, making it more thermally efficient. The constant value decreases as winding temperature increases, due to the rise in phase-to-phase electrical resistance (Rph-ph).

Formula: S = K² / (3 × Rph-ph)

Permanent magnets exert an attractive force on all ferromagnetic materials. In iron core linear motors, this characteristic generates the so-called cogging effect. The iron core tends to settle into certain preferential positions relative to the magnets. To maintain motion, the motor must therefore continuously vary its thrust force to overcome these positions. The result is a less smooth motion compared to that of an ironless linear motor, comparable to the sensation of driving on a road with an uneven surface.

Thanks to their high continuous force and low thermal dissipation, Iron Core linear motors are particularly suited to applications such as machine tools, laser cutting machines, waterjet cutting machines, and industrial automation. The low-cogging design developed by Tecnotion also makes them suitable for large-format printing machines, where precision and smoothness of motion are essential requirements.

Iron Core linear motors have a small air gap between the primary and secondary parts. This results in low magnetic reluctance and high magnetic flux density, enabling very high continuous forces. In addition, their structure facilitates heat transfer from the lamination stack to the machine structure, ensuring effective thermal management. As a result, the risk of overheating is generally lower than in ironless linear motors, making Iron Core motors particularly suited to applications requiring high continuous performance.