There are different linear actuators *e.g*. pneumatic, hydraulic, piezoelectric, electrostatic, electromagnetic and hybrid ones. The electromagnetic ones are lately most popular. They characterize high stroke, quite high force, good dynamic properties and relatively high resolution [1]. A special case are active magnetic bearing actuators, which are characterized by high precision and very good dynamics [2, 3].

To provide proper power for the electromagnetic actuators, the controlled power system have been proposed. For example, linear reluctance motors (LRM) [4] can be controlled by electronic systems. The simple controlled bridge improves the parameters of the LRM, and enables the tracking of the mover location. Also there are number of pulse-width modulation (PWM) circuits to obtain a variable current at the motor terminals with dc-feed.

To take the advantages of all opportunities mentioned above, all power loss should be taken into account in the designing of a new construction. However, the losses in the actuator mover with permanent magnets (PM’s) separated by ferromagnetic rings, are much lower than those in its stator. That is why the former ones may be negligible as well. However, the comparison should be supported by tests.

The eddy current losses in the linear actuator were calculated in [5]. The permanent magnets actuator was equipped with stator made from Somaloy. However, the results have been given without measurement tests.

In [6], the eddy current losses have been included by a semi-empirical formula involving the total losses after axial cutting in the stator magnetic circuit. In [7], the total losses have been calculated using some analytical expressions in each element of the discretization mesh.

In all papers mentioned above the losses have been calculated for steady-states. However, this state of actuator operation practically exists only in some cases, *e.g*. actuator with blocked mover. In all investigations the hysteresis and eddy current losses have been included as the total ones. There is no paper about linear actuators, where the hysteresis losses would have been included using the advanced models of hysteresis (Preisach or Jiles-Atherton’s models). Only for the rotary orientated field the core losses have been divided into hysteresis loss and eddy current ones [8, 9, 10].

The power losses strongly heat the linear machine. To determine the maximum values of the current intensity and the thrust, they should be calculated as exactly as possible. In the paper an analysis of eddy current losses for a 5-phase permanent magnet tubular linear actuator (TLA) has been studied [11]. The actuator construction has been developed in Department of Electrical Engineering and Mechatronics at Opole University of Technology.

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