Motors in semi-hermetic compressor drives are mostly fed from line. Because of good cooling conditions, the motors are heavily loaded and employ a specific rotor structure with "C" bore. In the field ...of semi-hermetic drives, the use of induction motors (IMs) is still dominant, although different motor types with line-starting capabilities, as for example line-start interior permanent magnet synchronous motors (LSIPMSMs), can be used. This work presents the direct performance comparison of a family of commercially available three-phase four-pole IMs for semi-hermetic compressor drives with the equal size prototypes of LSIPMSMs. The motors were rated as 1, 2.5, 3.8, 5.5, 7.5, and 20 hp. The presence of "C" bore in rotor structure can degrade LSIPMSM steady-state performance; therefore, the LSIPMSM designs steady-state performances are evaluated by FEA as well by the experimental method. The motors' dynamic performance is experimentally evaluated as well. The ultimate goal of this study is to reveal the improvement of LSIPMSMs characteristics in comparison to IMs characteristics and to check the possibility for the immediate replacement of existent IMs with LSIPMSMs in the target semi-hermetic compressor application.
In the paper, transient finite-element calculation of the rotational magnetic field is shown. For isotropic material, nonlinear magnetic characteristics of the material are described with ...magnetization curve. For anisotropic material, nonlinear magnetic characteristics of the material are described with magnetization curves for different magnetization directions. For verification, some results of the calculation are compared with the measurement
Passive magnetic bearing Hamler, A.; Goric̆an, V.; Štumberger, B. ...
Journal of magnetism and magnetic materials,
05/2004, Letnik:
272
Journal Article
Recenzirano
The paper presents a special design of a passive magnetic bearing with permanent magnets on the fixed and the rotating part of the bearing. Peculiarity of the presented passive magnetic bearing is ...its ability to take radial and axial loads in both directions by using axially magnetized permanent magnets. A 3D finite element method (3D FEM) is used for analysis of magnetic conditions in the bearing. The performance of the presented magnetic bearing was determined by the Maxwell Stress Method.
The magnetically nonlinear and anisotropic iron core model of a synchronous reluctance motor (SRM) is presented. The iron core model is given by the current-dependent flux linkages and their partial ...derivatives. It is included in a dynamic SRM model and confirmed through the comparison of measured and calculated results in the case of current-controlled linear synchronous reluctance servomotor.
The electromechanical characteristics of induction motors depend on the used stator and rotor slot combination. The correlation between the usage of different stator and rotor slot number ...combinations, magnetic flux density distributions, no-load iron losses and rated load winding over-temperatures for a specific induction motor is presented. The motor's magnetic field was analyzed by traces of the magnetic flux density vector, obtained by FEM. Post-processing of FE magnetic field solution was used for posterior iron loss calculation of the motor iron loss at no-load. The examined motor stator lamination had 36 semi-closed slots and the rotor laminations had 28, 33, 34, 44 and 46 semi-closed slots.
A rotational single sheet tester with square sample (SRSST) is used for the measurement of magnetic properties in rotational and alternating magnetic fields. Two perpendicular measuring coils are ...coiled up, in the middle of the sample, through the holes in the sample. To obtain the proper size of the measuring coils, the homogeneity of the magnetic field and the influence of eddy currents on the homogeneity of the magnetic field distribution in the sample are investigated.
This work deals with the application of the scalar product model to different ferromagnetic materials. Different hysteresis curves and minor loops are measured to examine the behavior of the ...magnetization and to compare it with theoretical calculated curves.
This paper presents a measurement of grain-oriented electrical steel under pure alternating magnetic flux condition at inclination angles from -90 deg to 90 deg with respect to the rolling direction ...(RD). The measurement was carried out using a round rotational single sheet tester. The results show a strong asymmetry of alternating power loss and magnetic field strength with respect to the RD. The alternating power loss depends on the side of the band where the specimen was cut off.
The paper presents a comparison of torque capability and flux-weakening performance of three-phase flux reversal permanent magnet motors with surface and inset permanent magnets. Finite element ...analysis is employed to determine the performance of each motor in BLDC and BLAC operation mode. It is shown that the torque capability and flux-weakening performance of surface or inset permanent magnet configuration is strongly dependent on the stator teeth number/rotor pole number combination.
The paper deals with the detailed analysis of the flux linkages, motor thrust and friction force of the linear synchronous reluctance motor (LSRM). The flux linkages, the motor thrust and the ...friction force are determined experimentally. Their characteristics, given as functions of the position and the direct and the quadrature axis currents, are used to introduce the nonlinear dynamic LSRM model. The agreement between measured and calculated results in the case of the test at blocked primary and in the ease of kinematic control is very good. The presented results show that the motor thrust calculated by using flux linkages should be used with caution especially if an accurate position dependent motor thrust is required.
