scholarly journals Radial Planar Magnetic Bearing Analysis With Finite Elements Including Rotor Motion and Power Losses

1997 ◽  
Author(s):  
R. D. Rockwell ◽  
P. E. Allaire ◽  
M. E. F. Kasarda
Keyword(s):  
Finite Element ◽  
Magnetic Flux ◽  
Flux Density ◽  
Electric Fields ◽  
Eddy Current ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Magnetic Flux Density ◽  
Magnetic Vector Potential ◽  
Power Losses

No literature is currently available which has evaluated finite element power loss models for magnetic bearings and compared the results to experimental results. In this paper a finite element model of the magnetic and electric fields in magnetic bearings, including the motion of the magnetic material in the rotor, is developed. It evaluates the two dimensional magnetic vector potential, magnetic flux density, electric field, eddy current, and power losses in an example magnetic bearing configuration. Results were obtained for both a solid rotor and a laminated rotor. For a solid rotor, both the magnetic flux density and eddy current plots at high rotational speeds are concentrated at the outer edge of the rotor. The ratio of calculated solid to laminated losses is found to be in the range of measured results by other authors. An effective axial conductivity was employed to model a laminated rotor and compared to experimental loss measurements. The correlation between measured and calculated results is quite good for a range of rotor speeds, magnetic flux density, and air gap thickness.

Rotor Power Losses in Planar Radial Magnetic Bearings — Effects of Number of Stator Poles, Air Gap Thickness, and Magnetic Flux Density

1998 ◽  
Author(s):  
P. E. Allaire ◽  
M. E. F. Kasarda ◽  
L. K. Fujita
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Eddy Current ◽  
Power Loss ◽  
Magnetic Bearing ◽  
Air Gap ◽  
Magnetic Bearings ◽  
Magnetic Flux Density ◽  
Power Losses ◽  
Loss Mechanism

Rotor power losses in magnetic bearings cannot be accurately calculated at this time because of the complexity of the magnetic field distribution and several other effects. The losses are due to eddy currents, hysteresis, and windage. This paper presents measured results in radial magnetic bearing configurations with 8 pole and 16 pole stators and two laminated rotors. Two different air gaps were tested. The rotor power losses were determined by measuring the rundown speed of the rotor after the rotor was spun up to speeds of approximately 30,000 rpm, DN = 2,670,000 mm-rpm, in atmospheric air. The kinetic energy of the rotor is converted to heat by magnetic and air drag power loss mechanisms during the run down. Given past publications and the opinions of researchers in the field, the results were quite unexpected. The measured power losses were found to be nearly independent of the number of poles in the bearing. Also, the overall measured rotor power loss increased significantly as the magnetic flux density increased and also increased significantly as the air gap thickness decreased. A method of separating the hysteresis, eddy current and windage losses is presented. Eddy current effects were found to be the most important loss mechanism in the data analysis, for large clearance bearings. Hysteresis and windage effects did not change much from one configuration to the other.

Rotor Power Losses in Planar Radial Magnetic Bearings—Effects of Number of Stator Poles, Air Gap Thickness, and Magnetic Flux Density

1999 ◽  
Vol 121 (4) ◽  
pp. 691-696 ◽  
Author(s):  
P. E. Allaire ◽  
M. E. F. Kasarda ◽  
L. K. Fujita
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Eddy Current ◽  
Power Loss ◽  
Magnetic Bearing ◽  
Air Gap ◽  
Magnetic Bearings ◽  
Magnetic Flux Density ◽  
Power Losses ◽  
Loss Mechanism

Rotor Power losses in magnetic bearings cannot be accurately calculated at this time because of the complexity of the magnetic field distribution and several other effects. The losses are due to eddy currents, hysteresis, and windage. This paper presents measured results in radial magnetic bearing configurations with eight pole and 16 pole stators and two laminated rotors. Two different air gaps were tested. The rotor power losses were determined by measuring the rundown speed of the rotor after the rotor was spun up to speeds of approximately 30,000 rpm, DN = 2,670,000 mm-rpm, in atmospheric air. The kinetic energy of the rotor is converted to heat by magnetic and air drag power loss mechanisms during the run down. Given past publications and the opinions of researchers in the field, the results were quite unexpected. The measured power losses were found to be nearly independent of the number of poles in the bearing. Also, the overall measured rotor power loss increased significantly as the magnetic flux density increased and also increased significantly as the air gap thickness decreased. A method of separating the hysteresis, eddy current and windage losses is presented. Eddy current effects were found to be the most important loss mechanism in the data analysis, for large clearance bearings. Hysteresis and windage effects did not change much from one configuration to the other.

Flux Density and Air Gap Effects on Rotor Power Loss Measurements in Planar Radial Magnetic Bearings

1997 ◽  
Author(s):  
P. E. Allaire ◽  
M. E. F. Kasarda ◽  
E. H. Maslen ◽  
G. T. Gillies ◽  
L. K. Fujita
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Eddy Current ◽  
Power Loss ◽  
Magnetic Bearing ◽  
Air Gap ◽  
Magnetic Bearings ◽  
Magnetic Flux Density ◽  
Power Losses ◽  
Loss Mechanism

The rotor power losses in magnetic bearings are due to eddy currents, hysteresis, and windage. The influence of air gap magnetic flux density and air gap thickness is not well understood at this time. This paper presents measured results in two magnetic bearing radial configurations with a laminated rotor. The rotor power losses were evaluated by measuring the rundown speed of the rotor, in air, after the rotor was spun up to speeds of approximately 30,000 rpm in atmospheric air. The kinetic energy of the rotor is converted to heat by magnetic and air drag power loss mechanisms during the run down. A method of separating the hysteresis, eddy current and windage losses is presented. Eddy current effects were found to be the most important loss mechanism in the data analysis. Hysteresis and windage effects did not change much from one configuration to the other. The measured rotor power loss increased significantly as the magnetic flux density increased and also increased significantly as the air gap thickness decreased.

scholarly journals Prediction of Inhomogeneous Stress in Metal Structures: A Hybrid Approach Combining Eddy Current Technique and Finite Element Method

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Yating Yu ◽  
Fei Yuan ◽  
Hanchao Li ◽  
Cristian Ulianov ◽  
Guiyun Tian
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Magnetic Flux ◽  
Flux Density ◽  
Eddy Current ◽  
Magnetic Flux Density ◽  
Fe Method ◽  
Metal Structures ◽  
Current Technique ◽  
The Relationship

Concentrated stresses and residual ones are critical for the metal structures’ health, because they can cause microcracks that require emergency maintenance or can result in potential accidents. Therefore, an accurate approach to the measurement of stresses is key for ensuring the health of metal structures. The eddy current technique is an effective approach to detect the stress according to the piezoresistive effect. However, it is limited to detect the surface stress due to the skin effect. In engineering, the stress distribution is inhomogeneous; therefore, to predict the inhomogeneous stress distribution, this paper proposes a nondestructive approach which combines the eddy current technique and finite element (FE) method. The experimental data achieved through the eddy current technique determines the relationship between the applied force and the magnetic flux density, while numerical simulations through the FE method bridge the relationship between the magnetic flux density and the stress distribution in different directions. Therefore, we can predict the inhomogeneous stress nondestructively. As a case study, the applied stress in a three-point-bending simply supported beam was evaluated, and the relative error is less than 8% in the whole beam. This approach can be expected to predict the residual stress in metal structures, such as rail and vehicle structures, if the stress distribution pattern is known.

scholarly journals Finite Element Analysis of the Magnetic Field Distribution in a Magnetic Abrasive Finishing Station and its Impact on the Effects of Finishing Stainless Steel AISI 304L

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 194
Author(s):  
Michał Marczak ◽  
Józef Zawora
Keyword(s):  
Finite Element ◽  
Magnetic Flux ◽  
Flux Density ◽  
Magnetic Flux Density ◽  
Regression Equations ◽  
Element Analysis ◽  
Aisi 304L ◽  
Magnetic Abrasive Finishing ◽  
The Real ◽  
Abrasive Finishing

In this article, we present a numerical model of a magnetic abrasive finishing station, which was analyzed using the finite element method (FEM). The obtained results were compared with the real values measured on an experimental station of our own design. The prepared station had the option of adjusting the magnetic flux density inside the machining gap, the width of which could be changed from 10 to 30 mm. The maximum value of the magnetic flux density inside the air gap was 0.8 T. The real distribution of magnetic flux density in the finishing area was also analyzed. A design of experiment was carried out with the following variables: abrasive grain concentration, width of the machining gap, and process duration. The results are presented in the form of regression equations and characteristics for selected roughness parameters.

scholarly journals A Novel Excitation Approach for Power Transformer Simulation Based on Finite Element Analysis

2021 ◽  
Vol 11 (21) ◽  
pp. 10334
Author(s):  
Wen-Ching Chang ◽  
Cheng-Chien Kuo
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Magnetic Flux ◽  
Flux Density ◽  
Power Transformer ◽  
Core Loss ◽  
Power Transformers ◽  
Magnetic Flux Density ◽  
External Excitation ◽  
Element Method

Power transformers play an indispensable component in AC transmission systems. If the operating condition of a power transformer can be accurately predicted before the equipment is operated, it will help transformer manufacturers to design optimized power transformers. In the optimal design of the power transformer, the design value of the magnetic flux density in the core is important, and it affects the efficiency, cost, and life cycle. Therefore, this paper uses the software of ANSYS Maxwell to solve the instantaneous magnetic flux density distribution, core loss distribution, and total iron loss of the iron core based on the finite element method in the time domain. . In addition, a new external excitation equation is proposed. The new external excitation equation can improve the accuracy of the simulation results and reduce the simulation time. Finally, the three-phase five-limb transformer is developed, and actually measures the local magnetic flux density and total core loss to verify the feasibility of the proposed finite element method of model and simulation parameters.

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