Theoretical investigation of the eddy current loss in thin ferromagnetic plates due to saturation

1963 ◽  
Vol 274 (1357) ◽  
pp. 187-194 ◽  
Keyword(s):  
Differential Equation ◽  
Boundary Condition ◽  
Partial Differential Equation ◽  
Power Factor ◽  
Eddy Current ◽  
Eddy Current Loss ◽  
Current Loss ◽  
Ferromagnetic Plate ◽  
Magnetizing Force ◽  
Sinusoidal Surface

An analytical method is developed for the solution of the partial differential equation of the form ∂ 2 H ∂ z 2 = ( μ ρ ) ∂ ∂ t ( H − ε H 3 ) ɛ being small, H being a function of z and t , for the boundary condition that at the surfaces, z = ± a , either H or d H /d z varies harmonically with respect to time, t . Based on this method, expressions are deduced forth e eddy current loss and power factor when a thin ferromagnetic plate is subjected to either a sinusoidal surface magnetizing force or sinusoidal flux, under conditions of saturation. The method gives a clear picture of the effects of saturation on the field distribution.

Influence of Power Factor on the Performance of Bulb Tubular Turbine Generator

2020 ◽  
Vol 14 (1) ◽  
pp. 95-102
Author(s):  
Hongbo Qiu ◽  
Hangyu Shen ◽  
Cunxiang Yang ◽  
Ran Yi
Keyword(s):  
Low Power ◽  
Flux Density ◽  
Power Factor ◽  
Eddy Current ◽  
Torque Ripple ◽  
Eddy Current Loss ◽  
Air Gap ◽  
Turbine Generator ◽  
Current Loss ◽  
Transient Electromagnetic

Background: In recent years, many patents have been dedicated to increasing the rated power factor of generators. However, hydro-generators often encounter uncontrollable factors, such as dry season, power network adjustment, and so on, resulting in low power factor operation. In other words, the generator is often in a low power factor operating state. In order to provide data reference for power plant in regulating power factor, it is necessary to analyze the performance of generator in low power factor operation. Objective: The performance of the generator is analyzed when the power factor decreases, and the influence of low power factor operation on the generator is obtained. Methods: Taking a 24MW bulb tubular turbine generator as an example, a 2D transient electromagnetic field model is established. The correctness of the model is verified by comparing the test data and the simulation data. The torque, eddy current loss and air gap flux density of the generator under different power factor are calculated. Results: When the power factor deceases from 0.99 to 0.85, the air gap flux density increases from 0.713 T to 0.749 T, the torque ripple increases from 150.5 kN⋅m to 179.9 kN⋅m, and the rotor eddy current loss increases from 17.48 kW to 18.15 kW. Conclusion: The results show that the torque ripple and eddy current loss will increase with the decrease of power factor when the generator lagging phase operation. The torque ripple and eddy current loss increase by 3.8 % and 1 % respectively with the power factor decrease by 0.02 % with power factor between 0.99 and 0.85.

Performance analysis of magnetic gear with Halbach array for high power and high speed

2020 ◽  
Vol 64 (1-4) ◽  
pp. 959-967
Author(s):  
Se-Yeong Kim ◽  
Tae-Woo Lee ◽  
Yon-Do Chun ◽  
Do-Kwan Hong
Keyword(s):  
Permanent Magnet ◽  
Eddy Current ◽  
High Power ◽  
High Speed ◽  
Torque Ripple ◽  
Eddy Current Loss ◽  
Element Analysis ◽  
Current Loss ◽  
Halbach Array ◽  
Magnetic Gear

In this study, we propose a non-contact 80 kW, 60,000 rpm coaxial magnetic gear (CMG) model for high speed and high power applications. Two models with the same power but different radial and axial sizes were optimized using response surface methodology. Both models employed a Halbach array to increase torque. Also, an edge fillet was applied to the radial magnetized permanent magnet to reduce torque ripple, and an axial gap was applied to the permanent magnet with a radial gap to reduce eddy current loss. The models were analyzed using 2-D and 3-D finite element analysis. The torque, torque ripple and eddy current loss were compared in both models according to the materials used, including Sm2Co17, NdFeBs (N42SH, N48SH). Also, the structural stability of the pole piece structure was investigated by forced vibration analysis. Critical speed results from rotordynamics analysis are also presented.

Development of Interior Permanent Magnet Motors with Concentrated Windings for Reducing Magnet Eddy Current Loss

2009 ◽  
Vol 129 (11) ◽  
pp. 1022-1029 ◽  
Author(s):  
Katsumi Yamazaki ◽  
Yuji Kanou ◽  
Yu Fukushima ◽  
Shunji Ohki ◽  
Akira Nezu ◽  
...  
Keyword(s):  
Permanent Magnet ◽  
Eddy Current ◽  
Eddy Current Loss ◽  
Permanent Magnet Motors ◽  
Current Loss ◽  
Interior Permanent Magnet

scholarly journals An Alternative Method for Calculating the Eddy Current Loss in the Sleeve of a Sealless Pump

Actuators ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 78
Author(s):  
Tomislav Strinić ◽  
Bianca Wex ◽  
Gerald Jungmayr ◽  
Thomas Stallinger ◽  
Jörg Frevert ◽  
...  
Keyword(s):  
Eddy Current ◽  
Three Dimensional ◽  
Eddy Current Loss ◽  
Theoretical Background ◽  
Air Gap ◽  
Magnetic Flux Density ◽  
Pump Impeller ◽  
Current Loss ◽  
Faraday’S Law ◽  
Transient Simulations

A sealless pump, also known as a wet rotor pump or a canned pump, requires a stationary sleeve in the air gap to protect the stator from a medium that flows around the rotor and the pump impeller. Since the sleeve is typically made from a non-magnetic electrically conductive material, the time-varying magnetic flux density in the air gap creates an eddy current loss in the sleeve. Precise assessment of this loss is crucial for the design of the pump. This paper presents a method for calculating the eddy current loss in such sleeves by using only a two-dimensional (2D) finite element method (FEM) solver. The basic idea is to use the similar structure of Ampère’s circuital law and Faraday’s law of induction to solve eddy current problems with a magnetostatic solver. The theoretical background behind the proposed method is explained and applied to the sleeve of a sealless pump. Finally, the results obtained by a 2D FEM approach are verified by three-dimensional FEM transient simulations.

Laminated steel eddy-current loss versus frequency computed using finite elements

2000 ◽  
Vol 36 (4) ◽  
pp. 1132-1137 ◽  
Author(s):  
J.R. Brauer ◽  
Z.J. Cendes ◽  
B.C. Beihoff ◽  
K.P. Phillips
Keyword(s):  
Finite Elements ◽  
Eddy Current ◽  
Eddy Current Loss ◽  
Current Loss

Screening of Eddy Current Loss in Metal Layers of Coated HTS Conductors

2009 ◽  
Vol 19 (3) ◽  
pp. 2851-2854 ◽  
Author(s):  
M. Staines ◽  
K.P. Thakur ◽  
L.S. Lakshmi ◽  
S. Rupp
Keyword(s):  
Eddy Current ◽  
Eddy Current Loss ◽  
Current Loss ◽  
Metal Layers
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