Journal articles: 'Magnetic bearing'

1

OKADA, Yohji, Hidetoshi MIYAZAWA, Ryou KONDO, and Masato ENOKIZONO. "2A21 Flux Concentrated Hybrid Magnetic Bearing." Proceedings of the Symposium on the Motion and Vibration Control 2010 (2010): _2A21–1_—_2A21–12_. http://dx.doi.org/10.1299/jsmemovic.2010._2a21-1_.

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Hirani, H., and P. Samanta. "Hybrid (hydrodynamic + permanent magnetic) journal bearings." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 221, no. 8 (August 1, 2007): 881–91. http://dx.doi.org/10.1243/13506501jet282.

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Survey of patents on bearings indicates the maturity of hydrodynamic and rapid development of magnetic bearings. Active magnetic bearings are costlier compared with permanent magnetic bearings. To understand the performance characteristics of permanent magnetic bearings, an experimental setup has been developed. Experimental studies on radial permanent magnetic bearings demonstrated the drawbacks, such as high axial thrust and low load capacity. This has led the authors to hybridize the permanent magnet with hydrodynamic technology and to explore the possibility of achieving the low starting torque of a permanent magnetic bearing and the medium to high load carrying capacity of a hydrodynamic bearing in a single bearing arrangement. Simulation is carried out in order to reduce axial force-effect and enhance the radial force supported by the permanent magnetic bearing. Results of simulation on permanent magnetic bearing have been compared with that of published research papers. Finally an algorithm has been developed to investigate the coupling of forces generated by permanent magnets and hydrodynamic actions. Results of load sharing have been reported. The experimentally measured displacements of the shaft running at 500, 2000, and 3000 r/min have been plotted. The effect of hydrodynamics on shaft orbit has been illustrated.

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Kurita, Nobuyuki, Keisuke Ohshio, and Takeo Ishikawa. "4A12 Design of permanent magnet hybrid magnetic bearing with minimum salient poles." Proceedings of the Symposium on the Motion and Vibration Control 2010 (2010): _4A12–1_—_4A12–10_. http://dx.doi.org/10.1299/jsmemovic.2010._4a12-1_.

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Zong, Ming, Xiao Kang Wang, and Yang Cao. "Permanent Magnet Biased Bearing of Suspension System." Advanced Materials Research 383-390 (November 2011): 5529–35. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.5529.

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PM (Permanent Magnet) biased magnetic bearing with PM to replace the magnetic field produced by electromagnet an Active Magnetic Bearing generated static bias magnetic field, it can reduce the power consumption of power amplifier to reduce the number of turns of magnet safety, reduce the volume of magnetic bearings, reducing electromagnetic coil operating current, thereby reducing the power amplifier power control system and heat sink size, magnetic bearings significantly reduce power loss, and fundamentally reduce the cost of bearing. In this paper, a kind of PM biased magnetic bearings, describes its structure and working principle, derived a mathematical model of magnetic bearing and magnetic circuit of PM biased magnetic bearings are calculated, given the specific PM biased magnetic bearing size and accordingly calculate the parameters of magnetic bearings. A magnetic model constructed using Simulink simulation method, and constructed using this method, magnetic bearing specific mathematical model simulation results show that the rotor position in the balance, X and Y decoupling between the control winding, while the deviation from equilibrium position time, X and Y control coupling between the windings, the simulation results and the calculation results.

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Li, Dongjie, Gang Zhang, Zhuoyuan Li, and Jinhua Sun. "Research on Heat Dissipation Scheme of Active Magnetic Bearing Based on ANSYS." Journal of Physics: Conference Series 2383, no. 1 (December 1, 2022): 012114. http://dx.doi.org/10.1088/1742-6596/2383/1/012114.

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Compared to mechanical bearings, active magnetic bearings eliminate mechanical friction, resulting in lower energy losses. However, due to the magnetization characteristics and high-frequency working characteristics of the core material of the active magnetic bearing, there will be high wind friction loss, eddy current loss, hysteresis loss and copper loss in the active magnetic bearing. These losses will generate heat and increase the internal temperature of the bearing, which will not only affect the control accuracy of the active magnetic bearing and the stability of the rotor suspension, but may also cause irreversible damage to the components inside the active magnetic bearing. In this paper, different heat dissipation schemes are established to discuss the influence of the active magnetic suspension bearing on the loss and heat generation of the active magnetic bearing.

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Wang, Li Jun, Xiao Kang Yan, Fei Hu Li, and Zi Xin Dong. "Numerical Simulation of Magnetic Fluid Lubrication." Advanced Materials Research 154-155 (October 2010): 1498–501. http://dx.doi.org/10.4028/www.scientific.net/amr.154-155.1498.

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This paper was concerned with theoretical analysis and the static characteristics of the journal bearing lubricated with magnetic fluid. A general Reynolds equation based on magnetic fluid model is obtained, which can be easily extended to other non-Newtonian fluids and this equation can provide theoretical basis for hydrodynamic analysis of magnetic fluid journal bearings. For the case of static loaded magnetic journal bearings, the influence of magnetic fluid effects on the lubrication performance is studied under various eccentricity ratios, magnetic intensity and concentration. The numerical results show that: with the increasing of concentration, the bearing capacity is obviously increased; the increase magnitude is larger when the eccentricity ratio is large. Under the effect of magnetic field, the bearing capacity increasing with the increasing of magnetic field intensity. When the eccentricity is small, the side leakage is highly decreased. It can be completely eliminate by appropriately designing the bearing geometry and the magnetic field which can’t be existed in normal journal bearings.

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Maslen, E. H., P. E. Allaire, M. D. Noh, and C. K. Sortore. "Magnetic Bearing Design for Reduced Power Consumption." Journal of Tribology 118, no. 4 (October 1, 1996): 839–46. http://dx.doi.org/10.1115/1.2831617.

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Magnetic bearings have relatively low power consumption compared to fluid film and rolling element bearings. They are now candidates for supporting gas turbines and aeropropulsion engines. This paper describes the design and construction of permanent magnet biased, actively controlled magnetic bearings for a flexible rotor. The rotor was originally supported in fluid film bearings consuming as much as 3000 watts of power. For the magnetic bearing, both permanent magnets and electromagnets are used in a configuration which effectively provides the necessary fluxes in the appropriate air gaps to support the rotor. The theoretical development related to the bearing design is presented along with some experimental performance results. The results include measurements of power consumption, load capacity, bearing linearized coefficients, and the dynamic response of the rotor. The measured total power consumption, excluding shaft losses, was 210 watts in the permanent magnet biased bearing.

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Ling, Xiao, He Xiwu, and Cheng Wenjie. "Analysis of eddy current field for new type of thrust bearings based on single-objective genetic algorithm." International Journal of Applied Electromagnetics and Mechanics 64, no. 1-4 (December 10, 2020): 263–70. http://dx.doi.org/10.3233/jae-209330.

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Based on the working condition of the magnetic thrust bearing (MTB), the single-objective optimization model (SOOM) is built. The optimum design of structure parameters for two types of magnetic bearings including traditional carbon bearing and soft magnetic composite (SMCs) bearing has been carried out using genetic algorithm. The analysis of eddy current field for two types of bearings are obtained by FEM. It is found that the maximum eddy current field of SMCs bearing is less than that of carbon steel one, and the air gap magnetic density is larger than that of carbon steel bearing at the same frequency. SMCs obtained by the compression of insulated soft magnetic powders have low eddy current. Thus, under the same magnetic force conditions, the input current of SMCs bearings is lower than that of carbon steel ones. The analysis shows that SMCs can replace carbon steel and has superiority in bearing application.

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9

Allaire, P. E., E. H. Maslen, D. W. Lewis, and R. D. Flack. "Magnetic Thrust Bearing Operation and Industrial Pump Application." Journal of Engineering for Gas Turbines and Power 119, no. 1 (January 1, 1997): 168–73. http://dx.doi.org/10.1115/1.2815543.

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Magnetic bearings represent a new bearing technology, which has some advantages over conventional fluid film and wiling element bearings for some applications. The paper describes the basic concepts of magnetic thrust bearing operation involving the magnetic actuator, electronic controls, power amplifier, and sensor. The magnetic actuator is a magnetic circuit, which generates attractive forces. These support the rotating shaft. While it is often thought that magnetic bearings are highly nonlinear devices, this paper demonstrates that they are linear in both the perturbation flux and current when used in a double acting configuration. Electronic feedback controls are used to stabilize the bearing. Example design parameters are presented for an application to an industrial canned motor pump.

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10

Bassani, R., and S. Villani. "Passive magnetic bearings: The conic-shaped bearing." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 213, no. 2 (February 1999): 151–61. http://dx.doi.org/10.1243/1350650991542901.

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Heshmat, H., H. Ming Chen, and J. F. Walton,. "On the Performance of Hybrid Foil-Magnetic Bearings." Journal of Engineering for Gas Turbines and Power 122, no. 1 (October 20, 1999): 73–81. http://dx.doi.org/10.1115/1.483178.

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Recent technological advancements make hybridization of the magnetic and foil bearings both possible and extremely attractive. Operation of the foil/magnetic bearing takes advantage of the strengths of each individual bearing while minimizing each other’s weaknesses. In this paper one possible hybrid foil and magnetic bearing arrangement is investigated and sample design and operating parameters are presented. One of the weaknesses of the foil bearings, like any hydrodynamic bearing, is that contact between the foil bearing and the shaft occurs at rest or at very low speeds and it has low load carrying capacity at low speeds. For high speed applications, AMBs are, however, vulnerable to rotor-bending or structural resonances that can easily saturate power amplifiers and make the control system unstable. Since the foil bearing is advantageous for high speed operation with a higher load carrying capacity, and the magnetic bearing is so in low speed range, it is a natural evolution to combine them into a hybrid bearing system thus utilizing the advantages of both. To take full advantage of the foil and magnetic elements comprising a hybrid bearing, it is imperative that the static and dynamic characteristics of each bearing be understood. This paper describes the development of a new analysis technique that was used to evaluate the performance of a class of gas-lubricated journal bearings. Unlike conventional approaches, the solution of the governing hydrodynamic equations dealing with compressible fluid is coupled with the structural resiliency of the bearing surfaces. The distribution of the fluid film thickness and pressures, as well as the shear stresses in a finite-width journal bearing, are computed. Using the Finite Element (FE) method, the membrane effect of an elastic top foil was evaluated and included in the overall analytical procedure. Influence coefficients were generated to address the elasticity effects of combined top foil and elastic foundation on the hydrodynamics of journal bearings, and were used to expedite the numerical solution. The overall program logic proved to be an efficient technique to deal with the complex structural compliance of various foil bearings. Parametric analysis was conducted to establish tabulated data for use in a hybrid foil/magnetic bearing design analysis. A load sharing control algorithm between the foil and magnetic elements is also discussed. [S0742-4795(00)01201-1]

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Kim, Dokyu, SeungJoon Baik, and JeongIk Lee. "Instability Study of Magnetic Journal Bearing under S-CO2 Condition." Applied Sciences 11, no. 8 (April 13, 2021): 3491. http://dx.doi.org/10.3390/app11083491.

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A supercritical CO2 (S-CO2)-cooled Brayton cycle is under development for distributed power applications for remote regions. In order to successfully develop it, issues of controlling shaft levitation with bearings have to be solved. From several studies, magnetic bearings have been suggested for reliable levitation performance with reduced cost and complexity. However, several studies on magnetic bearing show that instability issues under high-pressure fluid and high-speed operating conditions may exist. The purpose of this research is to provide background for understanding the instability of magnetic bearings under S-CO2 conditions and propose functional requirements of the magnetic bearing. Thus, the rotating shaft with magnetic bearings operating under high pressure fluid was first analyzed. To test the theory, a magnetic bearing test rig was constructed. By comparing experimental data to the analysis results, the analysis results were verified. Therefore, the analysis results can be used for predicting instability in the future and can contribute to the development of better magnetic bearing controllers.

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13

Dhar, D., and L. E. Barrett. "Design of Magnetic Bearings for Rotor Systems With Harmonic Excitations." Journal of Vibration and Acoustics 115, no. 3 (July 1, 1993): 359–66. http://dx.doi.org/10.1115/1.2930357.

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This paper presents a method for calculating the control forces and the bearing stiffness and damping coefficients to control the response of multi-mass flexible rotor systems mounted on magnetic bearings and subjected to unbalance or harmonic excitation forces. The capability for inclusion of hydrodynamic bearings is retained to model seal effects or to permit the design of magnetic bearings for hybrid systems. Control forces at the magnetic bearing locations are evaluated based on the desired shaft response specified by the modal coordinates. These forces are determined such that the error between the desired response and the achieved response is minimized in a least-square sense. Equivalent bearing coefficients are calculated from the control forces and the achieved response which when superimposed on the nominal bearing coefficients yield the resultant magnetic bearing coefficients required for control. An example case is presented where control of rotor response has been attempted at the first and the second unbalance critical speeds. The results demonstrate appreciable improvement in response using magnetic bearings.

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14

Xiao, Ling, Tianyang Hou, Ming Li, and Wenjie Cheng. "Dynamic performances of a magnetic thrust bearing based on new soft magnetic composites." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 10 (November 25, 2018): 3388–99. http://dx.doi.org/10.1177/0954406218813587.

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According to the material theory and analysis method, the characteristics of the soft magnetic composites were analyzed. As the required magnetic properties can be achieved by adjusting the formulation ratio, the high electrical resistivity (about 10−4 Ωm) and decent magnetic properties were obtained. Based on the good performance, soft magnetic composites were firstly applied to the magnetic thrust bearings. The dynamic models including the dynamic stiffnesses, magnetic force based on the effective reluctance model were analyzed. The parameters for soft magnetic composites were obtained by experiments and theoretical calculations. The results showed that the dynamic bandwidth of magnetic force for the bearing with MgO-based soft magnetic composites can reach more than 1000 Hz, which is far beyond that for carbon steel bearing. If the magnetic permeability is further increased to 650, the dynamic bandwidth of the electromagnetic force can also exceed 1000 Hz for the magnetic thrust bearings made by soft magnetic composites. Therefore, the possibility of magnetic thrust bearing made by soft magnetic composites instead of carbon steel materials is equipped with the satisfactory performance, which may provide a theoretical basis and technical support for high-performance magnetic thrust bearing.

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15

Owusu-Ansah, Prince, Yefa Hu, and Rhoda Afriyie Mensah. "Active Magnetic Bearing as a Force Measurement System." International Journal of Materials, Mechanics and Manufacturing 5, no. 3 (August 2017): 209–12. http://dx.doi.org/10.18178/ijmmm.2017.5.3.320.

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16

LIU Qiang, 刘. 强., 赵. 勇. ZHAO Yong, 代峰燕 DAI Feng-yan, 任. 元. REN Yuan, and 王卫杰 WANG Wei-jie. "Novel internal Lorentz magnetic bearing for magnetic bearing gyrowheel." Optics and Precision Engineering 26, no. 2 (2018): 399–409. http://dx.doi.org/10.3788/ope.20182602.0399.

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GAHLER, Conrad, Manuel MOHLER, and Raoul HERZOG. "Magnetic Bearing. Multivariable Identification of Active Magnetic Bearing Systems." JSME International Journal Series C 40, no. 4 (1997): 584–92. http://dx.doi.org/10.1299/jsmec.40.584.

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18

Vorwaller, M. Ryan, Kuo Chi Lin, Ji Hua Gou, Chan Ham, and Young Hoon Joo. "Testbed for a Wind Turbine with Magnetic Bearing." Advanced Materials Research 512-515 (May 2012): 657–60. http://dx.doi.org/10.4028/www.scientific.net/amr.512-515.657.

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World-wide demands for sustainable energy have brought increased attention to the improvement of wind turbine technology. Magnetic bearings promise to improve wind turbine performance by reducing frictional losses and mitigating vibration due to rotor imbalance and wind disturbances. However, testing must be performed to validate and quantify these advantages if magnetic bearings are to be used efficiently. Therefore, a practical testbed for a wind turbine with a magnetic bearing system has been developed, including the design of a passive rare earth magnetic bearing and fixture. This testbed will provide experimental vibration and efficiency data needed to extend past research in wind turbine modeling and design to include recent advances in magnetic bearing technology.

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Allaire, P. E., R. L. Fittro, E. H. Maslen, and W. C. Wakefield. "Measured Force/Current Relations in Solid Magnetic Thrust Bearings." Journal of Engineering for Gas Turbines and Power 119, no. 1 (January 1, 1997): 137–42. http://dx.doi.org/10.1115/1.2815537.

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When magnetic bearings are employed in a pump, compressor, turbine, or other rotating machine, measurement of the current in the bearing coils provides knowledge of the forces imposed on the bearings. This can be a significant indicator of machine problems. Additionally, magnetic bearings can be utilized as a load cell for measuring impeller forces in test rigs. The forces supported by magnetic bearings are directly related to the currents, air gaps, and other parameters in the bearings. This paper discusses the current/force relation for magnetic thrust bearings. Force versus current measurements were made on a particular magnetic bearing in a test rig as the bearing coil currents were cycled at various time rates of change. The quasi-static force versus current relations were measured for a variety of air gaps and currents. The thrust bearing exhibits a hysteresis effect, which creates a significant difference between the measured force when the current is increasing as compared to that when the current is decreasing. For design current loops, 0.95 A to 2.55 A, at the time rate of change of 0.1 A/s, the difference between increasing and decreasing current curves due to hysteresis ranged from 4 to 8 percent. If the bearing is operated in small trajectories about a fixed (nonzero) operation point on the F/I (force/current) curve, the scatter in the measurement error could be expected to be on the order of 4 percent. A quasi-static nonlinear current/force equation was developed to model the data and curve-fit parameters established for the measured data. The effects of coercive force and iron reluctance, obtained from conventional magnetic materials tests, were included to improve the model, but theoretically calculated values from simple magnetic circuit theory do not produce accurate results. Magnetic fringing, leakage, and other effects must be included. A sinusoidal perturbation current was also imposed on the thrust bearing. Force/current magnitude and phase angle values versus frequency were obtained for the bearing. The magnitude was relatively constant up to 2 Hz but then decreased with frequency. The phase lag was determined to increase with frequency with value of 16 deg at 40 Hz. This effect is due to eddy currents, which are induced in the solid thrust-bearing components.

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Wang, Xiaoguang, Qian Liu, Yefa Hu, Xin Cheng, Haohui Chen, and Longfei Huang. "The Redundant Design and Reliability Analysis of Magnetic Bearings Used for Aeroengine." Advances in Mechanical Engineering 6 (January 1, 2014): 157461. http://dx.doi.org/10.1155/2014/157461.

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The redundant design principle of weak coupling magnetic bearing system for aeroengine is put forward. A redundant design scheme of weak coupling magnetic bearing system is provided including radial and axial magnetic bearings and their control system. The performance of the weak coupling redundant magnetic bearing is analyzed with the finite element method and then compared with the strong coupling redundant magnetic bearing. The weak coupling redundant magnetic bearing has some advantages in both redundancy and load bearing capacity under the circumstance of either no failure or partial failure in the coils. In view of the increase in the number of electronic components in the control system, both reliability and redundancy are evaluated comprehensively. A compromise solution of 12-pole structure for the weak coupling redundant magnetic bearing is recommended.

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Li, Qiang, Yefa Hu, and Huachun Wu. "Structure Design and Optimization of the Radial Magnetic Bearing." Actuators 12, no. 1 (January 6, 2023): 27. http://dx.doi.org/10.3390/act12010027.

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According to different working environments and functional requirements, radial magnetic bearings (RMBs) have various design methods. Some methods’ lack of effectiveness or accuracy is likely to cause significant differences in the structural performance of magnetic bearings, which will cause serious problems such as limited bearing capacity and complex control. This paper analyzes the structure topology of a magnetic bearing according to the application scenario of RMBs, then proposes a general design example of an 8-pole magnetic bearing based on magnetic circuit analysis and reveals the linearity between electromagnetic force and current as well as air gap through finite element analysis and the influence of magnetic saturation on the load capacity of the magnetic bearing structure. After completing the preliminary design, we further optimize the structure, take the genetic algorithm as an example to iterate the influence coefficient, and summarize and prospect. The design scheme and optimization method proposed in this paper only provide a valuable reference for researchers and factories when devising RMB devices.

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22

Jung, Hoon Hyung, Seung Hee Kang, Bang Hyun Cho, and Chae Sil Kim. "A Design Technique for a Magnetic Bearing-Rotor in a Turbo Blower Considering Critical Speeds." Advanced Materials Research 569 (September 2012): 564–67. http://dx.doi.org/10.4028/www.scientific.net/amr.569.564.

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This paper introduces a rotor design technique for a turbo blower supported by magnetic bearings that considers the critical speeds of the rotor. An important factor for rotor critical speeds is the stiffness of its bearings. The magnetic bearing acts as a negative spring, called the position stiffness prior to operation, and rotor systems are initially unstable until the stiffness (current stiffness) and damping in the active control rotating system are determined using closed loop control forces. This paper describes a finite element model for the rotor, derives the stiffness equations for the magnetic bearing, and defines the total magnetic bearing stiffness including the position stiffness and current stiffness. Finally, the magnetic bearing stiffness that avoids the rotor critical speeds is chosen.

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23

Ma, Zhihao, Gai Liu, Yichen Liu, Zhaocheng Yang, and Huangqiu Zhu. "Research of a Six-Pole Active Magnetic Bearing System Based on a Fuzzy Active Controller." Electronics 11, no. 11 (May 29, 2022): 1723. http://dx.doi.org/10.3390/electronics11111723.

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Magnetic bearings have a series of excellent qualities, such as no friction and abrasions, high speed, high accuracy, and so on, which have fundamentally innovated traditional forms of support. In order to solve the problems of the large volume, low power density and high coupling coefficient of three-pole magnetic bearings, a six-pole AC active magnetic bearing is designed. Firstly, the basic structure and working principle of a two-degree-of-freedom (2-DOF) six-pole active magnetic bearing is introduced. Secondly, a suspension force modeling method of a 2-DOF AC active magnetic bearing based on the Maxwell tensor method is proposed, and the mathematical model of active magnetic bearing is established. Considering the fact that AC active magnetic bearing is essentially a nonlinear system, a fuzzy active disturbance rejection control (ADRC) method is designed based on fuzzy control and ADRC theory. Its control algorithm and control block diagram are given, and the fuzzy ADRC method is simulated and verified. Finally, the control block diagram of an experimental system based on the 2-DOF six-pole active magnetic bearing is given, and the experimental platform is constructed. The experimental results show that the mechanical and magnetic circuit structure of the 2-DOF six-pole active magnetic bearing is reasonable, and the fuzzy controllers can realize the stable suspension of the rotor.

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Zhu, Yu, Yu Liu, and Ming Zhang. "Analysis of a New Magnetic Bearing for Magnetic Levitation Stages." Advanced Materials Research 295-297 (July 2011): 2106–11. http://dx.doi.org/10.4028/www.scientific.net/amr.295-297.2106.

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This paper proposed a new configuration of magnetic bearings used in magnetic levitation stages. The equivalent current sheet model is introduced to calculate the levitation force of the proposed magnetic bearing, and the experiment result validates the correctness of the calculation method. The relationships of structural parameters to the levitation force and axial stiffness are studied, which prove that the new magnetic bearing has larger levitation force with lower axial stiffness over the working stroke and could be applied in ultra-precision magnetic levitation stages.

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Hamler, A., V. Goric̆an, B. Štumberger, M. Jesenik, and M. Trlep. "Passive magnetic bearing." Journal of Magnetism and Magnetic Materials 272-276 (May 2004): 2379–80. http://dx.doi.org/10.1016/j.jmmm.2003.12.972.

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Fan, Man, Xi Ping Wang, Wei Li, Li Guo, and Yu Min Yang. "Analysis on Axial Magnetic Force of Permanent Axial Bearing by Axial Magnetized." Applied Mechanics and Materials 150 (January 2012): 12–16. http://dx.doi.org/10.4028/www.scientific.net/amm.150.12.

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Permanent magnet axial bearing axial stiffness analysis is critical in the design process of permanent magnetic bearing. This article establishes the axial magnetic model through the equivalent magnetic charge method, but the equivalent magnetic charge method solving the axial force need work out four complicated quadruple integrals. The calculation cycle the traditional method is too long, and even cannot get analytical solution. On the contrary, the method of through Forcal language programming to approximate computation bearing axial force makes the solving process simplification. The stiffness of the permanent magnet bearing with equivalent magnetic charge method is verified by comparing the simulating result obtained by using the finite element method. The conclusion is that the equivalent magnetic charge method can be used to calculate the axial stiffness of permanent magnet bearings and provide the basis of the axial permanent bearings design.

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Cao, Shinan, Pingjuan Niu, Wei Wang, Tiantian Zhao, Qiang Liu, Jie Bai, and Sha Sheng. "Novel Magnetic Suspension Platform with Three Types of Magnetic Bearings for Mass Transfer." Energies 15, no. 15 (August 5, 2022): 5691. http://dx.doi.org/10.3390/en15155691.

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For ultra-precision, large stroke, and high start/stop acceleration, a novel magnetic suspension platform with three types of magnetic bearings is proposed. The structure and working principle of the novel platform are introduced. The passive magnetic bearings are used to compensate for the weight of the actuator. The repulsive force of the passive magnetic bearing model is established and analyzed. The Lorentz force-type magnetic bearings are used to provide driving force and rotational torque in the XY-plane. The driving force model and rotational torque model are established. The electromagnetic suspension bearing is used to provide driving force in the Z-axis and rotational torque along the X-axis and Y-axis. A novel Halbach magnetic array is designed to improve the magnetic flux density in the air gap. The finite element method is used to validate the force model, torque model, and magnetic flux density in the air gap. The results show that the maximum force of the passive magnetic bearing is 79 N, and the rotational torque stiffness is 35 N/A in the XY-plane and 78 N/A along the Z-axis. The driving force stiffness is 91 N/A in the XY-plane and 45 N/A along Z-axis.

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MATSUMURA, Fumio, Yohji OKADA, Masayuki FUJITA, and Toru NAMERIKAWA. "Magnetic Bearings. State of the Art of Magnetic Bearings. (Overview of Magnetic Bearing Research and Applications)." JSME International Journal Series C 40, no. 4 (1997): 553–60. http://dx.doi.org/10.1299/jsmec.40.553.

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Zhang, Fa Jun, Wen Jie Fang, Chang Zhou, and Zhong Liu. "A Fuzzy Control Simulation about Bearing Residual Magnetic Treatment." Applied Mechanics and Materials 80-81 (July 2011): 899–903. http://dx.doi.org/10.4028/www.scientific.net/amm.80-81.899.

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This paper is based on using fuzzy control method and according to the size of bearing residual magnetic detective distance and the diameter of bearing ring; it accurately controls the size of demagnetization machine alternating current. The result shows that the fuzzy control method on bearing residual magnetic quality control by simulation can get a rational control effect of the size of demagnetization machine current. It provides a new theoretical method for precisely controlling the residual magnetic bearings quality.

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Bornstein, K. R. "Dynamic Load Capabilities of Active Electromagnetic Bearings." Journal of Tribology 113, no. 3 (July 1, 1991): 598–603. http://dx.doi.org/10.1115/1.2920665.

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Magnetic bearings are finding increasing use in a wide range of applications. It is well known that the static capacity of a bearing can be determined by its saturation point. The static capacity has often been the prime criterion for the selection of magnetic bearing size. The dynamic capacity of a bearing is a much more complicated function. This paper will develop equations to express the dynamic load capacity of a magnetic bearing in terms of its amplifier size, the frequency of excitation, the magnetic airgap, the method of force actuation, and certain nondimensional terms.

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Xiao, Y., K. Y. Zhu, C. Zhang, K. J. Tseng, and K. V. Ling. "Stabilizing Synchronization Control of Rotor-Magnetic Bearing Systems." Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 219, no. 7 (November 1, 2005): 499–510. http://dx.doi.org/10.1243/095965105x33572.

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Active magnetic bearings, which provide non-contact suspension for high-speed rotors, have received increasing attention in recent years. Although the contactless nature of magnetic bearings brings up many advantages over conventional bearings, one of the challenging problems is to stabilize the rotor of the magnetic bearing systems that is very sensitive to outside disturbances and plant uncertainties. In this paper, a stabilizing synchronization design of rotor-magnetic bearing systems is proposed by incorporating cross-coupling technology into the optimal control architecture, which can be decomposed into two problems: a robust optimal control problem to improve the synchronization performance of the rotor in the radial directions and a stability problem. The control scheme is based on minimization of a new quadratic performance index in which the synchronization errors are embedded. Stability of the control scheme is also investigated through the linear quadratic Gaussian (LQG) optimal control technique. Simulations on a compact and efficient flywheel energy storage system with integrated magnetic bearings demonstrate that the proposed approach is very effective to recover the unstable system when the outside disturbances are present.

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Kurnyta-Mazurek, Paulina, Artur Kurnyta, and Maciej Henzel. "Measurement System of a Magnetic Suspension System for a Jet Engine Rotor." Sensors 20, no. 3 (February 6, 2020): 862. http://dx.doi.org/10.3390/s20030862.

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This paper presents laboratory results on the measurement system of a magnetic suspension bearing system for a jet engine rotor of an unmanned aerial vehicle (UAV). Magnetic suspension technology enables continuous diagnostics of a rotary machine and eliminates of the negative properties of classical bearings. This rotor-bearing system consists of two radial magnetic bearings and one axial (thrust) magnetic bearing. The concept of the bearing system with a magnetically suspended rotor for UAV is presented in this paper. Rotor geometric and inertial characteristics were assumed according to the parameters of a TS-21 jet engine. Preliminary studies of the measurement system of rotor engines were made on a laboratory stand with homopolar active magnetic bearings. The measurement system consisted of strain gauges, accelerometers, and contactless proximity sensors. During the research, strains were registered with the use of a wireless data acquisition (DAQ) system. Measurements were performed for different operational parameters of rotational rotor speed, control system parameters, and with the presence of disturbance signals from the control system. In this paper, obtained operational characteristics are presented and discussed.

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Chen, Jun Hui, Feng Yu Yang, Chao Rui Nie, Jun Yang, and Peng Yan Wan. "Magnetic Force Characteristics and Structure of a Novel Radial Hybrid Magnetic Bearing." Applied Mechanics and Materials 150 (January 2012): 69–74. http://dx.doi.org/10.4028/www.scientific.net/amm.150.69.

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There are some problems in the permanent magnetic circuit of the current permanent magnet biased magnetic bearings, such as small magnetic force, low magnetic flux density and lack of self-stabilization. To solve this problem, a new hybrid radial magnetic bearing structure has been proposed. The nonlinear model and linearization equation of the new hybrid radial magnetic bearing capacity has been established by current molecular method and virtual displacement theorem. It is found that the permanent magnetic bearing can achieve self-stabilization in the radial degrees of freedom and can reduce the total displacement of negative stiffness. The results show that the air gap flux density is greatly improved by the new hybrid magnetic bearing with Halbach array structure. Current stiffness and displacement rigidity is closely related to initial current and initial gap of the equilibrium position. Near the equilibrium position, current stiffness and displacement rigidity are linear relationship. With the increase of air gap, it remains a good linearity. While with the decrease of air gap, it presents nonlinear characteristics..

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Xie, Zhen Yu, Hong Kai Zhou, and Xiao Wang. "Effects of the Magnetic Damper Locations on Dynamic Characteristics of the Active Magnetic Bearing System in Manufacturing Engineering." Applied Mechanics and Materials 252 (December 2012): 51–55. http://dx.doi.org/10.4028/www.scientific.net/amm.252.51.

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The magnetic damper was introduced into the high speed rotating machinery to restrain the vibration of the rotor supported by active magnetic bearings. The experimental setup, which was made up of one rotor, two radial active magnetic bearings, one axial active magnetic bearing, one magnetic damper and control system, was built to investigate the effects of the magnetic damper locations on dynamic characteristics of the system by theoretical analysis, experimental modal analysis and actual operation of the system. The results show that the vibration of the active magnetic bearing system operating at the modal frequency can be reduced more effectively if the magnetic damper is located far from the nodes of the corresponding mode shape.

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Xiao, Lin Jing, and Hong Chang Ding. "Study on Stiffness and Damping Characteristic of Hybrid Magnetic Bearing for High-Speed Electrical Machine." Advanced Materials Research 338 (September 2011): 534–38. http://dx.doi.org/10.4028/www.scientific.net/amr.338.534.

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This paper focuses on the stiffness and damping characteristic of hybrid magnetic bearing for high-speed electrical machine. Firstly, it analyzes the structure and working principle of hybrid magnetic bearing, according to the bearing’s magnetic circuit properties, it deduces the equation of the bearing’s magnetic force with displacement and current. Then, combining with the controller parameters it deduces the stiffness and damping equation of magnetic bearing. At last it simulates the stiffness and damping characteristic curve, and the obtained simulation results can give theoretical support for rotor dynamic analysis and modal analysis.

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Cheng, Baixin, Xin Cheng, Shao Song, Huachun Wu, Yefa Hu, Rougang Zhou, and Shuai Deng. "Active Disturbance Rejection Control in Magnetic Bearing Rotor Systems with Redundant Structures." Sensors 22, no. 8 (April 14, 2022): 3012. http://dx.doi.org/10.3390/s22083012.

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At present, magnetic bearings are a better energy-saving choice than mechanical bearings in industrial applications. However, there are strongly coupled characteristics in magnetic bearing–rotor systems with redundant structures, and uncertain disturbances in the electrical system as well as external disturbances, and these unfavorable factors degrade the performance of the system. To improve the anti-interference performance of magnetic bearing systems, this paper proposes the inverse of the current distribution matrix W−1 meaning that the active disturbance rejection control simulation model can be carried out without neglecting the current of each coil. Firstly, based on the working mechanism of magnetic bearings with redundant structures and the nonlinear electromagnetic force model, the current and displacement stiffness models of magnetic bearings are established, and a dynamic model of the rotor is constructed. Then, according to the dynamic model of the rotor and the mapping relationship between the current of each coil and the electromagnetic force of the magnetic bearing, we established the equivalent control loop of the magnetic bearing–rotor system with redundant structures. Finally, on the basis of the active disturbance rejection control (ADRC) strategy, we designed a linear active disturbance rejection controller (LADRC) for magnetic bearings with redundant structures under the condition of no coil failure, and a corresponding simulation was carried out. The results demonstrate that compared to PID+current distribution control strategy, the LADRC+current distribution control strategy proposed in this paper is able to effectively improve the anti-interference performance of the rotors supported by magnetic bearings with redundant structures.

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Spakovszky, Z. S., J. D. Paduano, R. Larsonneur, A. Traxler, and M. M. Bright. "Tip Clearance Actuation With Magnetic Bearings for High-Speed Compressor Stall Control." Journal of Turbomachinery 123, no. 3 (February 1, 2000): 464–72. http://dx.doi.org/10.1115/1.1370163.

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Magnetic bearings are widely used as active suspension devices in rotating machinery, mainly for active vibration control purposes. The concept of active tip-clearance control suggests a new application of magnetic bearings as servo-actuators to stabilize rotating stall in axial compressors. This paper presents a first-of-a-kind feasibility study of an active stall control experiment with a magnetic bearing servo-actuator in the NASA Glenn high-speed single-stage compressor test facility. Together with CFD and experimental data a two-dimensional, incompressible compressor stability model was used in a stochastic estimation and control analysis to determine the required magnetic bearing performance for compressor stall control. The resulting requirements introduced new challenges to the magnetic bearing actuator design. A magnetic bearing servo-actuator was designed that fulfilled the performance specifications. Control laws were then developed to stabilize the compressor shaft. In a second control loop, a constant gain controller was implemented to stabilize rotating stall. A detailed closed loop simulation at 100 percent corrected design speed resulted in a 2.3 percent reduction of stalling mass flow, which is comparable to results obtained in the same compressor by Weigl et al. (1998. ASME J. Turbomach. 120, 625–636) using unsteady air injection. The design and simulation results presented here establish the viability of magnetic bearings for stall control in aero-engine high-speed compressors. Furthermore, the paper outlines a general design procedure to develop magnetic bearing servo-actuators for high-speed turbomachinery.

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Fan, Yi Hua, Ying Tsun Lee, Chung Chun Wang, and Yi Lin Liao. "Passive Magnetic Bearing Design for a Small Wind Generator System." Applied Mechanics and Materials 145 (December 2011): 174–78. http://dx.doi.org/10.4028/www.scientific.net/amm.145.174.

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A passive magnetic thrust bearing for a small vertical wind generator system is considered in this paper. The passive magnetic bearing is designed to reduce the axial load of the rotor system. The load capacity of the passive magnetic bearing is analyzed by finite element analysis software. From the simulation results, a suitable solution for the passive magnets of the test wind generator system is verified to be 225.6N with about a 2mm air gap. The experiment results show that a wind generator system with the additional passive magnetic bearing can start at a lower wind speed and transfers more power to the generator. The proposed hybrid bearing system can increase efficiency by 20%~50%, as compared with a traditional system supported by roller bearings at the same wind speed.

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Zhong, P., and M. A. Townsend. "Stability of Magnetic Bearing-Rotor Systems Having a Central Support Backup Bearing." Journal of Dynamic Systems, Measurement, and Control 117, no. 3 (September 1, 1995): 277–82. http://dx.doi.org/10.1115/1.2799117.

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The unperturbed (fully nonlinear) stability of a magnetic bearing-rotor system having a single central backup bearing near the middle of the shaft is analyzed under conditions of magnetic bearing(s) failure for zero gravity using the Lyapunov second (direct) method; these results are shown to apply with gravity, based on observed similiaries of the nonlinear Lagrangian equations. These are completely general stability criteria for practical values of system parameters and conditions of system operation and failure. It turns out that the center-backup bearing configuration has some considerable advantages over conventional designs: in addition to known results for stability and instability, the system can be stable when one or both magnetic bearings fail (has negative stiffness). This “temporary stability” depends upon inherent gyroscopic forces and may be lost when dissipative forces are introduced. The results are applicable to other gyroscopic systems.

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Liao, Ping, Su Yang Ma, Guo Qing Wu, Jing Feng Mao, and An Dong Jiang. "The Analysis of Radial Magnetic Bearing’s Magnetic Field in Active Magnetic Bearing Electric Spindle Unit." Advanced Materials Research 291-294 (July 2011): 1593–99. http://dx.doi.org/10.4028/www.scientific.net/amr.291-294.1593.

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Introduced the working principle of active magnetic bearing unit and took the electric spindle with 5.5kW for example, finite element analysis of the magnetic fields of radical magnetic bearing was analyzed through finite element analysis by ANSYS software to find out the variation of magnetic field distribution and affecting factors. Analysis results showed that radical magnetic bearing had small leakage magnetic field, the principal axis’ maximum offset from the ideal center line was 0.0025mm and the principal axis had superior radical running accuracy when the circularity of supporting journal on principal axis was 0.003mm, the unilateral air-gap value was 0.3mm while the principal axis suspended normally and the inside track’ circularity of magnetic pole was 0.007mm. It can meet the working requirements of precision machine tool. The research results provided theoretical basis for structural optimization of the active magnetic bearing unit.

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Sathiya Moorthy, R., and A. Mohamed Siddhique. "Finite Element Analysis of Active Magnetic Bearing with Different Leg Shapes." Applied Mechanics and Materials 813-814 (November 2015): 899–904. http://dx.doi.org/10.4028/www.scientific.net/amm.813-814.899.

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High speed machining technology is an important trend of advanced manufacturing engineering because of its accuracy. Spindle used in high speed machinery are capable of operating at high speed. As the spindle rotates at high speed, heat is generated in the contact area between the bearings and spindle. This heat generation leads thermal deformation and results in inaccuracy during machining. To avoid the heat generation non-contact bearing like active magnetic bearing (AMB) has been used. The main limitation in active magnetic bearing is its large size. In view of this, an attempt has been made to design and analysis of active magnetic bearing to reduce size complexity. In this paper we have mainly focused on the leg geometry effect and size of the active magnetic bearing. ANSYS workbench tool is used to analyse the flux density in pole area and calculate the maximum load carrying capacity of the bearing.

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Srinivasan, S., E. H. Maslen, and L. E. Barrett. "Optimization of Bearing Locations for Rotor Systems With Magnetic Bearings." Journal of Engineering for Gas Turbines and Power 119, no. 2 (April 1, 1997): 464–68. http://dx.doi.org/10.1115/1.2815597.

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This paper presents a method for quickly evaluating the effect of changes in bearing location on bearing design for stability of rotating machinery. This method is intended for use by rotating machinery designers to select the “best” bearing locations prior to the bearing design process. The purpose of the method is to improve the design process by separating the problem of determining the “best” bearing locations from that of determining the actual bearing design. The method is independent of the type of bearing employed. For each candidate bearing configuration, the method provides a scalar measure of the relative ability of bearings to meet stability specifications. Within certain limits, the stability specifications are defined by the designer. The scalar measure is used to rank the candidate bearing locations and thereby select the best one. The scalar measure is compared to a practical measure of magnetic bearing design such as the infinity norm of the controller for an example design of a multistage centrifugal compressor.

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Maslen, E. H., C. K. Sortore, G. T. Gillies, R. D. Williams, S. J. Fedigan, and R. J. Aimone. "Fault Tolerant Magnetic Bearings." Journal of Engineering for Gas Turbines and Power 121, no. 3 (July 1, 1999): 504–8. http://dx.doi.org/10.1115/1.2818501.

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A fault tolerant magnetic bearing system was developed and demonstrated on a large flexible-rotor test rig. The bearing system comprises a high speed, fault tolerant digital controller, three high capacity radial magnetic bearings, one thrust bearing, conventional variable reluctance position sensors, and an array of commercial switching amplifiers. Controller fault tolerance is achieved through a very high speed voting mechanism which implements triple modular redundancy with a powered spare CPU, thereby permitting failure of up to three CPU modules without system failure. Amplifier/cabling/coil fault tolerance is achieved by using a separate power amplifier for each bearing coil and permitting amplifier reconfiguration by the controller upon detection of faults. This allows hot replacement of failed amplifiers without any system degradation and without providing any excess amplifier kVA capacity over the nominal system requirement. Implemented on a large (2440 mm in length) flexible rotor, the system shows excellent rejection of faults including the failure of three CPUs as well as failure of two adjacent amplifiers (or cabling) controlling an entire stator quadrant.

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Thomas, C. A., and K. P. Reimer. "Vibrations of turbo-molecular vacuum pumps with high stable magnetic bearings operating within electronic microscope systems." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 368–69. http://dx.doi.org/10.1017/s0424820100086143.

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In order to operate Electronic Microscopes vibration free, it is necessary to assemble the apparatus on a vibration free isolated desk. Similarly, strict requirements, regarding vibrations, are demanded from the attached vacuum pump which provides vacuum for the system. The rotor and rotating shaft of Turbo Molecular Pumps with mechanical bearings are connected to the pump housing by means of ball bearings. The inertia and vibration component resulting from the ball bearing dynamic effects produce the vibration results as indicated in Fig. 1.In order to design a Turbo Molecular Pump with minimum vibration effects it was necessary to provide the pump with a magnetic bearing system containing 4 passive and 1 active controlled axis. This magnetic bearing system is less sensitive to vibration and simpler in assembly than other existing more complicated 5-axis active controlled versions. However it is more complication than the mechanical bearing type. The magnet bearing is provided with a touch-down bearing. Larger pump movements due to high or low frequency stimulation recieved via the microscope desk could result in forcing the shaft out of its magnet-bearing-centre position, the touch-down bearing now re-centres the shaft allowing immediate magnetic bearing centre recovery.

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Kun-Xi Qian, Pei Zeng, W. Ru, and Hai-Yu Yuan. "Novel magnetic spring and magnetic bearing." IEEE Transactions on Magnetics 39, no. 1 (January 2003): 559–61. http://dx.doi.org/10.1109/tmag.2002.806524.

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Liu, Ming Xue, Ye Fa Hu, Ru Hao Dong, Shi Min Peng, and Hua Chun Wu. "Load Analysis and Structure Design of Small-Scale Maglev Wind Turbine." Applied Mechanics and Materials 624 (August 2014): 308–14. http://dx.doi.org/10.4028/www.scientific.net/amm.624.308.

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To effectively reduce friction torque and start-up wind speed, magnetic bearing was applied to the small-scale wind turbine. Load analysis is the primary task of the design for magnetic bearing in wind turbine. Based on a typical blade model, the aerodynamic performance of the impeller was simulated using Computational Fluid Dynamics (CFD) method. The characteristics and differences of the impeller’s aerodynamic performance under different wind speeds were analyzed and the aerodynamic loads were calculated as well. Moreover, the bearing capacity of magnetic bearing was calculated according to the forces on the spindle. A kind of permanent magnetic bearing (PMB) was designed for the radial supporting of the spindle in wind turbine. A prototype of the small-scale maglev wind turbine (SMWT) was presented, which provides some basis for the application of magnetic bearings in wind turbines.

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Ho, Y. S., H. Liu, and L. Yu. "Effect of Thrust Magnetic Bearing on Stability and Bifurcation of a Flexible Rotor Active Magnetic Bearing System." Journal of Vibration and Acoustics 125, no. 3 (June 18, 2003): 307–16. http://dx.doi.org/10.1115/1.1570448.

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This paper is concerned with the effect of a thrust active magnetic bearing (TAMB) on the stability and bifurcation of an active magnetic bearing rotor system (AMBRS). The shaft is flexible and modeled by using the finite element method that can take the effects of inertia and shear into consideration. The model is reduced by a component mode synthesis method, which can conveniently account for nonlinear magnetic forces and moments of the bearing. Then the system equations are obtained by combining the equations of the reduced mechanical system and the equations of the decentralized PID controllers. This study focuses on the influence of nonlinearities on the stability and bifurcation of T periodic motion of the AMBRS subjected to the influences of both journal and thrust active magnetic bearings and mass eccentricity simultaneously. In the stability analysis, only periodic motion is investigated. The periodic motions and their stability margins are obtained by using shooting method and path-following technique. The local stability and bifurcation behaviors of periodic motions are obtained by using Floquet theory. The results indicate that the TAMB and mass eccentricity have great influence on nonlinear stability and bifurcation of the T periodic motion of system, cause the spillover of system nonlinear dynamics and degradation of stability and bifurcation of T periodic motion. Therefore, sufficient attention should be paid to these factors in the analysis and design of a flexible rotor system equipped with both journal and thrust magnetic bearings in order to ensure system reliability.

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Vavilov, V. E. "Mathematical model of the hybrid system of magnetic levitation energy production equipment autonomous power 97 supply systems." Transportation systems and technology 2, no. 3 (September 15, 2016): 97–108. http://dx.doi.org/10.17816/transsyst20162397-108.

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Introduction. Typically, when developing mathematical models magnetocavitation systems (magnetic bearings, electrostatic bearings, hybrid magnetic bearings (GMP, etc.) is considered just the very bearing as a separate, isolated Electromechanical system. This approach allows us to accurately explore the process magnetocavitation systems, but practically does not allow to evaluate the processes occurring in the system of magnetic bearing-object position. To solve this problem, the author proposes a different approach to the analysis of the processes in magnetocavitation systems in General and GPC in particular considering the magnetic bearing-object position, as a single complex. Goal. The work aimed the creation of a generalized analytical model of high-speed, AMPE with coercivity permanent magnet (VPM) on an elastic bearing supports, taking into account the mutual influence of processes in AMPA and bearing supports. This task is new and relevant and is essential to modern engineering. To solve this problem this paper developed a generalized mathematical model of the rotor system on a hybrid magnetic suspension. Evaluate the impact of hybrid magnetic bearings on the overall behavior of the rotor system. Performed analysis of processes in Electromechanical energy converters and mechanical processes occurring in the rotary system. Method and methodology. The research methodology is based on the joint solution of Maxwell equations and equations describing the mechanical processes of a rotor system with five degrees of freedom. Conclusion. The generalized mathematical model of high-speed, AMPE with VPM on a non-contact bearing supports and conducted her research. Based on research of the developed mathematical model, the authors developed an original control algorithm for the rotor position in a hybrid magnetic bearings, which allows for the design of high-speed, AMPE with VPM to abandon the position sensors of the rotor. In addition, on the basis of the results of calculations, a method was developed for diagnostics of eccentricity of rotor are high-speed, AMPE with VPM, as well as new methods of calculation of high-speed, AMPE with VPM, past experimental verification.

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Kumar, Vivek, and Satish C. Sharma. "Magneto-hydrostatic lubrication of thrust bearings considering different configurations of recess." Industrial Lubrication and Tribology 71, no. 7 (September 9, 2019): 915–23. http://dx.doi.org/10.1108/ilt-10-2018-0370.

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Purpose This paper aims to numerically investigate the influence of magnetic field and recess configurations on performance of hydrostatic thrust bearing. Electrically conducting fluid is supplied to bearing, operating in external magnetic field. Influences of recess geometric shapes (circular, rectangular, elliptical and triangular) and restrictor (capillary and orifice) are numerically examined on stead-state and dynamic performance characteristics of bearing. Design/methodology/approach Numerical simulation of hydrostatic thrust bearing has been performed using finite element (FE) method based on Galerkin’s technique. An iterative source code based on FE approach, Gauss–Siedel and Newton–Raphson method is used to compute steady-state and dynamic performance indices of bearings. Findings The presence of magnetic field is observed to be enhancing load-carrying capacity and damping coefficient of bearings. The effect is observed to be more pronounced at low value of Hartmann number, because of the saturation effect observed at higher values of Hartmann number. The enhancement in abovementioned performance indices is observed to be highly dependent on geometry of recess and restrictor. Research limitations/implications This study presents a FE-based approach to numerically simulate a hydrostatic thrust bearing. It will help bearing designers and academician in selecting an appropriate recess shape, restrictor and strength of magnetic field, for obtaining optimum performance from hydrostatic thrust bearing. Originality/value The present investigation provides a coupled solution of modified Reynolds equation and restrictor equation, which is essential for accurately predicting the performance of hydrostatic thrust bearings.

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Lee, Chong-Won, Young-Ho Ha, Chee-Young Joh, and Cheol-Soon Kim. "In-Situ Identification of Active Magnetic Bearing System Using Directional Frequency Response Functions." Journal of Dynamic Systems, Measurement, and Control 118, no. 3 (September 1, 1996): 586–92. http://dx.doi.org/10.1115/1.2801184.

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Complex modal testing is employed to obtain the directional frequency responses of a four-axis active magnetic bearing system. In the test, magnetic bearings are used as exciters while the system is in operation. The directional frequency response estimates are then used to effectively identify the parameters of the active magnetic bearing system. Experimental results show that the directional frequency response function, which is properly defined in the complex domain, is a powerful tool for identification of bearing as well as modal parameters of the system.

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Journal articles on the topic 'Magnetic bearing'

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