scholarly journals Passive Permanent Magnet Bearing for Rotating Shaft : Analytical Calculation

Author(s):  
Valerie Lemarquand ◽  
Guy Lemarqu
Author(s):  
Jianqi Li ◽  
Yu Zhou ◽  
Jianying Li

This paper presented a novel analytical method for calculating magnetic field in the slotted air gap of spoke-type permanent-magnet machines using conformal mapping. Firstly, flux density without slots and complex relative air-gap permeance of slotted air gap are derived from conformal transformation separately. Secondly, they are combined in order to obtain normalized flux density taking account into the slots effect. The finite element (FE) results confirmed the validity of the analytical method for predicting magnetic field and back electromotive force (BEMF) in the slotted air gap of spoke-type permanent-magnet machines. In comparison with FE result, the analytical solution yields higher peak value of cogging torque.


2021 ◽  
Vol 9 (3) ◽  
pp. 290
Author(s):  
Yukai Li ◽  
Yuli Hu ◽  
Youguang Guo ◽  
Baowei Song ◽  
Zhaoyong Mao

Permanent magnet couplings can convert a dynamic seal into a static seal, thereby greatly improving the stability of the underwater propulsion unit. In order to make full use of the tail space and improve the transmitted torque capability, a conical Halbach permanent magnet coupling (C-HPMC) is proposed in this paper. The C-HPMC combines multiple cylindrical HPMCs with different sizes into an approximately conical structure. Compared with the conical permanent magnet couplings in our previous work, the novel C-HPMC has better torque performance and is easy to process. The analytical calculation method of transmitted torque of C-HPMC is proposed on the basis of torque calculation of the three common types of HPMCs. The accuracy of the torque calculation of the three HPMCs is verified, and the torque performance of the three HPMCSs of different sizes is compared and discussed. The “optimal type selection” method is proposed and applied in the design of C-HPMC. Finally, on the basis of torque analysis calculation and axial force calculation, a complete flowchart of the design and performance analysis of C-HPMC is described.


Author(s):  
Chuan Qu ◽  
Yong-Chen Pei ◽  
Qing-Yuan Xin ◽  
Zhen-Xing Li ◽  
Long Xu

Magnetic-based driving applications are receiving increasing attention. This study proposed a novel reciprocating permanent magnetic actuator (PMA) to manipulate magnetic micro robots to impact and clear blockages inside fluid pipes in a linear path. The PMA consisted of a cylindrical permanent magnet and a crank slider structure. A straight pipe with a circular cross-sectional area was located in front of the actuator to study the driving performance of PMA. A micro permanent magnet with a cylinder shape was employed as a working robot for manipulation inside the pipe. Firstly, analytical formulas were derived to obtain the magnetic driving force acting on the micro robot and determine the most suitable magnet configuration. The finite element simulation verified the analytical calculation. The developed reciprocating PMA prototype was then introduced, and the PMA and micro robot’s motion performance was analysed. Lastly, preliminary experiments were carried out for evaluating the micro robot’s motion characteristics. Performance tests for different excitation frequencies, flow rates, viscosities, and axial distances, indicating that PMA could manipulate the magnetic micro robot inside the pipe. The results confirmed that the developed PMA could effectively drive the micro robot with the advantage of consecutive magnetic driving. Especially, the micro robot featured good flexibility, rapid response, and a simple structure, suggesting that this micro robot may play an important role in industrial and medical applications, such as blockage elimination and thrombus clearance.


1993 ◽  
Vol 29 (6) ◽  
pp. 2932-2934 ◽  
Author(s):  
J.-P. Yonnet ◽  
S. Hemmerlin ◽  
E. Rulliere ◽  
G. Lemarquand

2013 ◽  
Vol 397-400 ◽  
pp. 501-504
Author(s):  
Xin Yi Zhang ◽  
Xing Hua Wang ◽  
Ming Hui Li ◽  
Xue Qin Zhang

High-speed slotless permanent magnet brushless motor based on soft ferrite adopts a large effective air gap structure. For the large effective air-gap, the air-gap flux distribution becomes uneven and the end leakage flux significantly increases. Thus, the traditional analytical method of the phase EMF is inapplicable. This paper deduces the analytical expression of the phase EMF based on the analytical calculation of the air-gap field and analyzes the distribution of the end leakage flux by 3D finite elements methods. Then the end leakage flux is considered by a correction factor of the core length. Finally the analytical calculation method is proved to be feasible by the comparison between the finite elements results and the prototype test results.


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