scholarly journals Electron beam halo formation in high-power periodic permanent magnet focusing klystron amplifiers

2000 ◽  
Vol 28 (3) ◽  
pp. 502-510 ◽  
Author(s):  
Chiping Chen ◽  
R. Pakter
2020 ◽  
Vol 64 (1-4) ◽  
pp. 959-967
Author(s):  
Se-Yeong Kim ◽  
Tae-Woo Lee ◽  
Yon-Do Chun ◽  
Do-Kwan Hong

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.


2021 ◽  
Vol 11 (11) ◽  
pp. 4856
Author(s):  
Hae-Sol Lee ◽  
Myeong-Hwan Hwang ◽  
Hyun-Rok Cha

As unmanned aerial vehicles expand their utilization and coverage, research is in progress to develop low-weight and high-performance motors to efficiently carry out various missions. An electromagnetic field interior permanent magnet (IPM) motor was designed and analyzed in this study that improved the flight performance and flight duration of an unmanned aerial vehicle (UAV). The output power and efficiency of a conventional commercial UAV motor were improved by designing an IPM motor of the same size, providing high power output and high-speed operation by securing high power density, wide speed range, and mechanical stiffness. The cooling performance and efficiency of the drive motor were improved without requiring a separate power source for cooling by introducing the helical-grooved self-cooling case, which has a low heat generation structure. Furthermore, the motor is oil-cooled through rotating power without a separate power source, reducing the weight of the UAV. The heat dissipation characteristics were verified by fabricating a prototype and taking actual measurements to verify the validity of the heat dissipation characteristics. The results of this study are expected to improve the flight duration and performance of UAVs and contribute to the efficiency of the design of a UAV drive motor.


2000 ◽  
Author(s):  
Vladimir I. Perevodchikov ◽  
V. N. Shapenko ◽  
V. F. Martynov ◽  
P. M. Stalkov ◽  
A. L. Shapiro

2014 ◽  
Vol 21 (1) ◽  
pp. 013104 ◽  
Author(s):  
O. Dumbrajs ◽  
K. A. Avramidis ◽  
J. Franck ◽  
J. Jelonnek

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