Field Distribution of Strongly Excited Magnetic Lenses

1975 ◽  
Vol 33 ◽  
pp. 140-141
Author(s):  
M. Strojnik
Keyword(s):  
Flux Density ◽  
Field Distribution ◽  
Optical Axis ◽  
Operating Point ◽  
Pole Piece ◽  
Partial Saturation ◽  
Axial Flux ◽  
The Stability

Magnetic lenses operating in partial saturation offer two advantages in HVEM: they exhibit small cs and cc and their power depends little on the excitation IN. Curve H, Fig. 1, shows that the maximal axial flux density Bz max of one of the lenses investigated changes between points (3) and (4) by 5% as the excitation varies by 40%. Consequently, the designer can relax the requirements concerning the stability of the lens current supplies. Saturated lenses, however, can only be used if (i) unwanted fields along the optical axis can be controlled, (ii) 'wobbling' of the optical axis due to inhomogeneous saturation around the pole piece faces is prevented, (iii) ample ampere-turns can be squeezed into the space available, and (iv) the lens operating point covers a sufficient range of accelerating voltages.

scholarly journals Vision-Based Target Detection and Tracking for a Miniature Pan-Tilt Inertially Stabilized Platform

Electronics ◽  
2021 ◽  
Vol 10 (18) ◽  
pp. 2243
Author(s):  
Jianchuan Guo ◽  
Chenhu Yuan ◽  
Xu Zhang ◽  
Fan Chen
Keyword(s):  
Target Detection ◽  
Feedback Linearization ◽  
Visual Servoing ◽  
Control Method ◽  
Sliding Mode ◽  
Optical Axis ◽  
Detection And Tracking ◽  
The Stability ◽  
Stabilized Platform ◽  
The Mathematical Model

This paper presents a novel visual servoing sheme for a miniature pan-tilt intertially stabilized platform (ISP). A fully customized ISP can be mounted on a miniature quadcopter to achieve stationary or moving target detection and tracking. The airborne pan-tilt ISP can effectively isolate a disturbing rotational motion of the carrier, ensuring the stabilization of the optical axis of the camera in order to obtain a clear video image. Meanwhile, the ISP guarantees that the target is always on the optical axis of the camera, so as to achieve the target detection and tracking. The vision-based tracking control design adopts a cascaded control structure based on the mathematical model, which can accurately reflect the dynamic characteristics of the ISP. The inner loop of the proposed controller employs a proportional lag compensator to improve the stability of the optical axis, and the outer loop adopts the feedback linearization-based sliding mode control method to achieve the target tracking. Numerical simulations and laboratory experiments demonstrate that the proposed controller can achieve satisfactory tracking performance.

Stability of Multi-Stage Axial Flow Compressors

1964 ◽  
Vol 15 (4) ◽  
pp. 328-356 ◽  
Author(s):  
W. T. Howell
Keyword(s):  
Axial Flow ◽  
Rotational Frequency ◽  
Oscillatory Instability ◽  
Operating Point ◽  
Axial Flow Compressor ◽  
Multi Stage ◽  
Wide Range ◽  
Surge Line ◽  
Flow Compressor ◽  
The Stability

SummaryThe following theoretical investigation is concerned with the stability of the flow through a system composed of a multi-stage axial flow compressor followed by a throttle.Such an investigation was carried out by Pearson and Bowmer in 1949. In 1962 Pearson’s work on the analysis of axial flow compressor characteristics, and the accumulation of empirical data regarding factors affecting the surge line, re-awakened interest in the possibility of predicting the surge line of a multi-stage axial flow compressor-throttle system.In this paper the equations governing the stability of flow at any operating point in such a system are obtained by applying Kirchhoff’s laws to the associated electric circuit at that operating point, and the analysis is applied to a wide range of flows of the calculated characteristics of a seven-stage axial flow compressor.A study of the simplest compressor-throttle system is given, in which the equations of motion of the system are derived mechanically and electrically, and the range of validity of the equations and their stability are discussed in order to bring out the relation between the mathematics and physics of the simple system before applying these methods to multi-stage axial flow compressors.For the relatively simple electrical representation used in this paper for an axial compressor of n stages, there are shown to be 2n possible values of p, the transient rotational frequency, and these are determined over a sufficiently wide range of flows on the seven-stage compressor studied.As a result, a region of the compressor characteristic map can be marked out in which all the values of the transient rotational frequency have their real parts less than zero, corresponding to stability of operation, a region where at least one of the values of p is real and positive corresponding to non-oscillatory instability of operation, and an intermediate region where some of the values of the rotational frequency p are complex with positive real part, corresponding to oscillatory instability of operation.It is suggested that the non-oscillatory instability found here is associated with the surge and the line of inception of non-oscillatory instability with the surge line.

Optimization of magnetic hat for quartz flexible accelerometer

Sensor Review ◽  
2016 ◽  
Vol 36 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Cuo Wang ◽  
Xingfei Li ◽  
Ke Kou ◽  
Chunguo Long
Keyword(s):  
Magnetic Field ◽  
Field Distribution ◽  
Cylindrical Symmetry ◽  
Air Gap ◽  
Magnetic Sensors ◽  
Magnetic Field Distribution ◽  
Navigation Systems ◽  
Pole Piece ◽  
Content Type ◽  
The Magnetic Field

Purpose – This study aims to ameliorate the strength and uniformity of the magnetic field in the air-gap of quartz flexible accelerometers. Quartz flexible accelerometers (QFAs), a type of magneto-electric inertial sensors, have wide applications in inertial navigation systems, and their precision, linearity and stability performance are largely determined by the magnetic field in operation air-gap. To enhance the strength and uniformity of the magnetic field in the air-gap, a magnetic hat structure has been proposed to replace the traditional magnetic pole piece which tends to produce stratiform magnetic field distribution. Design/methodology/approach – Three-dimensional analysis in ANSYS workbench helps to exhibit magnetic field distribution for the structures with a pole piece and a magnetic hat, and under the hypothesis of cylindrical symmetry, two-dimensional finite element optimization by ANSYS APDL gives an optimal set of dimensions of the magnetic hat. Findings – Three structures of the QFA with a pole piece, a non-optimized magnetic hat and an optimized magnetic hat are compared by the simulation in ANSYS Maxwell and experiments measuring the electromagnetic rebalance force. The results show that the optimized hat can supply stronger and more uniform magnetic field, which is reflected by larger and more linear rebalance force. Originality/value – To the authors ' knowledge, the magnetic hat and its dimension optimization have rarely been reported, and they can find significant applications in designing QFAs or other similar magnetic sensors.

A comparison of injection laws for the space charge equations in gases and dielectrics

1993 ◽  
Vol 443 (1919) ◽  
pp. 517-546 ◽  
Keyword(s):  
Electric Field ◽  
Space Charge ◽  
Field Distribution ◽  
Steady Motion ◽  
Plane Geometry ◽  
Symmetric Problem ◽  
Injection Process ◽  
Underlying Geometry ◽  
Current Characteristics ◽  
The Stability

We consider the steady motion of space charge from an injecting electrode to an earthed electrode in both a gas and a dielectric. Three models governing the process of charge injection from the electrode into the medium are compared and the resulting voltage–current characteristics calculated. In particular we examine injection laws in which the electric field, charge or current are specified. It is shown that if the injecting electrode is small in comparison to the underlying geometry then the resulting field distribution is almost independent of the injection process. The stability of the three models is compared and it is shown that the field specified and charge specified models are always stable. The calculations are performed exactly for the case of a symmetric problem and make use of the Deutsch approximation for a needle-plane geometry.

scholarly journals Pengaruh Geometri dan Kuat Medan Permanen dari Magnet Permanen NdFeB Terhadap Output Generator Fluks Aksial

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
SILVIANA SIMBOLON
Keyword(s):  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Rotation Speed ◽  
Visual Basic ◽  
Magnetic Flux Density ◽  
Axial Flux ◽  
Ndfeb Permanent Magnet ◽  
Maximum Voltage ◽  
Permanent Magnet Generator

Abstrak: Pada penelitian ini, telah dilakukan investigasi pengaruh bentuk geometri dan magnetik flux density terhadap outputtegangan dari generator axial flux magnet permanen. Model dari generator axial didesain menggunakan sofware 3D StudioMax dan visual basic net express. Pada simulasi dan eksperimen digunakan magnet permanen NdFeB yang dibentuk circulardan rectangular dengan variasi magnetik flux density 0,5; 0,8; 1,1; 1,3 Tesla pada kecepatan rotasi sekitar 260 – 540 rpm. Darihasil simulasi dan eksperimen ditunjukkan bahwa geometri magnet permanen sangat mempengaruhi dalam menghasilkanmagnetik flux density maksimum. Hasil ini juga menunjukkan adanya korelasi antara output tegangan maksimum denganmagnetik fluk density maksimum. Semakin besar magnetik fluk density dan kecepatan rotor putar (rotasi) akan menghasilkanoutput tegangan yang semakin besar.Kata kunci: generator, magnetic flux density, rotasi, voltageAbstract: In this paper, the influence of geometric shapes and magnetic flux density on the maximum Voltage (Emax) of theaxial flux permanent magnet generator has been investigated. Modeling of axial flux permanent magnet generator wasdesigned using 3D Studio Max and visual basic net express software. The simulation and experimentally were performed byusing NdFeB permanent magnet in the form of rectangular and circular shape with various Magnetic Flux Densities as 0.5,0.8, 1.1, and 1.3 Tesla at the rotation speed around 260-540 rpm. The obtained results both from simulation and experimentshow that the magnetic geometry, in this case the cross-section A, is directly proportional to the maximum magnetic flux,(Фmax). The results also showed that there was a correlation between the maximum Voltage (Emax) and the maximum magneticflux, ((Фmax). The increasing of magnetic flux density and rotor rotation increases the output voltage.Keywords: generator, magnetic flux density, rotation, voltage

Sign in / Sign up

Export Citation Format

Share Document