scholarly journals STATIC ECCENTRICITY FAULT DETECTION METHOD FOR ELECTRICAL ROTATING MACHINES BASED ON THE MAGNETIC FIELD ANALYSIS IN THE AIR GAP BY MEASURING COILS

2020 ◽  
Vol 69 (4) ◽  
pp. 3-7
Author(s):  
Stjepan Tvorić ◽  
Miroslav Petrinić ◽  
Ante Elez ◽  
Mario Brčić
Keyword(s):  
Magnetic Field ◽  
Fault Detection ◽  
Air Gap ◽  
Field Analysis ◽  
Detection Methods ◽  
Electrical Machine ◽  
Rotating Machines ◽  
Static Eccentricity ◽  
Machine Fault ◽  
The Magnetic Field

Electrical rotating machines have a great economic significance as they enable conversion of energy between mechanical and electrical state. Reliability and operation safety of these machines can be greatly improved by implementation of continuous condition monitoring and supervisory systems. Especially important feature of such systems is the ability of early fault detection. For this reason, several methods for detection and diagnosis of the machine faults have been developed and designed. As fault detection methods can largely differ in the types of detectable faults, machine adoptability and price of the system, a novel method was developed that can be used for cost-effective detection of various faults of electrical machine. Machine fault detection technique presented in this paper is based on the measurement of magnetic field in the air gap. Numerous studies have proven that crucial information about the machine condition can be determined based on measurement and analysis of the magnetic field in the air gap. It has also been confirmed that analysis of the air gap magnetic field can be used to detect, diagnose and recognize various electrical faults in their very early stage. Proposed method of positioning and installation of the measuring coils on ferromagnetic core parts within the air gap region of the machine enables differentiation of various faults. Furthermore, different faults can be detected if measuring coils are placed on the stator teeth then when placed on the rotor side. The paper presents method on how to analyse and process the measured voltages acquired from measuring coils placed within the machine, especially in the case of rotor static eccentricity detection. The methodology is explained by means of finite element method (FEM) calculations and verified by measurements that were performed on the induction machine. FEM calculation model was used to predict measurement coil output of the induction motor for healthy and various faulty states (at different amounts of static eccentricity). These results were then confirmed by measurements performed in the laboratory on the induction traction motor that was specially modified to enable measurements of faulty operation states of the machine. Measurements comprised of several machine fault conditions broken one rotor bar, broken multiple rotor bars, broken rotor end ring and various levels of rotor static eccentricity. Other methods used for faults detection are primarily based on the monitoring of quantities such as current and vibration and their harmonic analysis. This new system is based on the tracing the changes of induced voltage of the measuring coils installed on the stator teeth. Faults can be detected and differentiated based on RMS value of these voltages and the number of voltage spikes of voltage waveform i.e. without the need of harmonic analyses. If these coils are installed on the rotor it is possible to detect the stator winding faults in a similar manner.

Electromagnetic Field Analysis and Measurement for High Speed Attraction Type Magnetic Levitation Vehicle Systems

2005 ◽  
Vol 295-296 ◽  
pp. 655-660
Author(s):  
D.X. Chen ◽  
M.C. Pan ◽  
F.L. Luo ◽  
Z.W. Kang ◽  
W.G. Tian ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Speed ◽  
Magnetic Levitation ◽  
Experimental System ◽  
Air Gap ◽  
Field Analysis ◽  
The Finite Element Method ◽  
Magnetic Field Analysis ◽  
Vehicle Systems ◽  
The Magnetic Field

Research achievements in a high speed attraction type magnetic levitation vehicle experimental system are reported. The high speed attraction type magnetic levitation vehicle constitutes a typical long stator linear synchronous motor. The study on levitation and propulsive electromagnetic fields is of great importance and is studied. Owing to the influence of the stator grooves and the material discontinuousness, the magnetic field distribution is very complex to be analyzed in analytical forms. The magnetic fields in the air gap are determined using the finite element method. The levitation force and thrust produced by the levitation magnetic field and the propulsive magnetic field are calculated. They are found to vary following the change of the air gap and exciting current. A magnetic field strength measurement system based on a hall sensor is designed. Experimental results are compared with the results from the magnetic field analysis.

scholarly journals Design of a New 1D Halbach Magnet Array with Good Sinusoidal Magnetic Field by Analyzing the Curved Surface

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2522
Author(s):  
Guangdou Liu ◽  
Shiqin Hou ◽  
Xingping Xu ◽  
Wensheng Xiao
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Permanent Magnets ◽  
Air Gap ◽  
Curved Surface ◽  
Magnetic Flux Density ◽  
Sinusoidal Magnetic Field ◽  
The Magnetic Field

In the linear and planar motors, the 1D Halbach magnet array is extensively used. The sinusoidal property of the magnetic field deteriorates by analyzing the magnetic field at a small air gap. Therefore, a new 1D Halbach magnet array is proposed, in which the permanent magnet with a curved surface is applied. Based on the superposition of principle and Fourier series, the magnetic flux density distribution is derived. The optimized curved surface is obtained and fitted by a polynomial. The sinusoidal magnetic field is verified by comparing it with the magnetic flux density of the finite element model. Through the analysis of different dimensions of the permanent magnet array, the optimization result has good applicability. The force ripple can be significantly reduced by the new magnet array. The effect on the mass and air gap is investigated compared with a conventional magnet array with rectangular permanent magnets. In conclusion, the new magnet array design has the scalability to be extended to various sizes of motor and is especially suitable for small air gap applications.

2-D Magnetic Field Analysis of Air Cylinder with MR Sensor

2011 ◽  
Vol 121-126 ◽  
pp. 2706-2709
Author(s):  
Dan Jiang ◽  
Ping Yang ◽  
Kun Jiang
Keyword(s):  
Magnetic Field ◽  
Field Analysis ◽  
Magnetic Flux Density ◽  
Piston Motion ◽  
Element Analysis ◽  
Pneumatic Control ◽  
Magnetoresistive Sensor ◽  
Magnetic Field Analysis ◽  
Working Principle ◽  
The Magnetic Field

As a type of solid state switch, MR (magnetoresistive) sensor detects the air cylinder piston’s position in pneumatic control system. The construction and working principle of the air cylinder with MR sensor are introduced. Using 2-D magnetic field finite element analysis (FEA) method, the magnetic field distribution of air cylinder with piston motion is analyzed. Simulation results are given. The magnetic flux density characteristics are compared between piston wear or not.

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.

The 3D Magnetic Field Analysis of Excitation Unit of Drill Pipe MFL Testing Based on ANSYS

2013 ◽  
Vol 694-697 ◽  
pp. 1179-1182
Author(s):  
Yi Lai Ma ◽  
Li Lin ◽  
Kai Wen Jiang ◽  
Xu Lin Zhao
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Drill Pipe ◽  
Magnetic Flux Leakage ◽  
Field Analysis ◽  
Ansys Software ◽  
Magnetic Field Analysis ◽  
The Cost ◽  
The Magnetic Field ◽  
Flux Leakage

Magnetic flux leakage is one type of electromagnetic nondestructive testing (NDT) which is widely utilized in the testing the integrity of drill pipe in the field. In this paper, the 3D model of excitation unit is completely built and analyzed by ANSYS software. The magnetic field of drill pipe in the combination of full excitation device is showed by ANSYS software instead of the physic experiments which increases the efficiency tremendously and decreases the cost and achieves the anticipated desire. It is considered that this technique can provide the theoretical basis of drill pipe excitation device and the magnetic flux leakage testing of drill pipe.

Magnetic Field Analysis of Surface-Mounted Permanent-Magnet Motors

2011 ◽  
Vol 52-54 ◽  
pp. 285-290
Author(s):  
Yi Chang Wu ◽  
Feng Ming Ou ◽  
Bo Wei Lin
Keyword(s):  
Magnetic Field ◽  
Permanent Magnet ◽  
Magnetic Circuit ◽  
Circuit Model ◽  
Field Analysis ◽  
Permanent Magnet Motors ◽  
Element Analysis ◽  
Magnetic Field Analysis ◽  
Field Estimation ◽  
The Magnetic Field

The prediction of the magnetic field is a prerequisite to investigate the motor performance. This paper focuses on the magnetic field estimation of surface-mounted permanent-magnet (SMPM) motors based on two approximations, i.e., the magnetic circuit analysis and the finite-element analysis (FEA). An equivalent magnetic circuit model is applied to analytically evaluate the magnetic field of a SMPM motor with exterior-rotor configuration. The two-dimensional FEA is then applied to numerically calculate the magnetic field and to verify the validity of the magnetic circuit model. The results show that the errors between the analytical predictions and FEA results are less than 6%. It is of benefit to further design purposes and optimization of SMPM motors.

Design of the Superconducting Excitation Winding for 12 MW Direct-Drive Wind Generator

2014 ◽  
Vol 672-674 ◽  
pp. 217-221
Author(s):  
Lu Shun Su ◽  
Qing He ◽  
Jing Shi ◽  
Li Ren ◽  
Jie He ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Power Generation ◽  
Air Gap ◽  
Offshore Wind ◽  
Direct Drive ◽  
Offshore Wind Turbines ◽  
Superconducting Coils ◽  
The Stability ◽  
The Magnetic Field ◽  
Excitation Winding

Due to the high JC of the superconductor, the volume and the weight of the generator can be significantly reduced if the superconducting coils are used. This paper has designed a 40-pole racetrack excitation winding for the 12MW offshore wind turbines generator. The excitation winding are wound by Nb-Ti superconductor, running at the temperature of 4.2K. In order to ensure the stability and reliability of the magnetic field, some optimizers for the design of the excitation winding are adopted. As a result, the fundamental magnetic field at the air-gap center of the armature winding could reach 2.1T, thereby the 12MW power generation could be achieved.

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