scholarly journals The Development of Fluxgate Magnetometer for Non–Destructive Measurement

2012 ◽  
Author(s):  
Soon Leong Chew ◽  
Rashdi Shah Ahmad ◽  
Rosly Jaafar
Keyword(s):  
Magnetic Flux ◽  
Low Cost ◽  
Current Source ◽  
Low Frequency ◽  
Ferromagnetic Material ◽  
Magnetic Sensor ◽  
Fluxgate Magnetometer ◽  
Ferrite Ring ◽  
Non Destructive ◽  
Ring Core

Pengukuran tanpa musnah bahan feromagnet dan gangguan medan magnet frekuensi rendah memerlukan penderia medan magnet yang mempunyai kepekaan yang tinggi dan stabil. Magnetometer yang berasaskan prinsip fluxgate dan memenuhi ciri-ciri yang diperlukan telah dibina dengan menggunakan teras gelang ferit. Teras gelang ferit ini dipacukan dengan sumber arus untuk mencapai keadan histerisis. Gelung pengesan yang dililit merentasi gelang ferit akan mengesan perubahan medan magnet yang berlaku pada gelang ferit tersebut. Teknik pengesanan yang digunakan adalah berasaskan pengesanan harmonik kedua oleh suatu pengesan fasa. Penderia fluxgate yang dibina adalah murah mudah dibina, mampu mengesan arah medan magnet dan tahan lasak. Kata kunci: Fluxgate; penderia medan magnet; histerisis; feromagnet Non–Destructive measurements of ferromagnetic material and low frequency magnetic flux distrubance require a highly sensitive and stable magnetic sensor with directional capabilities. A magnetometer based on fluxgate principle that meets the requirement had been developed using a ferrite ring core. The ferrite ring core is excited by an excitation current source to achieve hysteresis condition. The pick up coil that is wound across the ring core will pick up the magnetic flux generated in the ring core. This sensing method is based on the conventional type of fluxgate magnetometer with detection of second harmonics by a phase sensitive detector. Major advantages of the fluxgate magnetometer are low cost, directional, easy to construct, reliable and rugged. Key words: Fluxgate; magnetic sensor; hysteresis; ferromagnetic

scholarly journals Amplitude Control Method of Magnetic Flux Vertical Modulation Structure for TMR Magnetic Sensor Based on Harmonic Component of Modulated Signal

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 722
Author(s):  
Junsheng Zhang ◽  
Mengchun Pan ◽  
Qingfa Du ◽  
Jiafei Hu ◽  
Kun Sun ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Control Method ◽  
Amplitude Ratio ◽  
Second Harmonic ◽  
Harmonic Component ◽  
Low Frequency ◽  
Magnetic Sensor ◽  
Modulation Method ◽  
Temperature Drift ◽  
Amplitude Control

Magnetic flux vertical modulation method based on piezoelectric resonance can reduce the 1/f noise of tunnel magnetoresistance (TMR) magnetic sensor and significantly improves the low-frequency magnetic field detectivity. However, the amplitude variation of the modulation structure will lead to the instability of the sensor output. In order to improve the amplitude stability of the modulation structure, an amplitude control method based on the amplitude ratio of the first and second harmonic components of the modulated signal was proposed. Compared with the piezoelectric or capacitive feedback method, this method does not require an independent amplitude conversion circuit, and has the advantages of simple structure, high control efficiency and strong anti-interference ability. The experimental results showed that the amplitude and temperature drift of the modulated structure was significantly suppressed, which is of great significance for enhancing the adaptability of the TMR magnetic sensor to the application environments.

scholarly journals Design and Implementation of Three axis Fluxgate Magnetometer and its Applications

2020 ◽  
Vol 9 (4) ◽  
pp. 960-965
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Flux ◽  
7 Tesla ◽  
Scientific Instrument ◽  
Fluxgate Magnetometer ◽  
Design And Implementation ◽  
Field Lines ◽  
The Magnetic Field ◽  
Ring Core

A scientific instrument which measures the magnetic field strength and its direction is known as Magnetometer. In this article a three axis Fluxgate Magnetometer is constructed by using simple ring core and simple drive circuits instead of specialized components like Hall Effect sensors. This type of Fluxgate magnetometers is working on the principle of magnetic flux linking a coil depends on the orientation of the coil with respect to the earth’s magnetic field lines. Here the three single axis fluxgate magnetometers are designed and placed perpendicular to each other on a board. The circuit is designed to produce 100 KHz frequency and to measure the Magnetic field in the range up to 7 Tesla. The sensitivity is tested through an external electromagnet. The readings are obtained in LAB-VIEW platform and the three-axis data is displayed.

Dielectric Properties in Fresh Trabecular Bone Tissue from 1MHz to 1000MHz: A Fast and Non Destructive Quality Evaluation Technique

2010 ◽  
Vol 638-642 ◽  
pp. 730-735 ◽  
Author(s):  
Ramiro M. Irastorza ◽  
Sergio Valente ◽  
Fernando Vericat ◽  
Eugenia Blangino
Keyword(s):  
Dielectric Properties ◽  
Frequency Domain ◽  
Quality Evaluation ◽  
Low Cost ◽  
Low Frequency ◽  
Electrical Impedance Spectroscopy ◽  
Sample Population ◽  
Strongly Correlated ◽  
Trabecular Bones ◽  
Non Destructive

The increasing research on development of novel bio-materials has resulted in several studies on non-destructive evaluation methods for characterizing these materials and the biological materials receiving them. A broad range of techniques are available. As an alternative tool, electrical impedance spectroscopy, has become a widely used, non destructive and low cost technique in material quality evaluation. Particularly in bones, it has also been demonstrated that mechanical characteristics are strongly correlated to dielectric properties. In this work, non destructive estimation (the same samples can be tested using other techniques) of the dielectric properties of fresh trabecular bones (layered lossy structure) using coaxial probes is analyzed from 1MHz to 10MHz (in frequency domain) and from 80MHz to 1GHz (in both, frequency and time domain). Frequency domain system identification is used to build the estimation in the low frequency range and an orthonormal based identification approach, for the high frequency data. Comments on conductive samples, non Debye dielectrics and polarization effects are added. The methodology was applied to a particular human sample population of aged adult femur heads and results are presented here. A comparison with destructive test, in which the samples were machined into cylinders of 7mm diameter, is also performed.

Study on Low Frequency AC Excitation Magnetic Flux Leakage Testing for Defects With Different Depths

2018 ◽  
Author(s):  
Xinyuan Lu ◽  
Guanghai Li ◽  
Liangchao Chen ◽  
Yu Chang ◽  
Xiaozhu Zhang
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Low Frequency ◽  
Ferromagnetic Material ◽  
Magnetic Flux Leakage ◽  
Detection Depth ◽  
Ac Current ◽  
Different Depths ◽  
Ac Excitation ◽  
Flux Leakage

Magnetic flux leakage (MFL) method is a non-destructive method commonly used for equipment with ferromagnetic material. This paper presents a low frequency alternating current (AC) excitation MFL method. This method uses low frequency AC current excitation to obtain a high detection depth, and to realize the examination of internal and external surface of the ferromagnetic structures. Based on the low frequency AC excitation simulation model built in ANSYS Electronics18.1 software, the amplitude and phase parameters of magnetic field were extracted and calculated. With the changes of the defect depths in different positions of the steel plate, the results of amplitude and phase parameters of magnetic field were studied and analyzed. Then the experiments of detection on artificial defects with different depths in different positions were conducted. The simulation and experimental results were discussed.

scholarly journals Study on design and fabrication of a prototype equipment used for corrosion inspection on petrochemical tank bottom by magnetic flux leakage method

2020 ◽  
pp. 280-288
Keyword(s):  
Magnetic Flux ◽  
Permanent Magnets ◽  
Low Cost ◽  
Scanning Speed ◽  
Magnetic Flux Leakage ◽  
Corrosion Pitting ◽  
Tank Bottom ◽  
Hall Sensors ◽  
Non Destructive ◽  
Flux Leakage

Corrosion of the bottom of the petroleum tank may lead to a product leak that could cause a fire or explosion resulting in damage to people and the environment, therefore the test of tank bottom corrosion is necessary to be conducted periodically to prevent the occurrence of the above problems. In non-destructive inspection, the Magnetic Flux Leakage (MFL) method relies on the variation of fluxes caused by defects on the surface of materials to detect corrosion, pitting, or imperfections, which is proved quite effectively with low cost. The project was implemented to develop a prototype of the MFL bottom detection device based on the research results in the world to improve corrosion survey capacity in industrial equipment, as well as to improve the expertise in the Research Team of electronics and automation in the fields of magnetic fields and sensors. As a result, an MFL model using permanent magnets and Hall sensors were fabricated. Survey experiments showed that the machine could detect corrosion defects up to 20% of steel wall thickness in the scanning speed range from 500 mm/s to 1130 mm/s. However, to meet the actual survey needs, the team must continue to improve the device in terms of sensitivity, scanning speed, the ability to operate automatically or semi-automatically, and register for a fire safety inspection.

Fault Localization of Power-Ground Short via Signal Injection and Oscilloscope Technique

2010 ◽  
Author(s):  
Binh Nguyen
Keyword(s):  
Low Cost ◽  
Short Circuit ◽  
Fault Localization ◽  
Fault Isolation ◽  
Test Apparatus ◽  
Good Working ◽  
Signal Injection ◽  
Set Up ◽  
Non Destructive ◽  
Short Circuit Condition

Abstract For those attempting fault isolation on computer motherboard power-ground short issues, the optimal technique should utilize existing test equipment available in the debug facility, requiring no specialty equipment as well as needing a minimum of training to use effectively. The test apparatus should be both easy to set up and easy to use. This article describes the signal injection and oscilloscope technique which meets the above requirements. The signal injection and oscilloscope technique is based on the application of Ohm's law in a short-circuit condition. Two experiments were conducted to prove the effectiveness of these techniques. Both experiments simulate a short-circuit condition on the VCC3 power rail of a good working PC motherboard and then apply the signal injection and oscilloscope technique to localize the short. The technique described is a simple, low cost and non-destructive method that helps to find the location of the power-ground short quickly and effectively.

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