PT-Level High-Sensitivity Magnetic Sensor with Amorphous Wire

He, Danqing

doi:10.3390/s20010161

Cited by 10 publications

(9 citation statements)

References 25 publications

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“…The NDT methods are used in a broad area of applications, from the construction engineering [1] up to the aerospace area [2,3]; however, the limiting factors are the knowledge and technical equipment. The use of the methods also depends on the development of materials, sensors, sensing principles, visualization and interpretation of the measured quantities and values [4][5][6]. Specific area of the NDT is formed around the approaches utilizing low frequency magnetic fields, properties, effects and ongoing dynamic processes.…”

Section: Introductionmentioning

confidence: 99%

“…The NDT methods are used in a broad area of appl from the construction engineering [1] up to the aerospace area [2,3]; however, the factors are the knowledge and technical equipment. The use of the methods also d on the development of materials, sensors, sensing principles, visualization and i tation of the measured quantities and values [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

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Low-Frequency Magnetic Fields in Diagnostics of Low-Speed Electrical and Mechanical Systems

et al. 2021

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The magnetic field created by technical devices is a source of information. This information could be used in contactless diagnostics and predictive maintenance or for resolving problems along with standard NDT (nondestructive testing) methods, especially if we consider large, slow-speed devices, such as electromotors, transmissions, or generators. Identification of causalities of device failure processes with near magnetic field is one of the suitable NDT methods improving sustainability of systems. The measurements presented in the article were performed with the VEMA 04 fluxgate vector magnetometer with the DC-250 Hz bandwidth and 2 nT sensitivity. Postprocessing of the results was performed in the means of standard methods of discrete Fourier Transform, spectrogram creation and Wavelet Transform. The article presents data gathered during the measurement of a pair of extraction fans with power of 140 kW each and maximum revolutions up to 740 rev/min controlled by frequency converters and a single semi-Kaplan water power plant with 400 kW peak power at 1005 rev/min maximum generator speed. The measurements were performed before and after repairs of one of the ventilators in the ventilation system at 60% and 100% of maximal output power. The rotating magnetic fields of the fan electromotor stator, fan rotor revolutions, rotor slip frequency and ball-bearing frequencies were identified in frequency spectrums in the distance of 700 mm from fan electromotor axis in both cases. During the measurements on the semi-Kaplan turbine, the changes in states of mechanical and electrical components of the machine were monitored in the magnetic fields with increase of the power in the range of 0–95%, before and after phasing to the electrical grid. Standard processing methods, Discrete Fourier Transform, spectrograms and Discrete Wavelet Transform were used. In the spectrograms of the measured magnetic fields, the 1st–4th harmonics of the turbine shaft, generator shaft and also their side frequencies were identified. Significant changes of magnetic fields in time were identified in the area of 60–95% power. With the help of the Wavelet, transform intervals were identified where it is desirable to operate the turbine. The analyses of magnetic fields measurements performed on the power plant were compared with vibro-diagnostic principles.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Low-Frequency Magnetic Fields in Diagnostics of Low-Speed Electrical and Mechanical Systems

et al. 2021

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“…The high-sensitivity magnetic sensors using a coil with the (Fe 0.06 Co 0.94 ) 72.5 Si 2.5 B 15 (FeCoSiB) amorphous wire as the core were reported [17][18][19] and the white noise spectrum of about 6 pT/√Hz was achieved. Different from normal MI sensors, the amorphous wire of this kind of magnetic sensor had no any electrical connection with the cable.…”

Section: Introductionmentioning

confidence: 99%

Developing Gradiometer to Reduce the Low Frequency Noise of Magnetic Sensor with Amorphous Wire

He¹

2021

JEEE

Self Cite

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Pico-Tesla level high sensitivity magnetic sensor has been developed using FeCoSiB amorphous wire as the core of a coil, but the low frequency noise of the magnetic sensor is somewhat high, and some applications of magnetic sensors, such as magnetic microscope or deep defect detection, require that the sensors have low noise at low frequency. To reduce the noise, it is necessary to know the noise sources of the magnetic sensor. By measuring the noise spectrum of each part of the magnetic sensor with FeCoSiB amorphous wire was measured, it was found that the white noise of the magnetic sensor was mainly determined by the noise of the preamplifier and the low frequency noise was mainly determined by the low frequency noises of the DC bias current and AC bias current of the FeCoSiB magnetic sensor. To reduce the low frequency noise of the magnetic sensor caused by the bias current noise, an electrical gradiometer composed of two magnetic sensors sharing the same DC bias current and AC bias current was developed. The results proved that the gradiometer was not only effective to reduce the low frequency noise caused the bias current, but also effective to reduce the environmental noise caused by the 50 Hz line interference. Using the gradiometer, an eddy current testing (ECT) system were constructed, and the deep defect with the depth of about 8 mm in an aluminum plate was successfully detected by the ECT system.

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“…The first sensor application of amorphous wire was the GMI sensor [20,21], where the high-frequency impedance of the wires depends on the DC field that is applied, due to a change in the magnetic permeability. GMI sensors can detect fields down to the nT range, noise level of 35 pT/ √ Hz at 1 Hz has been recently reported [22]. GMI sensors based on amorphous wire have reversible and reproducible stress sensitivity [23].…”

mentioning

confidence: 98%

Modelling and Measurement of Magnetically Soft Nanowire Arrays for Sensor Applications

Ripka

Grim

Mirzaei

et al. 2020

Sensors

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Soft magnetic wires and microwires are currently used for the cores of magnetic sensors. Due to their low demagnetization, they contribute to the high sensitivity and the high spatial resolution of fluxgates, Giant Magnetoimpedance (GMI), and inductive sensors. The arrays of nanowires can be prepared by electrodeposition into predefined pores of a nanoporous polycarbonate membrane. While high coercivity arrays with square loops are convenient for information storage and for bistable sensors such as proximity switches, low coercivity cores are needed for linear sensors. We show that coercivity can be controlled by the geometry of the array: increasing the diameter of nanowires (20 µm in length) from 30 nm to 200 nm reduced the coercivity by a factor of 10, while the corresponding decrease in the apparent permeability was only 5-fold. Finite element simulation of nanowire arrays is important for sensor development, but it is computationally demanding. While an array of 2000 wires can be still modelled in 3D, this is impossible for real arrays containing millions of wires. We have developed an equivalent 2D model, which allows us to solve these large arrays with acceptable accuracy. Using this tool, we have shown that as a core of magnetic sensors, nanowires are efficiently employed only together with microcoils with diameter comparable to the nanowire length.

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PT-Level High-Sensitivity Magnetic Sensor with Amorphous Wire

Cited by 10 publications

References 25 publications

Low-Frequency Magnetic Fields in Diagnostics of Low-Speed Electrical and Mechanical Systems

Low-Frequency Magnetic Fields in Diagnostics of Low-Speed Electrical and Mechanical Systems

Developing Gradiometer to Reduce the Low Frequency Noise of Magnetic Sensor with Amorphous Wire

Modelling and Measurement of Magnetically Soft Nanowire Arrays for Sensor Applications

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