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[IEEE 2018 28th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) - Greifswald (2018.9.23-2018.9.28)] 2018 28th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) - A Novel Vacuum Interruption Contact Design for High Current DC Vacuum Circuit Breaker
摘要： The vacuum interruption contact structure affect the insulation and breaking performance of DC vacuum circuit breaker directly. A novel vacuum interruption contact system with axial magnetic field (AMF)-double transversal magnetic field (TMF) is investigated for high current interruption in DC vacuum circuit breaker in this paper. It consists of one AMF cup-shaped contact and two concentric TMF contacts, which the internal contact is a disk-shaped structure and the external contact is a cup-shaped structure. The so-called novel TMF-TMF-AMF contact structure has the merits of having a very high axial magnetic flux density at large current condition, and producing rotation Lorentz force for metal vapor arc caused during interruption process. Its performance is compared with that of traditional TMF contact, traditional AMF contact and TMF-AMF contacts using three-dimensional finite-element method and the comparison results verify the validity of this proposed interruption contact structure design.
关键词： Lorentz force,vacuum interruption,finite element method,Axial magnetic flux density,metal vapor arc
更新于2025-09-23 15:23:52
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Three-Dimensional Scanning Hall Probe Microscopy for Final Stage of Crack Growth of Chromium Molybdenum Steel SCM440
摘要： Crack propagation around the stress concentration area causes fatigue failure. Non-destructive method is necessary for monitoring structure fatigue before destruction. We focused on a magnetic non-destructive evaluation method for crack growth. In order to understand the relation between crack propagation and changes in magnetic flux density, we observed the position of the positive and negative magnetic flux density distributions around the crack of tool steel (SCM440) plate using a scanning Hall probe microscope (SHPM). We found that the vertical component of the three-dimensional magnetic flux density moved as the crack growth. Furthermore, the magnetic component which is parallel to the tensile stress appeared just before destruction of the specimen.
关键词： Crack propagation,Scanning Hall probe microscope,Magnetic flux density
更新于2025-09-23 15:22:29
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Multistage Interband Cascade Thermophotovoltaic Devices with ~0.2 eV Bandgap
摘要： Detection of defects in induction machine rotor bars for disassembled motors are required to evaluate machines considered for repair as well as fulfilling incremental quality assurance checks in the manufacture of new machines. Detection of rotor bar defects prior to motor assembly are critical in increasing repair efficiency and assuring the quality of newly manufactured machines. Many methods of detecting rotor bar defects in unassembled motors lack the sensitivity to find both major and minor defects in both cast and fabricated rotors along with additional deficiencies in quantifiable test results and arc-flash safety hazards. A process of direct magnetic field analysis can examine measurements from induced currents in a rotor separated from its stator yielding a high-resolution fingerprint of a rotor’s magnetic field. This process identifies both major and minor rotor bar defects in a repeatable and quantifiable manner appropriate for numerical evaluation without arc-flash safety hazards.
关键词： magnetic flux,ac motors,electromagnetic measurements,induction motors,rotors,AC machines
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE International Conference on Space Optical Systems and Applications (ICSOS) - Portland, OR, USA (2019.10.14-2019.10.16)] 2019 IEEE International Conference on Space Optical Systems and Applications (ICSOS) - High Power Indium Phosphide Photonic Integrated Circuit for Pulse Position Modulation Free Space Optical Communications
摘要： Detection of defects in induction machine rotor bars for disassembled motors are required to evaluate machines considered for repair as well as fulfilling incremental quality assurance checks in the manufacture of new machines. Detection of rotor bar defects prior to motor assembly are critical in increasing repair efficiency and assuring the quality of newly manufactured machines. Many methods of detecting rotor bar defects in unassembled motors lack the sensitivity to find both major and minor defects in both cast and fabricated rotors along with additional deficiencies in quantifiable test results and arc-flash safety hazards. A process of direct magnetic field analysis can examine measurements from induced currents in a rotor separated from its stator yielding a high-resolution fingerprint of a rotor’s magnetic field. This process identifies both major and minor rotor bar defects in a repeatable and quantifiable manner appropriate for numerical evaluation without arc-flash safety hazards.
关键词： magnetic flux,ac motors,electromagnetic measurements,induction motors,rotors,AC machines
更新于2025-09-19 17:13:59
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Low-Light Image Enhancement with Semi-Decoupled Decomposition
摘要： Detection of defects in induction machine rotor bars for disassembled motors are required to evaluate machines considered for repair as well as fulfilling incremental quality assurance checks in the manufacture of new machines. Detection of rotor bar defects prior to motor assembly are critical in increasing repair efficiency and assuring the quality of newly manufactured machines. Many methods of detecting rotor bar defects in unassembled motors lack the sensitivity to find both major and minor defects in both cast and fabricated rotors along with additional deficiencies in quantifiable test results and arc-flash safety hazards. A process of direct magnetic field analysis can examine measurements from induced currents in a rotor separated from its stator yielding a high-resolution fingerprint of a rotor’s magnetic field. This process identifies both major and minor rotor bar defects in a repeatable and quantifiable manner appropriate for numerical evaluation without arc-flash safety hazards.
关键词： induction motors,ac motors,electromagnetic measurements,magnetic flux,AC machines,rotors
更新于2025-09-16 10:30:52
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Photovoltaic Module Fault Detection Using Integrated Magnetic Sensors
摘要： Fault detection and diagnosis of photovoltaic (PV) modules have become vital for reliable, efficient, and safe PV operating systems. This article proposes a new inspection method which is based on measuring the magnetic flux density on the surface of crystalline silicon PV modules. To measure the magnetic flux density generated around busbars of PV modules, their surfaces are scanned by two types of small integrated magnetic sensors for the one-dimensional (1-D) and 2-D magnetic profiles. This method enable us to detect different types of faults in PV modules, perform on-site measurements, and real time diagnosis. Since the measurement devices are composed of simple and small sensors, the overall cost of this method is very low as compared to other conventional fault detection methods.
关键词： photovoltaic (PV) module,Fault detection,magnetic flux density,magnetic sensor
更新于2025-09-12 10:27:22