Epstein frame and single sheet tester are two methods used for measurement of power losses of the electrical steel sheets or strips. Both methods and the setups are described in the IEC standards. Each national metrology institute or other metrological laboratory has different setups for power losses measurement and the validation of its accuracy and parameters can only be done by comparisons. So far, every performed comparison was carried out only at 50 Hz or 60 Hz. Within the EMPIR project "HEFMAG", improved metrological infrastructure for the determination of power losses using Epstein frame at induction values close to saturation and at frequency ranges between 2 kHz and to 10 kHz was built. To validate the improved setups, a round robin comparison of power loss measurements was conducted by five laboratories. The results of the round robin comparison are discussed including measurement uncertainties.

This paper presents initial developments of the digital twin for the Garrett solenoid developed within the framework of 24RPT02 MetroMag project. The project aims to strengthen capabilities of European National Metrology Institutes (NMIs) in performing traceable measurements in the low magnetic field range. Garrett solenoid was identified as the most suitable for use as a traveling transfer standard between NMIs to enable easier and faster intercomparisons. The development of the digital twin of the Garrett solenoid will aid in documenting transfer standard, associated experimental setups and can aid in estimation of the uncertainty components in magnetic field metrology.

A rotation-based measurement technique, the locus constraint method, for determining the axis scale factors, offsets and non-orthogonality angles of three axis vector magnetometers was performed at a range of well-defined applied fields in a cancelled environment. The measured parameters are compared to well-established methods and locus constraint measurement performed in Earth's magnetic field. The scale factors obtained through the locus constraint method agree with established methods to within 0.02 % with an applied field of at least 30 mu T in a cancelled environment. The non-orthogonality angles measured are shown to reduce the difference between the outputs of a three-axis fluxgate magnetometer aligned for resultant and single axis indications from 0.043 % to 0.008 %. However, significant deviation in the measured axis offsets is seen between the two methods, similar to 20nT. The locus constraint method within a cancelled environment offers a higher accuracy than in Earth's magnetic field providing options for a calibration method which is cost effective while maintaining high accuracy.

Accurate characterisation of magnetic sensors is required across a range of industrial applications. The National Physical Laboratory (NPL), as the UK's National Metrology Institute (NMI), maintains and disseminates measurement standards, with traceability to SI units, that provides characterisation of advanced magnetic sensors from nT-level to several T. Space missions can benefit from the increasing sensitivity and accuracy of magnetic sensors. To calibrate such sensors, a low magnetic noise environment and traceable measurement systems must be established. Both spacecraft design and in-flight operation must rigorously incorporate magnetic cleanliness and compensate for field fluctuations. To reduce measurement uncertainties and dependent sensor error budgets, a greater understanding of the magnetic environment becomes crucial. This presentation will describe the development of traceable measurements systems at NPL that enable the characterisation of these sensors at the nT level for space applications. These systems allow key parameters, such as gain, linearity, offset and noise to be determined, with specific attention given to the measurement of the temperature dependance of these key parameters, and recent developments for the orthogonality of small magnetometers in a fast and cost-efficient way.

Magnetic steel is utilized in electric motors/generators and transformers, where the cyclic magnetization of the material results in notable energy losses. With the increasing emphasis on boosting energy efficiency, there is a demand for more effective evaluation methods to quantify these losses in challenging operational conditions involving high frequency, elevated temperatures, and also distorted flux conditions. This investigation seeks to assess the accuracy of techniques employed for measuring losses in thin steel sheets, as well as in nanocrystalline and ferrite materials. The evaluation extends beyond the established IEC 60404 standards by broadening the ranges of induction, frequency, and temperature. These measurements play a pivotal role in advancing magnetic materials and power electronics devices, facilitating the development of materials with enhanced energy performance in practical operating scenarios. Consequently, this supports the application of the Ecodesign Directive 2009/125/EC and contributes to the attainment of objectives outlined in the United Nations 2030 Agenda for Sustainable Development.

Main text The results of the supplementary comparison in the area of magnetic field probe calibration of the field strength are presented. This supplementary comparison has been discussed to organize a comparison on magnetic field strength measurements during the EURAMET TC-EM Subcommittee Radiofrequency and Microwave (SC-MW) meeting, including an EMC meeting, organized as a virtual (online) meeting on 20-21 April 2021. The comparison was conducted in accordance with the Technical Protocol of "Comparison of Magnetic Field Strength Measurements for Frequencies up to 30 MHz, EURAMET Project No 1538, EURAMET.EM.RF-S46", which was prepared by the TÜBİTAK UME and approved by the participants. The measurements started in January 2022 and were completed in May 2023. Measurement results reported by nine participants for magnetic field strength values were compared and degrees of equivalence are reported. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

We investigate the temperature dependence of the energy loss $W(f)$ of 0.10 and 0.20 mm thick Fe-Co-V sheets (Vacoflux Ⓡ and Vacodur Ⓡ) in the range −50 °C $\le T \le155 ^{\circ }\text{C}$ . The measurements, performed from DC to ${f}$ = 5 kHz on ring samples and Epstein strips, show that $W(f)$ passes through a minimum value around room temperature at all tested polarization values ( $1.0\le J_{\mathrm {p}} \le1.9$ T). The largest effect occurs under quasi-static regime and declines with frequency, depending on the sheet thickness and the ensuing role of the dynamic loss. The somewhat abnormal increase of the quasi-static loss $W_{\mathrm {hyst}}$ with temperature, which contrasts with a concurrent decrease of the magnetocrystalline anisotropy constant, is interpreted in terms of temperature-dependent internal stresses and their change with $T$ . The stresses are assumed to derive from the different thermal expansion coefficients of the ordered and disordered structural phases, a conclusion made plausible by the highly magnetostrictive properties of the material, dwelling in a low anisotropy environment. The AC properties are treated by adapting the loss decomposition to the inception and development of a non-uniform induction profile across the sheet thickness (skin effect) at high frequencies. The classical loss component is calculated via the numerical solution of the Maxwell’s diffusion equation, where the magnetic constitutive equation of the material is identified with the normal magnetization curve. It turns out that the so-found $W_{\mathrm {class}}(f)$ and the resulting excess loss $W_{\mathrm {exc}}(f)$ are moderately dependent on temperature and $W(f)$ eventually tends towards a slow monotonical decrease with ${T}$ at the highest frequencies.

Main text The COOMET.EM-S26 (1715) supplementary comparison of national standard instruments in the field of magnetic flux density and magnetic flux measurements by sensing coils has been organized within the CCEM framework to test the abilities of the metrology institutes to measure magnetic flux density and magnetic flux. Five NMIs participated in the supplementary comparison COOMET.EM-S26 (1715). Ural Research Institute for Metrology (UNIIM) (since 2020 it has been called Affiliated Branch of D.I. Mendeleev Institute for Metrology (VNIIM-UNIIM)), Russian Federation, acted as the coordinating laboratory of the comparison. The comparison on DC magnetic flux density and magnetic flux was carried out through the measurement of the coil constant of transfer standard coils. In general, very good agreement of the results has been observed. To reach the main text of this paper, click on Final Report . Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/ . The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Integrity assessment of pipelines is vital to ensure that oil and gas pipes have adequate strength to prevent leaks and ruptures. Regular inspections are conducted to confirm safe operation conditions of pipelines. The industry's principle method for assessing pipelines is in-line inspection (ILI), involving the passing of a device along the inside of a pipe to assess the condition of the pipeline. ILI devices can be fitted with a number of sensors allowing various measurement parameters to be obtained simultaneously. Not all pipelines are suited to ILI for reasons such as small diameter, obstructions within the pipe, or insufficient access to deploy or retrieve the ILI tools. These pipelines are sometimes referred to as 'difficult to inspect'. Alternative methods for examining pipeline condition are required with a range of technologies collectively known as Large Standoff Magnetometry (LSM) offering a promising solution for detection of pipe defects from a distance, reducing the need for excavation. LSM utilises coupling between defects and changes in the magnetic properties of the pipeline material as a method for evaluation of pipe walls to identify the location of areas that require repair or further monitoring. Trials of existing commercial instruments by the pipeline industry have shown sufficient promise to investigate these technologies further. However, the vendors have supplied limited information on the underpinning physics of both the materials being tested and the instrument technology, meaning that further study is required in order to build confidence in the technique. The purpose of the project is to establish the ability of LSM to detect corrosion in API 5L pipe grades B to X70. The aim of Work Package 04 is to measure the magnetic fields of a range of pipe samples containing manufactured corrosion flaws taking into account variables such as standoff distance, pressure, nearby ferromagnetic objects, position of the corrosion flaw around the pipe, track alignment, and orientation with respect to Earth's magnetic field. The results of these measurements will be used to validate computational models, which can be used to predict the magnetic response of a wider range of pipe geometries.

Integrity assessment of pipelines is vital to ensure that oil and gas pipes have adequate strength to prevent leaks and ruptures. Regular inspections are conducted to confirm safe operation conditions of pipelines. The industry's principle method for assessing pipelines is in-line inspection (ILI), involving the passing of a device along the inside of a pipe to assess the condition of the pipeline. ILI devices can be fitted with a number of sensors allowing various measurement parameters to be obtained simultaneously. Not all pipelines are suited to ILI for reasons such as small diameter, obstructions within the pipe, or insufficient access to deploy or retrieve the ILI tools. These pipelines are sometimes referred to as 'difficult to inspect'. Alternative methods for examining pipeline condition are required, with a range of technologies collectively known as Large Standoff Magnetometry (LSM) offering a promising solution for detection of pipe defects from a distance, reducing the need for excavation. LSM utilises the coupling between defects and changes in the magnetic properties of the pipeline material as a method for evaluation of pipe walls to identify the location of areas that require repair or further monitoring. Trials of existing commercial instruments by the pipeline industry have shown sufficient promise to investigate the technologies further. However, vendors have supplied limited information on the underpinning physics of both the materials being tested and the instrument technology. The purpose of the project is to establish the ability of LSM to detect corrosion in API 5L pipe grades B to X70. The aim of Work Package 02 is to review the physics of the agreed pipeline defects and fluxgate type magnetic sensors. The properties of pipeline-specific soft magnetic materials are investigated to understand corrosion, how this alters the material properties and how this can affect the associated magnetic fields surrounding the material. The physics of fluxgate magnetometers and gradiometers are also reviewed to assess the ability of LSM to detect these two features.

High-power inductive power transfer (IPT) systems for charging light and heavy electric vehicles pose safety concerns if they are installed in uncontrolled environments. Within the framework of the European Project EMPIR-16ENG08 MICEV, a wide experimental and numerical study was conducted to assess the exposure of the general public to IPT stray magnetic fields for two different exposure scenarios: (1) for an IPT model system derived from the SAE J2954 standard operating at 85 kHz for a light electric vehicle coupled with the model of a realistic car-body model; and (2) for an IPT model system with a maximum rated power of 50 kW at 27.8 kHz for a real minibus that was reproduced with some simplifications in two different 3D finite element method (FEM) simulation tools (Opera 3D and CST software). An ad hoc measurement survey was carried out at the minibus charging station to validate the simulations of the real bus station for both aligned and misaligned IPT coils. Based on this preliminary study, a safety factor was chosen to ensure a conservative dosimetric analysis with respect to the model approximations. As highlighted in this study, the vehicle-body serves as an efficient screen to reduce the magnetic field by at least three orders of magnitude close to the coils. By applying FEM, computed spatial distribution to the Sim4Life software, the exposure of three Virtual Population human anatomical phantoms (one adult, one child, and a newborn) was assessed. The three phantoms were placed in different postures and locations for both exposure scenarios. The basic restriction limits, established by the current guidelines, were never exceeded within the vehicles; however, the basic restrictions were exceeded when an adult crouched outside the minibus, i.e., near the coils, or when a newborn was placed in the same location. Borderline values were observed in the light car. In the case of the bus, limits coming from the Institute of Electrical and Electronics Engineers (IEEE) guidelines are never exceeded, while basic restrictions coming from the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines are exceeded up to 12% for an adult and up to 38% for a newborn. This paper presents novel dosimetric data generated in an IPT system for heavy vehicles and confirms some of the literature data on light vehicles.

The European Union funded project MICEV aims at improving the traceability of electrical and magnetic measurement at charging stations and to better assess the safety of this technology with respect to human exposure. The paper describes some limits of the instrumentation used for electrical measurements in the charging stations, and briefly presents two new calibration facilities for magnetic field meters and electric power meters. Modeling approaches for the efficiency and human exposure assessment are proposed. In the latter case, electromagnetic computational codes have been combined with dosimetric computational codes making use of highly detailed human anatomical phantoms in order to establish human exposure modeling real charging stations. Detailed results are presented for light vehicles where, according to our calculations, the concern towards human exposure is limited. Currently, the project has reached half way point (about 18 months) and will end in August 2020.

This paper describes the characterisation of an optical tracking system that allows to accurately locate the position of a magnetic sensor used for measuring the magnetic field generated from inductive charging of electrical vehicles. This paper forms part of the metrology for inductive charging of electric vehicles (MICEV) project. 2D measurements have been successfully carried out with the optical tracking system and the data acquisition has been automated by means of a dedicated software routine. The experimental setup, results, data and uncertainty analysis are presented in this paper. We show that the expanded uncertainty of the tracking system is ±0.64 mm with a coverage factor k = 2, providing a coverage probability of approximately 95%.

Corrosion is a central problem for the oil and gas and nuclear industries, affecting pipelines and nuclear waste storage tanks. Reliable methods for timely corrosion detection and integrity evaluation are needed for a range of industrial structures where corrosion under insulation manifests as wall loss. Commercially available detection systems cannot be used in harsh nuclear-storage environments. Moreover, these systems are not reliable for detecting the inner wall thickness of industrial structures made of multiple layers of material, including insulation layers. A novel nondestructive testing method based on low-frequency eddy-current induction was developed and tested on a multilayered steel structure, including an insulating gap. The method enables through-wall thickness measurements between 4 and 16 mm, with a measurement error of 1 mm. The technique is quantitative, nondestructive, and allows the sensor coil to be positioned on the outside of the composite steel structure, which is useful when the interior of an industrial container or pipeline is not accessible.

Selective Laser Melting (SLM), a powder-bed Additive Manufacturing technology, can be used in combination with high temperature post-annealing to produce high-silicon steel parts characterised by quasi static magnetic properties comparable to those of commercial electrical steel. However, the role of the as-built microstructure on the magnetic properties is still unexplored. Therefore, in this study the effect of the energy input of the processing laser on the magnetic properties of the material is investigated. The magnetic properties are determined for 4 mm-high rings obtained using three laser energy input values that provide a good compromise in terms of porosity and crack formation. The best magnetic properties are obtained for the rings built using a value of energy input that produces a strong fibrous crystallographic texture, in which one of the crystallographic <001> axes is preferentially aligned along the build direction. Whether the magnetic properties change with sample direction as a result of the crystallographic texture will be the subject of future research.