Hall, M J; Patel, H V; Lin, A*; He, J* (2012) Comparison of permanent magnet measurements. Report on values measured using methods compliant with IEC 60404 part 5 and Pulse Field Magnetometers. NPL Report. MAT 54

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Abstract

An IEC TC 68 comparison on the measurement of the magnetic properties of permanent magnets was completed in 2009. NPL and NIM Beijing were the coordinators and NPL performed the analyses and wrote the reports. With permanent magnets being used in safety critical situations it is necessary to perform 100% quality control at the operating temperature. An established method using an electromagnetic to measure the demagnetising curve is not practical for these measurements due to the time taken, the difficulty in raising the temperature and the operator skill required. A Pulsed Field Magnetometer (PFM) has been developed that can determine the full BH curve in as little as 10 ms. By comparing measurement made using electromagnet and pulse methods the influence of the dynamic effects of the latter could be established. It was found that for the technology significant parameter of intrinsic coercivity a significant difference exist between the methods. Further research is needed to understand the magnetic viscosity that contributes to this before the PFM method can be considered further for adoption as a standard method.

Item Type:	Report/Guide (NPL Report)
NPL Report No.:	MAT 54
Subjects:	Advanced Materials Advanced Materials > Magnetic Materials
Last Modified:	02 Feb 2018 13:14
URI:	http://eprintspublications.npl.co.uk/id/eprint/5352

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