https://ukmagsoc.org/events/magnetisation-measurement/
Hirst’s Pulse Field Magnetometry and Open to Closed Measurement Technologies
by John Dudding, Robin Cornelius, & James Clewett of Hirst Magnetics
Hirst’s history of practical, innovative magnetising and material parameter testing techniques is coupled to its long term aim of reinterpreting the open magnetic circuit measurements of magnet materials. Hirst’s 25 year development of Pulse Field Magnetometry (PFMs) led to the writing of IEC Technical Report TR62331 and is currently leading the international team working on the new International Standard IEC 60404 part 18 detailing the PFM technique. Hirst has overcome many of the perceived limitations of the PFM technique but the ultimate goal has always been to use the PFM technique to provide accurate, repeatable and fast Permeameter, (BH Tracer,) closed circuit like results for engineering and quality control. As well as a brief overview of its magnetising technologies which have also made progress, Hirst will describe the workings of PFMs, the limitations of the Permeameters and also its new PFM process*, enabling Open to Closed (O2C**) measurements of rare earth permanent magnet material and finished magnets in industrial shapes. This process enables, fast, repeatable measurements, between +210 °C and -40 °C with an accuracy currently under a confirmation review in an active joint project with the National Physical Laboratory (NPL) Open to Closed measurement is expected to open a new era in the magnetic measurement of magnetic materials at a time when efficiency is powering our Green Technology revolution. Shaped pre magnetised components will at last have a pre-assembly and pre magnetisation QA capability. Patent applied for. ** Registered Trade Mark
