[Zurück]

J. Dudding, P.A. Knell, R.N. Cornelius, B. Enzberg-Mahlke, W. Fernengel, R. Grössinger, M. Küpferling, P. Lethuillier, G. Reyne, M. Taraba, J.C. Toussaint, A. Wimmer, D. Edwars:
"A pulsed field magnetometer for the qualitiy control of permanent magnets";
Journal of Magnetism and Magnetic Materials, 242-245 (2002), S. 1402 - 1404.

A pulsed field magnetometer for the qualitiy control of permanent magnets

J. Dudding [Corresponding Author Contact Information] , [E-mail The Corresponding Author] , a, P. A. Knella, R. N. Corneliusa, B. Enzberg-Mahlkeb, W. Fernengelc, R. Grössingerd, M. Küpferlingd, P. Lethuilliere, G. Reynef, M. Tarabad, J. C. Toussainte, A. Wimmerd and D. Edwardsg

a Hirst Magnetic Instruments Limited, Tesla House, Tregoniggie, Falmouth, Cornwall TR11 4SN, UK
b Magnetfabrik Schramberg, Schramberg-Sulgen, Germany
c VAC, Hanau, Germany
d Inst. f. Experimentalphysik, Techn. Univ. Vienna, Austria
e CNRS, PO BOX 166X Grenoble, France
f Univ. Ensieg LEG, Saint-Martin D'Heres, France
g Mecelec Developments Limited, Gloucester, UK

Available online 18 December 2001.

Abstract

A pulsed field magnetometer (PFM) for industrial applications was developed. The system has a capacitor bank of 5 mF for energy storage, which can be charged up to 3000 V. The pulse magnet has a bore of 30 mm (including the pickup coil), which is subdivided into two coils and produces a maximum field of 5 T with pulse frequencies of 17.5 and 25 Hz. The magnetisation is measured with a well balanced and temperature stabilised coaxial pickup system. The signal is integrated with a stable analogue integrator with selectable time constants. The signals are connected to a 14bit 5M sample/s two-channel ADC in a computer. For the data handling a C++-based computer program was written. The effects of eddy currents on the metallic samples are corrected by using the so-called f/2f method. Here two hysteresis measurements with two different time constants are used to measure the eddy current error. The function and reliability of the system is demonstrated by measuring the hysteresis of standard permanent magnets in the PFM and in a static system.

Author Keywords: Magnetic measurement; Hysteresis loop; Eddy currents

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