Improved systems for the measurement of hysteresis loops: DC and AC characterisation
01 Jul 1987-Journal of Physics E: Scientific Instruments (IOP Publishing)-Vol. 20, Iss: 7, pp 861-865
TL;DR: In this paper, two low-cost measurement systems that use active circuits in the power stage are proposed for the DC and AC characterisation of industrial soft and/or hard ferromagnetic materials.
Abstract: Two low-cost measurement systems that use active circuits in the power stage are proposed for the DC and AC characterisation of industrial soft and/or hard ferromagnetic materials. For the DC measurements, the discrete variation of the point-by-point method is simulated by a very low frequency triangular wave. The problems encountered are pointed out and the solution proposed is tested experimentally. The AC source system combines a power amplifier and an operational amplifier with a feedback technique. This allows the option of selecting the power source to be either a constant voltage or a constant current source. Results obtained using these methods on a core sample of mild steel are shown to bring out the performance of the system.
TL;DR: In this article, the authors proposed a method to measure dynamic hysteresis loops of magnetic samples by using a high speed digital voltmeter, where all data are immediately displayed by computer-compatible techniques.
Abstract: Proposes measurement of dynamic hysteresis loops of magnetic samples by the use of a high speed digital voltmeter. The advantage of this method is that a simple and accurate automatic measuring device may be built up, where all data are immediately displayed by computer-compatible techniques.
•01 May 1983
TL;DR: In this article, the power factor and losses due to sinusoidal MMF are computed for square, circular, and rectangular rods using a rectangular B/H curve and the results are normalised and given in a table from which many computation steps can be saved.
Abstract: Eddy-current losses due to sinusoidal MMF are computed for square, circular, and rectangular rods using a rectangular B/H curve. for all sections, it is assumed that the induced currents flow on a path parallel to the sides. The results are normalised and given in a table from which many computation steps can be saved. The saturating induction is chosen as the value of B which corresponds to a quarter of the applied magnetic field on the magnetisation curve. The validity of the hypothesis is confirmed by measurements made on 15 rings, constructed from mild steel, cast iron and special magnetic alloys. The power factor and losses are usually predicted within 10% for a field ranging from 200 to 70000 A/m. Resume: Les pertes par courants de Foucault dans des tiges circulaires, carrees et rectangulaires sont analysees dans l'hypothese d'une courbe de magnetisation rectangulaire et sous I'influence d'une FMM sinusoidale. Ceci conduit a une onde flux qui penetre le materiau et qui y induit des courants paralleles a la surface externe. Les pertes et le facteur de puissance sont calcules et presentes sous forme de tableau. L'induction de saturation est choisie comme etant egale a I'induction correspondante au quart du champ magnetique maximum applique. Une serie de resultats experimentaux sur quinze noyaux montre que la theorie s'applique dans une large gamme de conditions: champs magnetiques de 200 a 70 000 A/m, pertes de 5 a 70 000W/m2 et materiaux tels que la fonte et I'acier doux.
TL;DR: In this paper, some new active circuits using active circuits are proposed for realization of sinusoidal flux in a ferromagnetic core during loss testing, which facilitates the loss measurements to be made from the primary side itself.
Abstract: Some new schemes using active circuits are proposed for realization of sinusoidal flux in a ferromagnetic core during loss testing. One of the suggested configurations facilitates the loss measurements to be made from the primary side itself. A few filter circuits enable the tests to be carried out on normal supply mains without the need for a calibration generator. Experimental results are reported to confirm the acceptability of the proposed schemes.