E. Hristoforou, E. Kayafas
ON THE MAGNETIC AND MAGNETOELASTIC UNIFORMITY MEASUREMENTS OF MAGNETOSTRICTIVE RIBBONS AND FIBERS

In this paper we present results on magnetic and magnetoelastic uniformity measurements of magnetostrictive ribbons and fibers. Both magnetic and magnetoelastic measurements are based on the magnetostrictive delay line (MDL) response. Measurements were realized by using an automatic instrumentation device, with parametric control of field and frequency. The device has been calibrated with respect to standard Ni wires. Indicative results are given concerning amorphous magnetostrictive ribbons and fibers, showing a good agreement with other measuring techniques.

Marcos Flavio de Campos
ANISOTROPY OF STEEL SHEETS AND CONSEQUENCE FOR EPSTEIN TEST: I THEORY

ODF – Orientation Distribution Function – Theory allow the prediction of the average magnetic properties of electrical steels when crystalline symmetry of cubic bcc iron and the orthorhombic sheet symmetry are taken into account. The crystallographic texture can be related to the magnetocrystalline anisotropy by means of a very simple expression. The dependence of the variables: Magnetic Induction, coercivity, permeability and iron losses with texture is discussed. Magnetic Induction at high fields - B₂₅ and B₅₀ - can be directly scaled to magnetocrystalline anisotropy. Effects of demagnetizing field on the Magnetic Induction are commented. Permeability and power losses are not directly related to magnetocrystalline anisotropy, mainly due the existence of domain wall displacement phenomena. The domain wall structure is function of the crystalline orientation and also contributes for the anisotropy of iron losses. As consequence of the theoretical analysis, it is suggested that the traditional Epstein arrangement (50% RD-Rolling Direction plus 50% TD–Transverse Direction), be changed for 3 separate measurements in the RD, TD (i.e., 90o) and 45° directions.

Pasquale Arpaia, Juan Garcia Perez, Alessandro Masi, Giovanni Spiezia
METROLOGICAL CHARATERIZATION OF A FAST DIGITAL INTEGRATOR FOR MAGNETIC MEASUREMENTS AT CERN

A Fast Digital Integrator (FDI) was designed to satisfy new more demanding requirements of dynamic accuracy and trigger frequency in magnetic measurements based on rotating coil systems for analyzing superconducting magnets in particle accelerators. In particular, in flux measurement, a bandwidth up to 50-100 kHz and a dynamic accuracy of 10 ppm are targeted. In this paper, results of static and dynamic metrological characterization of the FDI prototype and of the Portable Digital Integrator (PDI), heavely used at CERN and in many sub-nuclear laboratories, are compared. Preliminary results show how the initial prototype of FDI is already capable of both overcoming dynamic performance of PDI and covering operating regions inaccessible before.

Hüseyin Çayci, Özlem Yilmaz, Burak Ayhan, Tansu Kefeli, Mustafa Günes, Erol Kazanç
AC POWER MEASUREMENT SYSTEM OF UME

A high accuracy power measurement system, based on digital sampling techniques, has been developed and evaluated for the power frequencies at UME (National Metrology Institute of Turkey). The system is based on two sampling voltmeters and a phase-locking device. Using of a precision voltage transformer and a current transformer with a shunt resistor, and reducing the synchronizing errors results in an uncertainty of 20 ppm for active, reactive and apparent power measurements for power frequencies.

Lech Hasse, Lech Loroch, Krzysztof Rogala, Ludwik Spiralski
MEASUREMENT OF THIRD HARMONIC FLUCTUATIONS FOR A PASSIVE COMPONENT UNDER LARGE PERIODIC BIAS

The noise (fluctuation) level and non-linear distortions can be established as a new criteria for selection of passive elements for different endurance (sustainability) and reliability groups. Measurement of third harmonic (TH) fluctuations and its implementation into the production testing system have been proposed. It can improve the process of quality estimation of high reliability elements.