The metrological characteristics of automated magnetic measuring systems

Abstract

Automated systems for precision measurements of the magnetic characteristics and parameters of samples of soft magnetic materials at'(, considered. A list of their metrological characteristics is proposed.Precision measuring instruments are required to check magnetic measuring apparatus and to certify standard samples of the magnetic properties of soft magnetic materials. Automated magnetic measuring systems are being increasingly used for this purpose. They consist of an interconnected set of software and hardware, which enables a considerable volume of magnetic characteristics and the parameters of samples of soft magnetic materials of different shapes to be determined when they are magnetized under different conditions [ t ]. A feature of such systems, which, according to [21, are problem measuring-computing systems, is the program control of the test process, which requires the necessary presence of a controlling computer in the measuring system. This enables one to achieve different modes of testing a sample, and enables one to select and measure the required magnetic quantities with high accuracy.Questions of metrology when measuring the dynamic characteristics and parameters of soft magnetic materials in the audiofrequency band are regulated by the State Standard GOST 12119-80 [3]. Since these standards were laid down, the apparatus employed for magnetic measurements has advanced considerably. Hence, the requirements of this standard require considerable updating and supplementation as they apply to automated magnetic measuring systems.The purpose of this paper is to provide a list of metrological characteristics of automated magnetic measuring systems.Since the main purpose of automated magnetic measuring systems is to check working means of magnetic measurements and to certify standard samples of soft magnetic materials, the requirements imposed on the errors when measuring magnetic quantities are extremely high. Table l shows the acceptable errors in measuring the fundamental magnetic quantities, according to [3], and the errors which standard samples and the means of measurement for certifying them must have (including automated magnetic measuring systems) ill accordance with the criterion of negligibly small error.It can be seen from the data in Table l that the errors in measurin~ ma.netic quantities usin. standard measuring instruments should not exceed 0.2-0.3%. At the same time, the best standard samples of soft magnetic materials have considerable error. Thus, the set of standard samples of dynamic magnetic properties MS-6 [4], produced at the D. I. Mendeleev All-Union Scientific Research Institute of Metrology, and designed to reproduce the total losses, the fundamental magnetization curve and dynamic hysteresis loops in units of magnetic flux and magnetomotive force in the 50 Hz -10 kHz frequency band, has an error not greater than 0.5%. It should be noted that the errors in determining the geometrical dimensions of the ring cores of standard samples do not occur in this error. The standard sam...