No abstract

A ferrometer with compensation conversion intended for plotting hysteresis loops of soft-magnetic materials is discussed. The ferrometer consists of a magnetization module, two identical magnetic induction and field intensity measuring channels, a control microprocessor, and a display module. The operating principles and metrological characteristics of the ferrometer are described.Most information on the properties of soft-magnetic materials (SMM) is provided by hysteresis loops and their parameters. The coordinates of the hysteresis loop points are converted with an analog-digital converter into coupled digital code pairs stored and processed in a microprocessor. The implementation of this method requires quite complex and expensive automatic systems [1]. Another method is to use instruments based on the ferrometric approach [2]. These instruments are relatively simple and inexpensive. The F5063 ferrometer formerly manufactured in the Ukraine belongs to them. No such instruments are now manufactured in Russia. At the same time, they are very useful since by measuring hysteresis loops one can easily find many characteristics and parameters of SMMs.As is well known [2], the ferrometric method consists in phase-sensitive rectification of signals from the magnetizing and measuring coils of the investigated SMM sample and subsequent averaging to find the instantaneous field intensity and magnetic induction of the sample. In the simplest case, this can be done by connecting in series [2] a controlled analog switch and a low-pass filter, i.e., by direct conversion of the measured signal including all its shortcomings, the most important of them being the addition of the errors of all individual units. Here we describe an instrument that measures the coordinates of points for plotting hysteresis loops and is free from many defects of classical ferrometers.The compensating ferrometer (CF) [3] uses a modification of the ferrometric method which is based on the fact that the integral of the derivative of a periodic (period T) odd function, averaged of the period (beginning at the time ti), is equal to the negative instantaneous value of this function at the time ti:

No abstract

No 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...