Automatic recorder of static hysteresis loops in magnetically hard materials

Abstract

1. The experimental investigation of precision obtained in the equipment for recording hysteresis loops of magnetically hard materials has shown that it is inadvisable to calibrate it by means of a ballistic installation, since the errors of the two methods are of the same order. A theoretical analysis indicates that the total error of the newly developed equipment amounts to 1.5%. 2. The labor consumed in recording hysteresis loops with the new equipment is considerably smaller than that of the ballistic installation. The recording and processing time does not exceed 5 min. At present the new installation is semiautomatic, since it requires manual trimming of the magnetizing current wave-form. Complete automation of the hysteresis-loop recording is considered possible on the basis of the produced model and experimental criteria. 3. The equipment is suitable for recording quasistatic hysteresis loops. The measuring unit drift and the integration constant are suitable for studying specific remagnetization cycles and their position with respect to the basic magnetization curve. 4. The sensitivity and precision of the measuring unit are adequate for studying the effect of temperature on the static characteristics of ferromagnetic materials. The utilization of inductive transducers does not limit the temperature range. 5. The wave-form of the magnetizing current makes it possible to reduce the nominal power of the current sources (dynamoelectric generator) and decrease the size of the electromagnets.