Wide strip hot rolling mill runout roll table electric drive control system
The object for the research is the electric drive of the wide strip hot rolling mill runout roll table. The goal of the research is decreasing the operational loses spent on the roll table equipment. The means for reaching the goal are the developing of the roll table equipment diagnostic system and the improved algorithm for electric drive control system. In the article the description of the performed researches and the results of developed systems applying are present.
Analysis And Development Of Electric Drives Automatic Adjustment Algorithms
The present article provides rationale for the necessity of automatic adjustment of the modern closed-loop systems of electric drives. The article gives a review of stages of the automatic adjustment and presents an experimental research of correlation between the required algorithms with real ones, which are applied in the typical industrial electric drives of different types. The characteristic of the symmetrical and modular optimums is given from the point of view of quality parameters of the electric drives control. The classification of current and speed loops adjustment in the relation to the symmetrical and modular optimums is given based on the experimental research. There are also recommendations given for improving the algorithms of the automatic adjustment for decreasing the time of commissioning the equipment.
ROOM- AND HIGH-TEMPERATURE MAGNETIC PROPERTIES OF Sm(CobalFexCu0.088Zr0.025)7.5 (x=0.30) SINTERED MAGNETS
The effect of Fe content on room- and high-temperature magnetic properties of Sm(CobalFexCu0.088Zr0.025)7.5 (x=0-0.30) sintered magnets, prepared by the conventional powder metallurgy method, has been systematically studied. With increasing Fe content, the remanences BT and maximum energy products (BH)max at room temperature gradually increase and reach optimal values of 1.055 T with x=0.27 for BT, and 205 kJ/m3 with x=0.21 for (BH)max, respectively, and then drop sharply with further Fe increase. An excessive addition of Fe (x≥0.24) results in rapid deterioration of permanent magnetic properties due to the formation of a considerable amount of FeCo soft magnetic phase. It was found that the effect of Fe content on high temperature stability is huge. The lower the Fe content, the smaller the temperature coefficient of coercivity. When x=0.07, a temperature coefficient of coercivity of -0.14%/K (293-723 K) can be achieved, as compared with -0.23%/K for x=0.21. BT of 0.725 T, bHc of 517 kA/m, iHc of 764 kA/m, and (BH)max of 95 kJ/m3 at 723 K were obtained, and the B-H demagnetization curve remains a straight line.