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The use of melt-textured Y-Ba-Cu-O in magnetic bearings and electric motors is discussed.

A new material was studied for high-efficiency motor cores that need higher magnetic flux density, lower iron loss, and lower mechanical hardness. Excessively high Si content tends to decrease magnetic flux density of nonoriented electrical steel sheets. The composite addition of rare-earth metals (REM) and AI into molten steel was found to make inclusions coarse and remarkably improve grain growth during stress relief annealing, which resulted in decreased iron loss. A new nonoriented electrical steel sheet (50RMA350) with Si, Al, and REM has been successfully developed to give a higher efficiency to inverter drive model motors than a conventional material. Index Terms - Aluminum, iron loss, magnetic flux density, motor, nonoriented electrical steel sheet, rare-earth metals, silicon.

This paper looks at brush life, why brushes wear, and what can be done to achieve longer brush life. It is meant to provide one with an understanding of the factors and conditions that contribute to brush wear in order that problem areas can be avoided and existing problems identified and resolved. This, however, is not an instruction manual on how to fix problems. The motor manufacturer should be contacted for help in resolving brush and commutation problems. The following applies to medium- and large-horsepower industrial dc motors and generators. Index Terms--Brush current density, brush wear, commutator film, motor brushes, motor commutators.