Reduction of Particle Growth Rate and Slip-Ring Assembly Segmented Rings

A study was conducted to determine a method of reducing particle growth rate between slip-ring assembly (SRA) brushes and segmented rings. The particles from the SRA were analyzed using a scanning electron microscope (SEM) to determine the formation mechanism. An X-ray fluorescence analysis of the particle revealed its material composition. Three approaches were then considered as the most likely to alter the growth rate: burnishing the conductive segments, altering the quantity of lubricant on the segmented rings, and modifying the brush forces. The materials, tools, and techniques for these three approaches were developed in conjunction with weighing the advisability of pursuing each approach to reduce the particle growth rate. After the reduced brush-force approach had been selected, a time-lapse 16-mm movie film was made of particle development over five days at 1 frame/min for 317 000 slip-ring revolutions. The film compares growth rates of brush and ring groups set at preselected brush-force ranges. The segmented-ring brush-force range was thereby determined; then SRA's were modified and retested, with positive results.