Comparison of Carbon Brush Sliding Characteristics with Copper Ring and Steel Ring in Large Alternate Rotating Machine

Abstract

In the case of high speed and large capacity AC machines, such as turbine generators and large synchronous motors for industrial use, steel collector rings are generally applied to the brush/ring operation, where higher reliabilities are required, especially for large machines when compared to small machines. The brush/ring operation failures directly cause the service operation to shut down. Although steel ring application to those machines has been successful for almost sixty years, at present no one knows why “steel” is applied to the collector ring. It is considered that steel ring application technologies have never been disclosed or studied. In this study, the following points are investigated.1) Consistency analysis for steel ring application2) Experimental analysis for brush spark and collector ring hazard3) Experimental analysis for brush contact V-I characteristicsThe above-mentioned points help in improving the reliabilities of the brush/collector ring operation, where the results of steel ring are completely compared with these of copper ring.