High-Current Density Carbon Fiber Brush Experiments in Humidified Air and Helium

Metallized carbon fiber brushes capable of operating at up to 4.65 MA/m²(3000 A/in²) in an air environment have been developed, fabricated, and tested. Experiments in humidified air and helium gas atmospheres containing 50 to approximately 5000 ppm of water vapor have been undertaken. The results show that the total brush losses (electrical plus mechanical) are not substantially changed by the water vapor level, but the distribution of frictional and electrical losses is altered.