Mathematical Model of Contact Resistance for Brush and Slip Ring System Considering the Impact of Marine Environment

The working environment of carbon brushes and slip rings in marine applications is extremely harsh, as salt spray deposition alters the contact surface and significantly affects contact resistance. To accurately evaluate the electrical contact performance of carbon brushes and slip rings, it is essential to establish a mathematical model of contact resistance. The main influencing factors include salt spray concentration, sliding speed, contact current, and contact pressure. In this study, the variation trends of dynamic contact resistance with respect to these four factors were investigated through experiments, and the corresponding mechanisms were analyzed. The results show that contact resistance increases consistently with rising salt spray concentration, and the trend continues upward. It also increases gradually with higher sliding speed. Conversely, contact resistance decreases gradually as contact pressure increases. Similarly, an increase in contact current leads to a gradual decrease in contact resistance. Based on the experimental results, a sliding electrical contact resistance (ECR) model incorporating salt spray concentration, sliding speed, contact current, and contact pressure was developed. The findings confirm that the proposed model can be used to predict sliding ECR under various marine working conditions.