Measurement and Interpretation of the Effect of Electrical Sliding Speed on Contact Characteristics of On-Load Tap Changers

This paper analyzes the effect of sliding speed on electrical conductivity and friction properties contact pair an on-load tap changer (OLTC). Reciprocating current-carrying tribological tests were carried out a rod–plate–copper–tin–copper galvanic couple at different speeds in air insulating oil media. The results show that as increases from 24 mm/s to 119 mm/s, average resistance 0.2 ? 0.276 ?, also 0.267 ?. At maximum reaches 0.3 micro-topography images obtained by scanning electron microscopy with increase speed, wear mechanisms are mainly abrasive adhesive wear, layered erosion craters; high arcing promote surface fatigue crack generation. X-ray photoelectron spectroscopy was used analyze surface. copper oxide cuprous sulfide cause film resistance, total accordingly. In addition, test shows 95 thresholds. Below these thresholds, is caused mechanical wear. Above arc chemical oxidation processes. Non-mechanical factors exacerbate deterioration become main factor for resistance.