TAILIEUCHUNG - Handbook of Lubrication part 13

Tham khảo tài liệu 'handbook of lubrication part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Volume II 483 FIGURE 10. Electrical pitting in tin-base babbitt produced by high current. Magnification X 15. From Boyd J. and Kaufman. H. N. Lubr. Eng. 15 1 28 1959. With permission. FIGURE 11. Electrical pitting in tin-base babbitt produced by low current. Magnification X 15. From Boyd J. and Kaufman H. N. Lubr. Eng. 5 1 28 1959. With permission. Regardless of their size electrical pits have a characteristic appearance. The bottoms are rounded and have a smooth shiny melted appearance Figure 10 . Usually the periphery of the pit at the bearing surface has a ridge of melted metal. In some cases this ridge is worn away by contact with the journal. For cases in which wiping damage has been superimposed electrical pitting can be identified as the cause by examining the harder journal surface which operated against the bearing. Copyright 1983 CRC Press LLC 484 CRC Handbook of Lubrication FIGURE 12. Principal sources of bearing current in rotating machinery. From Boyd J. and Kaufman H. N. Lubr Eng. 15 1 28 1959. With permission. Figure 12 shows schematically some sources of bearing currents in rotating machinery. Table 1 reviews these sources and methods of eliminating or reducing the bearing currents. Because bearing currents may be produced by a variety of conditions no single method of measuring potentials is suitable in all cases. Table 1 indicates the best location for taking measurements. In the case of the dissymmetry effect measuring the potential between the shaft and one bearing may be unreliable. This is because both bearings are in series with the generated emf and a temporary large resistance in the one bearing may make the potential across the other bearing negligible. The most reliable method is to measure the potential between the extremities of the shaft. Using this method on ordinary electrical apparatus with Copyright 1983 CRC Press .

TỪ KHÓA LIÊN QUAN
Đã phát hiện trình chặn quảng cáo AdBlock
Trang web này phụ thuộc vào doanh thu từ số lần hiển thị quảng cáo để tồn tại. Vui lòng tắt trình chặn quảng cáo của bạn hoặc tạm dừng tính năng chặn quảng cáo cho trang web này.