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Electrical Pitting

Electrical Pitting

Condition Cause Solution
  • Surface is speckled visually and the speckles are clusters of tiny pits when viewed through a microscope.
  • Further development leads to a corrugated surface.
  • Electric current passes through bearing, and sparks are generated to fuse the raceway surface.
  1. Avoid flow of electric current by averting current with a slip ring or insulation bearing.

Photo: Inner ring of cylindrical roller bearing

  • Inner ring of cylindrical roller bearing
  • Raceway surface is corrugated by electric pitting

Photo: Rollers of tapered roller bearings

  • Rollers of tapered roller bearings
  • Electric pitting at middle of rolling contact surfaces

Photo: Magnified (x400) pitting of roller shown in Photo 5

  • Magnified (x400) pitting of roller shown in Photo 5
  • Nital etchant develops a white layer on the cross section

Figure: Explanation of magnified photo 6

  • Explanation of magnified photo 6