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  • NKE insulated bearings

Electrically Insulated Bearings

Optimum protection against bearing damage caused by the passage of currents

NKE electrically insulated rolling bearings reliably prevent current discharge.

NKE provides bearings with oxide ceramic insulating layers on the bearing ring. Applied with plasma technology, the insulation has a guaranteed breakdown resistance of at least 1000V AC or DC. Two variants are available:

  • SQ77: Insulation on the outer ring
  • SQ77E: Insulation on the inner ring

Typical applications

  • Traction motors of railway vehicles
  • Electric motors (AC/DC)
  • Generators (e.g. in wind turbine generators)

Product range

SQ77(insulated outer ring)

  • Cylindrical roller bearings
    • Design variants: NJ, NU, NUP
    • Dimension series: 210-230, 310-330
    • Cages: brass and polyamide
    • Radial clearance groups: C0, C3, C4
  • Deep groove ball bearings
    • Dimension series: 6212-6226; 6312-6326
    • Cages: brass
    • Radial clearance groups: C3, C4
  • Other types and SQ77E (insulated inner ring) upon request


  • Higher operational reliability through optimum protection against electrical corrosion
  • More economic than, for example, insulation on housings or shafts
  • Interchangeable: Same key dimensions and technical properties as conventional bearings
  • Coating resistant to damage if correctly handled