FAG ceramic-coated bearings (current-insulating)

FAG ceramic-coated bearings are standard bearings in which either the inner ring or outer ring has the ceramic coating Insutect.

Nodes supplies FAG ceramic-coated bearings, include deep groove ball bearing with coated oute ring or inner ring, cylindrical roller bearing with coated outer ring.

FAG ceramic-coated bearings

FAG bearings with the Insutect coating have the following advantages:

High insulation protection:

Bearings with oxide ceramic coating are identified by the suffix (J20). These layers are applied to the bearing surfaces using the plasma spray method. The oxide ceramic layer is very hard, resistant to wear and has good thermal conductivity.

The insulation J20AB gives excellent protection against current passage due to induced voltage along the shaft. Due to a special sealing process, the J20AB coating achieves an insulating effect even in damp environments.

The insulation J20AA is applied to the outer ring and is twice as thick as the J20AB coating. It therefore gives additional security even at higher frequency current.

The thickness of the J20AA insulation is the same as the insulation J20C. In this case, however, the inner ring is coated. Since the coated surface is smaller, it gives even better protection against high frequency currents. It is particularly suitable in applications with high frequency currents and a rotating outer ring.

The Insutect family is completed by the insulations J20B and J20A, which are used in special cases where simpler protection (J20B) or special protection principally for large diameters (J20A) is required. Please refer to the figure below.

U = puncture voltage
s = coating thickness

The external dimensions of the current-insulated rolling bearings correspond to the dimensions in accordance with DIN 616 (ISO 15). FAG Current-insulated bearings are therefore interchangeable with standard bearings.

FAG coated deep groove ball bearings are available in series 62 and above. In addition to the open design, the variants are available with lip seals on one or both sides. As a result, the user can run the lubricated-for-life bearing for even longer. In addition, a range of special types are possible.

The coating method

In the plasma spray method, an electric arc is generated between two electrodes and the inert gas introduced is ionised. The resulting plasma jet is then used as the carrier jet for the aluminium oxide powder. This is melted and sprayed at high velocity onto the inner or outer ring. The oxide layer thus applied has excellent adhesion to the base material, which must be roughened in advance. The oxide layer is then sealed.

Dielectric breakdown strength

The coatings are subjected to 100% quality inspection and ensure a dielectric breakdown strength of at least:

  • J20AB as insulation up to 1000 VDC
  • J20AA, J20C as insulation up to 3 000 VDC
  • J20B as insulation up to 500 VDC.

Below this voltage, the insulating layer allows only very small flows of current through the FAG bearing.

Types of coatings and value ranges


Parameter J20AB J20AA J20C
Puncture voltage 1000 VDC 3 000 VDC 3 000 VDC
Dry, damp Dry, damp Dry, damp
Layer thickness 100 um 200 um 200 um
70 mm – 1400 mm
outside diameter
70 mm – 500 mm
outside diameter
70 mm – 340 mm
inner ring bore

Parameter J20B J20A
Puncture voltage 500 VDC 1 000 VDC
Dry Dry
Layer thickness ≤100 um >200 um
70 mm – 1400 mm
outside diameter
70 mm – 500 mm
outside diameter

The FAG bearing surfaces of the rings to be coated must be cylindrical and must not be interrupted by lubrication holes or grooves.

How to ordering FAG ceramic-coated bearings

Ordering example:
Deep groove ball bearing with coated outer ring, sealed on both sides
Radial internal clearance C3

Ordring desination: 6220-2RSR-J20AA-C3

Cylindrical roller bearing with coated outer ring
Radial internal clearance C4

Ordring desination: NU214-E-M1-F1-J20B-C4

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