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
Parameters
Parameter
J20AB
J20AA
J20C
Puncture voltage
1000 VDC
3 000 VDC
3 000 VDC
Operating
environment
Dry, damp
Dry, damp
Dry, damp
Layer thickness
100 um
200 um
200 um
Possible
dimensions
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
Operating
environment
Dry
Dry
Layer thickness
≤100 um
>200 um
Possible
dimensions
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