SKF
INSOCOAT Bearings
INSOCOAT bearings from SKF are rolling bearings with an aluminium oxide coating applied to the external surfaces of the outer or inner ring. This ceramic-like coating provides excellent electrical insulation, preventing the passage of damaging current through the bearing. Designed to combat electrical erosion in electric motors and generators, INSOCOAT bearings can be used instead of hybrid bearings where the insulation requirement is on the bearing seat rather than through the rolling elements. Available on deep groove ball bearings, spherical roller bearings, cylindrical roller bearings, and others, the coating is thin, durable, and resistant to moisture and chemicals. INSOCOAT bearings are a reliable, cost-effective solution to the pervasive problem of bearing currents in large industrial electric machines operating with variable frequency drives or design-induced shaft voltages.
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Outer/Inner Ring Insulation
Al2O3 coating insulates> 1000 V DC, preventing current flow.
Preserves Standard Bearing Internals
Same rolling elements and cage as standard bearings.
Moisture and Chemical Resistant
Coating does not absorb water or degrade in aggressive environments.
No Speed or Load Restrictions
Insulated ring does not affect mechanical ratings.
Eliminates Fluting and Frosting
Stops electrical erosion damage on raceways.
Cost-Effective Insulation
Lower cost than hybrid bearings for certain motor sizes.
INSOCOAT vs. Hybrid Bearings: Which Insulation to Choose
INSOCOAT prevents current from passing through the bearing by insulating the housing or shaft interface. Hybrid bearings insulate through the rolling elements. INSOCOAT is suitable when shaft current path is through the bearing outer ring and housing; hybrid is more universal and offers additional speed benefits.
Typical Applications: Large AC Motors and Generators
High-voltage motors and generators often have significant shaft voltages due to magnetic asymmetries. SKF INSOCOAT spherical roller bearings in these machines prevent the circulating currents that would otherwise cause rapid bearing failure, improving plant availability.