
Electric motors, generators, and related equipment can be seriously affected when electrical currents flow through their bearings.
This can lead to electrical erosion, damaging the rolling elements and raceways, and also causing the grease to break down more quickly.
The problem is made worse in systems that use frequency converters, which generate high-frequency currents due to stray capacitance.
SKF INSOCOAT bearings are engineered to block electrical current from passing through the bearing.
They feature an insulating layer of aluminium oxide on either the inner or outer ring, applied using an advanced plasma-spray technique to
ensure a high-quality finish. This solution offers a highly effective and economical alternative to other insulation methods.
Product Range
The standard range of SKF INSOCOAT bearings includes the most widely used sizes and versions of:
• Single row deep groove ball bearings
• Single row cylindrical roller bearings
Beyond the standard offering, SKF also provides customized INSOCOAT bearings and bearing units designed with more complex ring geometries, including:
• Four-point contact ball bearings
• Flanged tapered roller bearings
• Tapered roller bearing units (TBU)
• Traction motor bearing units
Key Features and Benefits
• Effective protection against electrical erosion
SKF INSOCOAT bearings incorporate insulating features directly into their design,
helping to significantly reduce the risk of electrical erosion.
This results in greater equipment reliability and extended operational uptime.
• High level of electrical insulation
The aluminium oxide coating ensures a minimum electrical resistance of 200 MΩ and can handle voltages of up to 3,000 V DC.
• Stable and reliable insulation performance
Since plasma-sprayed coatings tend to absorb moisture and may become susceptible to damage from condensation,
SKF INSOCOAT bearings are treated with a special sealant.
This treatment enhances resistance to moisture, ensuring consistent electrical insulation over time.

Application Areas
SKF INSOCOAT bearings are specifically engineered for use in applications where there is a risk of electrical current passing through the bearing,
which can lead to premature failure due to electrical erosion.
Typical application fields include:
• Railway traction systems: Mitigation of stray currents in traction motors and drive systems.
• Electric motors and generators: Prevention of bearing damage caused by shaft voltages, especially in inverter-driven systems.
• Wind turbines: Protection of generator bearings from high-frequency currents induced by variable-speed drives.
• Construction machinery: Enhanced bearing reliability in electrically powered or hybrid construction equipment.
• Industrial pumps: Insulation against potential circulating currents in electrically driven pump systems.
Further details, please ask our SKF expert team or explore our above-mentioned catalogues!