Full definition
Bearing with a dielectric coating on the outer (or inner) ring surface that interrupts the electric circuit and prevents fluting caused by stray currents in VFD-driven motors. Aluminum oxide (Al₂O₃) coating of 50–200 µm; resistance > 50 MΩ at voltages up to 800 V AC. Examples: SKF INSOCOAT (suffix VA228), FAG Megatex (J20AA). Alternative: ceramic hybrid bearings. Application: motors >200 kW with VFDs.