FAG Ceramic-Coated Bearings: Superior Protection Against Electrical Erosion
In modern industrial applications, rolling bearings used in traction motors, electric motors, and wind power generators are frequently exposed to the threat of current passage. If left unprotected, electrical discharge can cause severe damage to raceways and rolling elements, including melt craters, welding beads, and fluting. To combat these issues, Schaeffler offers a comprehensive range of FAG current-insulated bearings, with FAG ceramic-coated bearings serving as a primary preventive solution.
FAG ceramic-coated bearings are standard bearings enhanced with a specialized oxide ceramic coating known as Insutect.
Schaeffler provides several Insutect coating generations tailored to specific electrical and environmental requirements:
- J20AB (Standard Protection): Applied to the outer ring, this coating provides a dielectric breakdown strength of up to 1000 VDC. It is specifically designed to prevent damage from induced voltage along the shaft.
- J20AA (Premium High-Frequency Protection): Also applied to the outer ring, this layer is twice as thick as J20AB, offering a puncture voltage of up to 3000 VDC. It provides additional security against high-frequency currents.
- J20C (Inner Ring Protection): By coating the inner ring with a 200 μm layer, the coated surface area is minimized, resulting in lower capacitance. This variant offers the best possible protection against high-frequency currents, especially in applications like wind power generators.
- J20B & J20A: These are specialized coatings used for lower voltage requirements (500 VDC) or very large bearing diameters (above 500 mm).
Key Advantages for Machine Availability
Integrating FAG ceramic-coated bearings into your system design offers significant technical and economic benefits:
- Full Interchangeability: The external dimensions of these bearings conform to DIN 616 (ISO 15) standards, allowing them to directly replace non-insulated standard bearings without any mechanical modifications.
- Extended Service Life: By stopping the flow of current, these bearings prevent lubricant degradation (oxidation and cracking) and physical surface damage, thereby reducing maintenance costs and increasing machine availability.
- Reliable Electrical Resistance: At operating temperatures (60°C to 80°C), these bearings maintain a resistance of several MΩ, ensuring that current flow remains at non-critical levels (significantly below 1 mA).
Typical Applications
FAG current-insulated bearings are the industry standard for high-stakes electrical environments:
- Rail Vehicles: Tapered roller bearings with J20B coating for axlebox arrangements or J20AA for traction motors.
- Industrial Motors: Deep groove ball bearings with J20AB coating on the fan side to interrupt shaft current circuits.
- Wind Power: High-capacity deep groove ball bearings with J20C inner ring coating to withstand high-frequency discharges.
By selecting FAG ceramic-coated bearings, you ensure that your equipment is protected by one of the most reliable and field-proven technologies in electrical insulation.