What’s the Difference Between VL0241 and VL2071 Coatings?

Should the insulating coating be applied to the inner ring (VL2071 series) or the outer ring (VL0241 series)?

The VL2071 series applies the coating to the inner ring, resulting in lower insulation capacitance compared to the outer ring insulated VL0241 series. In motors driven by high-frequency PWM signals generated by inverters, this lower capacitance offers more effective insulation impedance, providing a distinct advantage in suppressing high-frequency shaft currents.

This article will detail the differences between SKF VL0241 and VL2071 insulated coated bearings and introduce how TFL provides ideal alternatives with superior quality and customized services.

Summary

• VL0241 (Outer Ring Insulated): Suitable for applications with lower shaft voltage and limited installation space. Coating thickness is approximately 100 µm, with a breakdown voltage typically ≥ 1000 V DC.
• VL2071 (Inner Ring Insulated): Superior for tackling high-frequency shaft currents and better in humid or oily environments. Coating thickness is approximately 100 µm, also providing insulation performance of ≥ 1000 V DC.
• TFL Alternative Solution: Offers fully compatible electrically insulated deep groove ball bearings, cylindrical roller bearings, and tapered roller bearings, as well as customization services. Insulation breakdown voltage can reach up to 3000 V, with a resistivity of ≥ 200 MΩ, all at a significant cost-benefit.

SKF VL0241: Ideal Application for Outer Ring Insulated Bearings

SKF VL0241 represents the standard layer insulation coating applied to the outer ring surface. This design excels in specific operating conditions by effectively blocking the current path.

Technical Features and Applicable Scenarios:

• Coating Location: Outer surface of the outer ring. This makes the insulation layer less susceptible to damage during bearing installation, especially in applications where the motor housing serves as a reliable ground.
• Coating Thickness and Insulation Performance: The VL0241 coating thickness is typically around 100 μm. In dry conditions, its insulation withstand voltage can reach 1000V DC, effectively preventing electrical erosion damage to the bearing raceway caused by motor shaft currents.
• Application Environment: Suitable for applications where the shaft voltage is relatively low and where the current is primarily conducted through the bearing housing. Examples include standard induction motors, small wind power generators, and certain pump equipment.
• Installation Advantage: Outer ring insulation avoids potential damage to the inner ring coating during installation, simplifying the assembly process.

TFL VL0241 Equivalent Alternative:

TFL offers electrically insulated deep groove ball bearings, cylindrical roller bearings, and tapered roller bearings, all of which provide a completely interchangeable outer ring insulation solution with SKF VL0241. Our ceramic coating uses advanced plasma spraying technology, resulting in a uniform and dense coating that ensures an insulation withstand voltage of ≥1000V DC and maintains stable insulation performance throughout its life cycle. Tests show that TFL’s outer ring insulated bearings can maintain an insulation resistance of over 50 MΩ at 1000V, far exceeding industry standards.

SKF VL2071: Advantages and Selection of Inner Ring Insulated Bearings

SKF VL2071 signifies a standard insulation coating applied to the inner ring surface. This configuration demonstrates its unique value in applications requiring stronger current-blocking capability or in more complex environments.

Technical Features and Applicable Scenarios:

• Coating Location: Outer surface of the inner ring. Inner ring insulation more effectively breaks the current loop when there is a large potential difference between the shaft and the bearing housing, or when the shaft current flows directly through the shaft to the bearing inner ring.
• Coating Thickness and Insulation Performance: Similar to VL0241, the VL2071 coating thickness is also approximately 100 μm, providing an insulation withstand voltage of ≥1000V DC. In motors driven by inverters, due to common-mode voltages generated by high-frequency PWM signals, inner ring insulation can better cope with high-frequency shaft currents.
• Application Environment: Widely used in large motors, VFD motors, wind turbine main shafts, rail transit traction motors, and other demanding applications with higher insulation requirements. In environments with oil, moisture, etc., which might compromise the effectiveness of outer ring insulation, inner ring insulation offers more reliable protection.
• Installation Consideration: Installation of inner ring insulated bearings requires more careful handling to avoid damage to the coating.

TFL VL2071 Equivalent Alternative and Customization Service:

TFL’s inner ring insulated bearings—whether deep groove ball, cylindrical roller, or tapered roller types—can provide the equivalent insulation effect of the SKF VL2071. Our manufacturing process and material selection ensure excellent adhesion between the coating and the substrate, with superior impact resistance and wear resistance.

How to Choose Between VL0241 and VL2071

TFL Insulated Bearings: The Advantage of Customization

TFL not only provides standard model electrically insulated bearings that are alternatives to the SKF VL0241 and VL2071 deep groove ball bearings, cylindrical roller bearings, and tapered roller bearings, but also focuses on customization services. This means we can adjust the coating thickness, insulation material formula, and even provide hybrid ceramic bearing solutions for special operating conditions based on your specific needs.

A large wind farm frequently experienced electrical erosion failures in its main shaft bearings. After introducing TFL’s customized insulation solution, by increasing the insulation coating thickness from a standard 150 μm to 250 μm and optimizing the coating material, the bearing service life was successfully extended to three times its original duration, saving the customer hundreds of thousands of dollars annually in maintenance and downtime losses.

By choosing TFL electrically insulated bearings, you select not only a high-quality product but also an efficient and reliable solution.

Send an email to info@insulated-bearings.com or click the pop-up window in the sidebar to contact our team of experts. Let us customize the most suitable electrically insulated bearing for your operating conditions, and together, we will enhance equipment reliability and operational efficiency!

FAQ

What is the difference between VL0241 SKF and VL2071 SKF coatings?

VL0241 coating is applied on the outer ring, suitable when the outer ring is stationary (e.g., electric motors). VL2071 coating is applied on the inner ring, suitable when the shaft is grounded or the outer ring rotates (e.g., traction or wind turbine motors).

What is the insulation resistance of VL0241 SKF and VL2071 SKF bearings?

VL0241 SKF typically offers ≥200 MΩ, while VL2071 SKF provides ≥100 MΩ at 500V DC testing voltage. TFL’s replacements offer ≥250 MΩ, ensuring longer insulation stability in humid or contaminated environments.

Will the ceramic coating affect the bearing’s fit or tolerance?

No. After ceramic spraying, TFL bearings undergo precision grinding and measurement correction, maintaining ISO 492 class tolerances.

Will the insulation coating peel off under vibration or heat?

No. TFL uses high-adhesion plasma spraying and performs 300-hour salt spray and thermal shock tests to ensure coating stability up to 200°C.

What materials are used in the insulation coating?

TFL coatings mainly use Al₂O₃ (aluminum oxide) ceramic, with optional TiO₂ or MgO additives for higher dielectric strength or corrosion resistance.