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NTN MEGAOHM Series Insulated Single Row Cylindrical Roller Bearings

NTN MEGAOHM Series Insulated Single Row Cylindrical Roller Bearings mark a significant step forward in bearing technology. They are specifically engineered to fight the damaging effects of stray electrical currents. These bearings are vital for machinery where current leakage poses a risk. As key components in the Electrically Insulated Cylindrical Roller Bearings family, the MEGAOHM Series stands out. It offers excellent insulation and a robust design.

Defending Against Electrical Pitting

Electrical pitting is a common issue in bearings used in electrical systems such as motors and generators. When stray current flows through a bearing, it creates microscopic arcs that damage the raceway and rolling elements. These sparks form tiny craters or flaking on the surface, which deteriorates the structural integrity of the bearing. Over time, this leads to increased vibration, noise, and ultimately, premature failure of the bearing.

The NTN MEGAOHM Series Insulated Single Row Cylindrical Roller Bearings are specifically engineered to address this issue. By incorporating an insulating layer—made of either ceramic or resin—on the outer ring, the bearing disrupts the electrical path and effectively eliminates current flow through the rolling elements. This design not only prevents spark erosion but also reduces the risk of system downtime and equipment damage caused by unexpected bearing failure.

Ceramic vs Resin Insulation

The NTN MEGAOHM Series offers flexibility through its two insulation types: ceramic-coated and resin-coated. These options are designed to meet different industrial needs based on voltage level, temperature, environmental exposure, and cost considerations.

Ceramic insulation is ideal for high-voltage applications and extreme environments. It offers excellent electrical resistance and is highly stable at elevated temperatures. Ceramic coatings are also resistant to chemical corrosion and mechanical wear, making them well-suited for harsh environments such as railway traction motors and wind power systems.

On the other hand, resin insulation provides a cost-effective solution with excellent insulating performance for standard industrial applications. It is lightweight, easier to apply during production, and can still maintain insulation resistance over 100 MΩ at 500 VDC. Resin-insulated bearings are suitable for general-purpose electric motors where conditions are stable but electrical isolation is still essential.

Global Applications and Standard Compatibility

NTN MEGAOHM Series Insulated Single Row Cylindrical Roller Bearings are engineered to meet the demands of industries that require both mechanical strength and electrical insulation. Typical application areas include:

Traction motors in railway systems, where reliability and insulation under vibration are critical
Wind turbines, which operate in fluctuating environmental and electrical conditions
Industrial electric motors used in pumps, compressors, and HVAC systems

These bearings are manufactured in accordance with globally recognized standards such as ISO 492, DIN 620, and JIS 1514. This ensures interchangeability, quality consistency, and compatibility across a wide range of industrial machines.

Bore diameters range from 50 mm to 160 mm, covering the needs of compact equipment as well as large power systems. Whether it’s for upgrading existing equipment or designing new machinery, these bearings are a dependable choice.

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FREQUENTLY ASKED QUESTIONS

What is electrical pitting, and why does it harm bearings?

Electrical pitting happens when stray electrical currents go through a bearing. This causes tiny electrical sparks or discharges between the rolling parts and raceways. These sparks damage the bearing locally. Over time, these small pits build up. They make the surface rough, increasing friction, noise, and vibration. This eventually harms the bearing's performance and greatly shortens its life. If not fixed, it often leads to early failure.

How does the MEGAOHM Series perform in harsh environments?

MEGAOHM bearings are designed to remain stable under extreme conditions, including high temperature, strong vibration, and fluctuating voltage. The ceramic insulation layer can resist thermal breakdown and mechanical stress, while the resin option provides excellent resilience and insulation stability in moderately demanding conditions. This makes MEGAOHM bearings suitable for traction motors, mining equipment, offshore platforms, and renewable energy systems. Their robust insulation ensures consistent performance in both static and dynamic electrical environments.

Does the insulation affect the mechanical performance of the bearing?

No, the insulation layer is applied only to the outer ring and does not interfere with the rolling elements or the internal geometry of the bearing. As a result, the bearing maintains its radial load capacity, high rotational speed, and minimal friction. MEGAOHM bearings still deliver all the mechanical benefits expected of a cylindrical roller bearing, while adding the critical benefit of electrical protection.

Are NTN MEGAOHM bearings easy to integrate into existing systems?

Yes. These bearings are designed with standard dimensions and are fully compatible with international bearing series. They follow ISO, DIN, and JIS specifications, making them easy to replace or integrate without needing structural changes to equipment. Engineers can upgrade existing machinery by using MEGAOHM bearings to improve insulation performance without redesigning the entire system.