Current Insulating Bearings

Deep groove ball bearings are often the standard for use in electric motors and other electric applications, but bearings exposed to electrical current can damage them. In high-current environments, the electrical current can damage both the raceways and rolling elements of deep groove ball bearings, which, in turn, can cause the motor or other application to fail prematurely and occasionally without warning. 

A motor failure can cause significant electrical damage and result in increased downtime. Current insulating bearings can help mitigate the damage done to deep groove ball bearings by preventing the bearing itself from the electric current. Current-insulating deep groove ball bearings can reduce downtime in electric motors and other electrical applications.

Understanding Current Insulating Bearings

Bearings with a ceramic coating in the inner or outer ring are current-insulated bearings. Essentially, a current-insulated bearing acts as a resistor and capacitor connected in parallel. The ceramic layer provides insulation against the passage of the electrical current through the bearing. Hybrid bearings, in which the rolling elements in a deep groove ball bearing are made from ceramic, also function as current-insulating bearings. 

The insulation helps the bearing to remain stable regardless of the operating conditions. As the ceramic coating does not conduct electricity, this non-conductive layer can give insulation to the bearing and prevent damage from electrical current. The higher the voltage the bearing will be exposed to, the greater the coating should be used to avoid damage.

Significance in Electrical Applications

Preventing electrical damage in rotating machinery should be of primary importance, as prevention can help avoid system failure and reduce the costs associated with machine downtime, production losses, and the expenses incurred for repairs. Using current insulating bearings from the planning stages and initial application construction will reduce maintenance repair costs, minimize downtime, and ensure continuous and reliable operation. 

As the current insulating bearings interrupt the electrical circuit between the housing and shaft, the bearings will show significantly higher resistance to damage caused by electrical current than standard deep groove ball bearings.

How Current Insulating Bearings Work

Damage to deep groove ball bearings and the application in its entirety usually presents initially as changes to the surfaces of the raceways. Dull, gray marks will appear on the raceways and rolling elements. “Fluting,” the washboard pattern that can develop along the raceway surface, indicates that an electrical current is passing through the bearing. 

Each time the rolling element encounters these craters, it becomes displaced, impacting the more pronounced vibration and, eventually, bearing failure. Electrical current can also break down the lubricant, causing the bearings to overheat during operation.

Current insulating bearings work by utilizing different non-conductive coatings to protect the operational elements of the bearings from this damage. These coatings provide electrical resistance and permit only deficient current levels to flow through the bearings. 

Ceramic coating is the most popular, but bearings that use ceramic rolling elements in place of or in addition to ceramic coating on the raceways, known as hybrid bearings, are also effective.

Applications and Industries 

Current insulating bearings are typically used in applications where reduced friction, lower wear, and increased potential of damage from electrical current are a concern. 

This can include:

• High-speed machinery
• Electric motors
• Fans
• Electrical pumps
• Household appliances
• Automotive components
• Generators
• HVAC applications

Using ceramic-coated bearings designed to insulate from electrical arcs and currents will increase the longevity of these applications. In addition, any application that relies on high speed and requires low friction will benefit from current-insulated deep groove ball bearings, as they have greater longevity and can enhance performance.

Considerations for Implementation

When selecting current insulating bearings for specific applications, it is essential to consider several factors that meet the application’s particular requirements. These typically include:

• Speed Requirements

High-speed applications often benefit from current-insulating bearings.

• Friction Requirements

Applications that require low friction need deep groove ball bearings that are resistant to damage from electrical current.

• Maintenance Considerations

Current-insulating deep groove ball bearings have lower maintenance requirements than traditional ones.

• Industry Standards and Regulations

Several industries have stricter regulations for materials and coatings required for operation. It is always essential to consider specific industry requirements to guarantee compliance.

Advancements and Future Trends

Reliability and reduced downtime have become more important to developers, with an increased demand for longevity and longer intervals between maintenance or component replacement. Research is ongoing to determine if the service life can be extended even further with more effective coatings. The HDY2 ceramic-coated bearings available from NSK are currently among the most effective at preventing electrical damage, with superior insulation properties and exceptional durability over conventional ceramic-coated bearings. 

Mitigate Electrical Damage with Insulating Bearings in Electrical Applications 

Current insulating bearings have a significant role in preventing damage to deep groove ball bearings in electrical applications. Their ability to insulate the bearing from the passage of electricity is exceptional at mitigating electrical damage and ensuring operational reliability. When you want to extend the life of your deep groove ball bearings in electrical applications, NSK’s HDY2 series ceramic-coated bearings deliver superior results. When reliability is non-negotiable, entrust NSK to provide the optimal solution for your deep groove ball-bearing requirements. Contact us today to learn more.