What is bearing fluting and what prevention steps can be taken?

Bearing fluting is a common issue in the industrial machinery industry. This issue can commonly be found in motors and generators. The cause of fluting is caused by electrical discharges when the lubricant film breaks down. When the film breaks down, this allows a current to arc across the bearings rolling elements, and raceway.

So what exactly causes fluting? The issue mainly occurs in motors and machinery using VFDs (Variable Frequency Drives). Stray electrical currents will travel through the motor shaft and into the bearings. This creates an arcing gradually eroding the bearings’ surfaces. Most occurrences are in motors where voltage build-up between the rotor and the stator exceeds the insulating capacity of the lubricant.

Are there any causes that a technician or operator might notice? Yes, the smooth motion of the bearing rolling elements will cause a noise along with vibration. Catastrophic bearing failure may occur if the issue isn’t handled in a timely matter.

How can fluting be prevented? There are several measures that can be taken to prevent bearing fluting. See below:

1) Proper Grounding: Check the motor or generator shaft is correctly grounded to prevent stray currents from passing through the bearings.
2) Shaft Grounding Rings: Install shaft grounding rings. These will redirect stray currents away from the bearing.
3) Bearing Isolators: The use of bearing isolators will protect the bearings from contaminants and electrical discharges.
4) Regular Maintenance: Conduct regular maintenance checks to identify any signs of bearing fluting to prevent catastrophic failures.
5) Insulated Bearings: Ceramic hybrid bearings can be used to prevent electrical discharges from reaching the surfaces of the bearing.

Implementing the above practices will greatly reduce the risk of bearing fluting on your watch. If you have any questions or need assistance, we would love to assist you in any way. Reach out with any questions to one of our representatives today. We can deliver parts to your job site or meet with you to identify what issues are occurring and assist you with a solution.