Solving Premature Bearing Failures

If you notice problems with your bearings, it’s important to act quickly before you experience a bearing failure. Once you know what’s causing the problem, there are a variety of steps you can take to prevent premature bearing failure. 

Solving early bearing failures requires you to first diagnose the root cause. There are several common causes for bearing failure, including lubrication issues, contamination trouble and a problem with excess magnetic energy.

Lubrication

If you’re having trouble with your bearings, they may need more or different lubrication. Many bearing problems occur because they aren’t able to move as freely as they need to — often, lubrication is enough to solve this problem. 

For an optimal lifespan, bearings need to be lubricated frequently. It’s important to ensure you’re using the right kind and the proper amount of lubricant to expand your bearings’ useful life. Too much lubricant can also clog up the bearings and cause issues. 

Contamination

Sometimes, dirt, sand and other small particles can get into the bearing assembly. If this happens, the bearings may bind up due to corrosion or damaged surfaces. Contaminants in the assembly can also cause a lubricant problem. 

Bearing seals help keep unwanted elements out of the bearing assembly. Any time you touch the bearing assembly, it’s important to protect it from foreign matter. If you’re concerned that separable bearings have been contaminated, you can dismantle the assembly to clean it.

Destructive Currents

Bearing failure may be caused by an electrical issue. When industrial equipment is running, it sometimes creates excess electrical energy in the form of a magnetic field. This is similar to static, and it needs somewhere to go. 

Typically, this type of energy looks for a grounding path — which it often finds through the bearings. Over time, this can cause etching that degrades the surface and eventually leads to bearing failure.

How to Protect Bearings From Destructive Currents

There are many potential solutions to this issue. One option is to invest in ceramic bearings, which don’t react to excess current in the same way as typical bearings. However, this fix takes time and money, and it’s not a permanent solution. Here are two better options for your operation:

Shaft Grounding Rings

Shaft grounding techniques offer a mechanical solution to this electrical issue. Grounding rings do not get rid of destructive currents. They simply provide a path to the motor casing so this energy doesn’t damage the bearings. Here’s more about how shaft grounding rings work:

• Grounding rings must be replaced each time anything is changed inside the motor, like installing new bearings.
• To work effectively, the shaft must remain clean from contaminants. Any kind of oil, grease or corrosion inside the shaft will disrupt the fibers from sending currents into the ground.
• Some systems require special supporting equipment on the non-load side of the motor.
• Grounding rings require one product per motor. One example is that a simple wall of fans driven by one drive requires all motors to have a grounding ring.

If the electric motor casing is improperly grounded, stray current will go into another important part of the system. However, as long as grounding rings are maintained, they will protect your bearings. 

Over time, these mechanical grounding rings are susceptible to external contamination, which results in little to no effectiveness for shaft current grounding.

Inductive Absorber Technology

To offer a better solution, experts in the industry have been experimenting with inductive absorption technology.

Absorbers are an electrical solution where components absorb the transient voltage and common mode currents coming through the drive cables. Here’s more about how inductive absorbers work: 

• Installation is completed on-site and can be done in a matter of minutes.
• Currents are absorbed before they reach the motor, so shaft contaminants aren’t an issue.
• There are no extra parts — cores are installed between the motor drive and the motor, even in harsh conditions.
• No hybrid or ceramic-coated bearings are needed.
• Inductive absorbers last for the whole life of each system. Since they’re not mechanical, they only need to be installed once.

Inductive absorbers absorb excess electricity on the power cables coming from the VFD before it gets to the motor. After the equipment is turned off, all excess energy captured by the absorbers will dissipate safely.

There are no motor modifications or shaft preparation required — it’s a very easy installation. In addition, this solution can be added to systems with very minimal downtime. 

Extend the Lifespan of Bearings With Industrial Electrical Company

Industrial Electrical Company is now stocking CoolBlue Inductive absorbers and has trained technicians available who can perform system diagnostics on site. We can furnish and complete installation for CoolBlue Absorbers. After installation, we also offer post-installation testing to report on the resulting shaft current mitigation.

If you would like to minimize recurring costs and protect bearings, consider investing in an inductive absorber like CoolBlue. Contact us today or download the CoolBlue Design Guide for VFD Applications to learn more.