Protect your ball bearings: 8 common problems

Identifying the primary reason for premature motor failure is as easy as looking at the bearings.

By David Manney July 27, 2016

One of the more common issues that can occur in any industrial facility is the possibility for premature motor failure. It is not only a costly problem due to the repairs that may be necessary, but the unexpected downtime can bring your operation to a halt until the repairs take place. Identifying the primary reason premature motor failure occurs is as easy as looking at the bearings.

Some issues could happen and result in damage to the motor or catastrophic failure. Identifying the problem, including the source of the issue, is half of the battle. It is then important to protect the bearings from further damage, resulting in longer equipment life and fewer maintenance issues along the way. Here are some common problems:

  • Misalignment: The raceway ball track must be parallel to the raceway edges. If it isn’t, bearing damage and the possibility of equipment failure could occur.
  • Lubricant: If the lubricant fails, it typically results in blue or brown discolored ball tracks and balls.
  • Contamination: This issue could lead to indenting of the raceway or the balls themselves.
  • Overheating: If overheating is a problem, it may lead to a discoloration of the balls, rings, and cages.
  • Load: When excessive load is a problem, it may result in fragmentation in the ball path.
  • Tight fitting: If the bearings fit too tightly, it could lead to ball wear seen in the bottom of the raceway.
  • Loose fitting: If the bearings fit too loosely, it could result in a discoloration of mounting surfaces or circumferential wear.
  • Bearing current: When current flows through the motor bearings, it could lead to fluting.

Methods for protecting the bearings

If you see any issues in the bearings, the root cause needs to be identified and corrected. This helps to reduce any problems that could occur in the future. It is also important to protect the bearings, and this can be done in some of the following ways.

  • Shaft grounding brush: This prevents fluting damage by diverting shaft voltages to ground, rather than having it run through the bearings. A grounding brush helps prevent damage associated with shift current and can extend the life of the motor considerably.
  • Bearing isolator: This is a two-part seal that consists of a stator (press fitted to the housing) and a rotor (attached directly to the shaft). Since the rotor is connected to the shaft, it revolves along with it. This creates a noncontacting seal and eliminates wearing, helping to protect the bearings and keep them free of contamination and properly lubricated.

Ensuring that the bearings are not experiencing any problems can be part of a preventative maintenance program. They can be checked daily using an IR scanner or stethoscope. The surface temperature of the bearings can also be checked with a thermometer or through electronic sensing devices. Stick-on labels are also available for that purpose.

As part of the maintenance program, the installation of bearing protection rings and isolators can play a vital role in keeping your facility up and running by avoiding equipment failure.

David Manney is a marketing administrator at L&S Electric. This article originally appeared on L&S Electric Watts New Blog. L&S Electric Inc. is a CFE Media content partner.

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