If these values are known, the installation of the equipment can be aligned to account for this movement and the risk of failure from excessive overhung load can be reduced. A good indication that a drive is experiencing excessive overhung load is when equipment that has been running successfully for a long time suddenly has repeated shaft or bearing failures. Installing a new motor, shaft or bearing without proper alignment leads to excessive misalignment overhung loads. When to Expect Failure From Excessive Overhung Loads Repeated failures of coupling elements, either rubber or steel, can be from overhung loads resulting from severe misalignment. This overhung load can lead to more catastrophic shaft or bearing failures.
Overhung load causes high stress at a point such as a keyway, notch or fretted surface.
Contact seals can experience immediate leaking if overhung loads cause the shaft to put pressure on one side of the seal. The lack of contact 180 angular degrees away can cause a gap between the shaft and seal. Gear teeth that show a carrot-shaped wear and pitting across the face width, can be a result of external loading or overhung load misalignment. Remember that all rotating equipment experiences some overhung load. The key is to keep the load within the specific design limits of the equipment.