What Caused My Motor Shaft to Break?

One of the most expensive failure modes of electric motors is breakage on the output shaft. This is where at some point during the motor’s life cycle stress risers were introduced to the shaft material by environmental conditions, misapplication, abuse or even manufacturing defect. So how does one sort out what happened? Diagnoses of this failure mode starts with an inspection of the actual breakage. What you see at this spot will tell you a story of what caused this to occur – if you know what to look for.

The Crack Runs Parallel to the Shaft

This type of look is defined by a crack running along the length of the motor shaft and often, when the failure happens, it is described as the shaft “shattered”. The cause of this is a load pressure running through the center of the shaft. This is often found when a vertical facing motor has a load set on top with improper mounting.

The Shaft has Multiple Breaks in a Circular Pattern

When a shaft has a sort of circular pattern of breaks, seemingly to rotate in one direction, this is a sign of torsional overload. Basically, the shaft had a braking force along one spot while the rest of the shaft was free to turn. This is seen a lot on cases where a coupling of some sort of attachment was misapplied or locked down and torsional force twisted the shaft to the point of breakage.

Snapped Shaft, Somewhat Clean and Starting on One Side

The clean break shaft failure usually has an accompanied feature of also having a slight bend to the shaft as well. This is because this type of break is caused by a bending force brought on by excessive radial load. This failure is seen in applications where belts and pullies are in use and misapplied or maintenance incorrectly. Often the belt will be drawn too tightly leading to an eventual failure.

Whether you know what caused your motor shaft breakage or not, the experts at Global Electronic Services are here to help! Be sure to visit us online at gesrepair.com or call us at 1-877-249-1701 to learn more about our services. We’re proud to offer Surplus, Complete Repair and Maintenance on all types of Industrial Electronics, Servo Motors, AC and DC Motors, Hydraulics and Pneumatics. Please subscribe to our YouTube page and Like Us on Facebook! Thank you!

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