As a follow-up on our previous post about electric-motor maintenance tips, we found a prime example of over-lubrication from one of the repair jobs in our motor shop.
We unloaded the motor - it seems fine to the untrained eye.
We've got it on our work-space and it still doesn't look all that bad...
When we open the casing, we see the cause of failure.
If you had your doubts about over-lubrication, hopefully these photos will be a stern warning. Over-lubrication can cause a motor to overheat and short the windings in the motor. Fortunately in this instance, our customer didn't have to pay for a full rewinding or a replacement motor. Our boys in the shop were able to clean the excess grease out of this motor and get it back in service without any problems.