Before Decatur Industrial got involved, this large grain processing company had suffered two bearing failures in less than two years. They called us in to fix their 450HP motor, which was driving a large fan in their feedhouse, and they told us the story of their repeat catastrophic failures. They wanted to know why it kept happening!
Diagnosing the problem: When we arrived on scene the motor was still in place running and our reliability specialist could hear bearing fluting as the motor had an audible howl to it. With our SKF Arc meter and vibration analysis we verified the existence of electric current at both motor bearings and also at both driven fan bearings. Once the motor was able to be brought to our service center, we verified the bearings were indeed suffering from classic bearing fluting. Current discharge from voltage passing through the bearings as long been associated with large electric motors; however, the increased use of variable frequency drives (VFDs) has since resulted in shaft voltages in small low voltage machines.
The fix: We insulated the ODE bearing housing and installed an AEGIS grounding ring – this motor has now been in place and running for four years with no subsequent bearing failures. It operates noise free and vibration readings show no bearing issues. The customer has saved approximately $80,000 in repair costs over what they had been spending in repairs – plus no more downtime due to motor issues.