Good Day!
I am an electrical engineer working as a Lead Electrical Inspector in an iron ore processing company (sinter plant) in the Philippines. We have more or less 25 units of 110/220/300KW of squirrel cage induction motors used to drive conveyor lines. Recently, we have arrested around 10 cases of rotor bar problems through vibration analysis. At first, i have no idea on the vibration profile of such problem. Discovery of the problem and the development of the technique started when one of our 300KW motor exploded because of cut-off rotor bars. Now i have many data including photos of those cases. When i started to recommend motor pull-out and find positive results, i made a post (something like this) at SKF CM Forums last January 2006 and many replied to me.. but i wasn't able to give them data right away since at that time, motor overhauling, one after the other was ongoing. I just told them to wait and give me time. But now, i have more data. If anyone of you is interested to know about these problems i have encountered, send me an email at meilanreyamper@yahoo.com
i can give you data and share my experience to help you prevent catastrophic failures in your motor. It can also be added in your materials for those who are conducting trainings or lectures.

This message has been edited. Last edited by: Rotoras,

I would be very interested to hear more and I'm sure others would as well.

Can you post the info here? Note you can add attachments (one attachment per message) by clicking the "Add Attachment" link at the lower left corner of the edit-message screen.

I'm definitely interested in hearing more about your issues, especially what kind of vibration levels your motors were experiencing.

Steve

Would love to hear more about this! Sounds very interesting.

Dear All,

Thanks for your interest.
Please let me know your email address so i can send you documents.

Sincerely,
Meilan Rey T. Amper

MRTamper,

Online motor circuit testers made by Baker, Framatome ANP, and PdMA all do an excellent job of finding rotor bar problems and flagging them automatically. I have an example of a rotor bar problem found in a facility by me using the PdMAEmax that is posted on the main page of ReliabilityWeb.com, under the "motor" section and you need to scroll way, way, way down to get to it.

Since then I have found numerous rotor problems with this technology and its usually right on the money with few false positives. Just recently a comparison test was done on a rotor with vibration analysis and the Baker Explorer with very similar results as both confirmed a very low level rotor bar problem, probably just porosity because its not changing in amplitude.

Hope this helps!


Jim

Thank you very much for sharing your experience. That gives me another option now that i am trying to have an MCSA capability here in our plant. We have so many electric motors, more or less 900 ranging from smallest and up to 6.5MW motor. We should have those motor circuit testing devices, not just vibration analyzers.

Once again thank you!

MRTA