Emergency Situation
Case 3
An outside mechanical company came to us with a 400 Horsepower 1100 RPM electric motor that had spun a bearing. Apparently, they had already approached several other companies with their dilemma before contacting us, but no one would accept the job. We didn’t see what the big deal was until we went to the site and found the electric motor down three flights of stairs, enclosed around a maze of air doors. It must have been installed during building construction over thirty years ago!
We did a site inspection and discovered electric motor front bearing and end bell extreme high temperate marking and metal shavings. Our main concern was the 12-sheave pulley that was installed. It appeared as if someone had already tried to remove it recently.
We quickly realized that removing the motor from its location was not an option; we needed a tear down for better diagnostics to assess if the windings were damaged. We preformed a hi pot / surge test to evaluate winding conditions; they checked out, but the front-end frame and bearing was completely destroyed. The end frame and bearing had to be removed and sent back to our shop where we found the OEM of the bearing and machined end bell. We had to press fit the bearing and reinstall it. Upon testing, we took vibration and lubricant analysis and are currently performing preventative maintenance on this unit. The new unit has been in operation since May 2006.
