Guest Post: Fred McWilliams, Lovejoy Canada
Early one dark rainy morning in early 2010, I received
an irate phone call from the head of production at one of the steel mills I support. He wanted to know why our disc coupling had come off a 250hp
motor shaft in a catastrophic failure
at 4.00 am that morning.
While, fortunately, no one was injured in the failure, his production has stopped and he wanted me to visit his
plant immediately. He was too “hot up”, for me to get any further information.
I told him I would come right away.
While driving to the plant, I received a call from a fluid coupling manufacturer's representative, who told me that he had also been summoned, as
his fluid coupling had also been part of the failure.
As Lovejoy Canada supplies this steel mill with SX255-6 Disc coupling assemblies (consisting of 3 hubs and 2 disc packs), that bolt either side of a fluid coupling at this facility, I now could understand why the fluid coupling representative was also involved in this issue.
Upon arriving at the job site, both the fluid coupling manufacturer's representative and I were
astonished to see the condition of the 250 hp 449T frame 3 ¾” diameter
shaft. It was bent almost at a right angle and there was severe heating
scars on it.
Upon talking to the maintenance crew, we found out that this
particular motor had been making “grinding noises”, for some time and nothing
had been done to find out why this was occurring, due to being unable to have
Both the fluid coupling representative and I suggested that the motor be thoroughly
examined to see if there was a reason for the bent shaft. It was obvious to us
that there had been a failure within the motor that must have caused excessive
overheating to the point that the motor shaft had deformed and stopped suddenly, causing the fluid coupling assembly to come off the shaft and break
through the coupling guard.
Lovejoy Canada, the fluid coupling manufacturer, and the motor supplier
were asked to replace the damaged parts ASAP so that production could be
re-started as quickly as possible.
Lovejoy Canada had our coupling components on our shelf in our
Mississauga Ontario warehouse and they were shipped to the customer that
Within a couple of days the drive assembly was completed and
A report on the motor found that a rear bearing had seized,
causing excessive overheating and deformation of the motor shaft. The new assembly
has now been running successfully for over four years, and is “Red Flagged” for
regular maintenance. A crucial maintenance/production lesson has also been learned.
While I never did get an apology from the Head of Production for his irate phone call, I did derived a great deal of satisfaction from being able to help him quickly troubleshoot the failure and get his production again.
So to directly answer the subject question, “Can a good coupling protect against ignored maintenance?" The answer is obviously and unfortunately "No". While no equipment will last very long if it is neglected and abused, using high quality products within their designed working envelope (like the Lovejoy SX255-6 disc coupling) will help keep
equipment running for a considerable length of time. Again, using quality products should never be an excuse to ignore regular system maintenance.
About the Author: Fred McWilliams has served as Lovejoy Canada's Eastern Accounts Manager for well over a decade. To tap into Fred's rich industry knowledge and experience, please contact him through Lovejoy Canada or reach out to him directly on LinkedIn.