J. Stanton McGroarty, CMfgE, CMRP, is senior technical editor of Plant Services. He was formerly consulting manager for Strategic Asset Management International (SAMI), where he focused on project management and training for manufacturing, maintenance and reliability engineering. He has more than 30 years of manufacturing and maintenance experience in the automotive, defense, consumer products and process manufacturing industries. He holds a bachelor of science degree in mechanical engineering from the Detroit Institute of Technology and a master’s degree in management from Central Michigan University. He can be reached at
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Daniel’s Dayton drives the Ludlow through a flat belt from a home-made motor mount, so alignment is most likely imprecise. Lubrication has been whatever was provided to a fan in a Houston print shop since 1949, followed by whatever is provided to a replacement motor sitting just above the floor in the same environment.
We can safely characterize the reliability strategy for the motor as “run to failure.” Vibration analysis, thermography, tribology, ultrasound testing and any other PdM have not been part of the maintenance program supporting Daniel’s Dayton. The term “precision maintenance” did not occur in the article about the oldest motor.
In the preparation of this report, I reviewed the case of the oldest motor with a couple of independent engineers. Our total experience exceeds 100 years and an immense quantity of lager. The conclusion of this august body is that some equipment runs forever just to annoy us. This finding may even support a new corollary to Murphy’s Law, stating that some equipment will refuse to wear out just to discredit the rules of reliability.
The panel also achieved consensus around the notion that, if you’re looking for equipment that is just too ornery to die, Houston is probably a good place to start. Better yet, make it summer in Houston. That’ll weed out the weak ones.
Read Stanton McGroarty's monthly column, Strategic Maintenance.
Comments
The reliability of this motor actually does not surprise me at all, not even considering that is took the place of a motor 2.5 times its rating. Blame it on period technology. Efficiency and precision have improved over the decades since this motor was manufactured, but nothing beats the design fudge factors used in the slide rule days to improve longevity. It was not uncomon for a motor to be capable of twice its rated load without overheating. Bearings were much beefier too. It was also considered good practice to specify a larger motor than needed to power a particular piece of equipment. I have often requested that motors of 60s vintage and older be rebuild instead of replaced simply because they will withstand a lot more abuse and inattention than their modern counterparts. This is not to say that I don't believe in progress. Todays motors are more efficient, smother running, lighter weight, and less expensive to manufacture. However when the cost of a new motor is higher than the combined cost of a rewind and the net present value of the energy savings, why throw it out?
Thomas Jones
