Jack Claxton, P.E., served as chairman of the HI Vibration Committee from 1995 to 2012 and has been chairman of the HI Dynamics of Pumping Machinery Committee since its inception in 2005. He has worked for Patterson Pump Company in Toccoa, Ga., since graduating from the Georgia Institute of Technology in 1975. He is vice president of Engineering and has worked as the Engineering Department head for 33 years. Patterson Pump is a Gorman-Rupp Company. Claxton may be reached at jclaxton@pattersonpumps.com. The author would like to thank Fred Buse for providing helpful comments during the development of this article.

A simple mathematical model can be used to estimate vibration at the top of the motor in a vertical pump-motor structure.