As part of a seismic analysis for a 1000 horsepower vertical 14 pole induction pump motor the reed frequency was calculated using a finite element analysis (FEA) program. This paper will discuss the FEA modeling for the seismic analysis and natural frequency determination. The calculations were done for the
motor only on a rigid support. After the motor completed the standard factory tests, an impact test was conducted in the rigid mount condition to determine the structural natural frequencies. The tested values will be compared to the calculated values from the FEA model. This paper will also discuss the subsequent motor/pump system resonance problems that surfaced after the motor/pump was installed on site. This paper will highlight the importance of the system integrators design of the motor support structure to avoid structural resonance problems such as in this case.

I want to devote this article to the practical application of modal analysis. I have never dealt with modal analysis, there were no devices with corresponding functions, and now they are not and are not expected. Very expensive. But this is not a reason to despair and put an end to such an interesting method. The solution to the problem is 3D modeling and calculation of vibration modes. How I came to this, how to do it and what I got in the end - read on.