Optimal foundation design of a vertical pump assembly

Generally, a vertical pump assembly consists of a pump, a driving motor on top and a foundation structure at the bottom to support the pump and motor assembly. They together constitute a system, which has its own dynamic characteristics. The prominent excitation to the assembly comes from the rotating speed and its related harmonics during pump operation. This calls for careful design of the pump support to keep the system natural frequencies well separated from the pump speed (as well as motor speed in case of a geared system) and its multiples for trouble-free operation. Since there is little scope for structural modification of the pump and motor unit, it is better to design the foundation structure adequately before installation of the pump to meet the desired objective. Such an attempt has been made for the design of a foundation structure using finite element (FE) analysis for a typical vertical pump to be installed in a research facility in BARC, Mumbai.