Making vertical turbine pump shaft adjustments
It is common for vertical turbine pumps (VTP) to be designed with multiple mixed flow impellers (sometimes 12 or more) and for the pump rotor to be supported by the vertical pump motor. Vertical pump motors can be solid shaft or hollow shaft. Solid shaft motors have an annular keyway in the shaft that is engaged by a solid coupling that supports the pump rotor.
Hollow shaft motors support and drive the pump rotor from the top by means of a head shaft fitted through the hollow motor shaft to the pump line shaft. In either case, there is an adjustment that lifts the pump rotor so it is supported by the motor shaft. This adjustment is obviously critical to the proper operation of the pump and motor and can have a significant effect on the motor load (current). Presented here are some of the main concerns for setting this pump lift adjustment.