1
Upper Guide Bearing
Rotor
Stator
Lower Guide
Bearing
Figure 1.--Typical hydroelectric unit.
VERTICAL SHAFT HYDROUNIT ALIGNMENT
1. INTRODUCTION
The proper alignment of a vertical shaft hydrounit is critical to trouble free operation. A
misaligned unit cannot only cause the premature failure of bearings, but through excessive
vibration, cause wear and stress on other machine components as well. Unscheduled outages
caused by misalignment can, in most cases, be avoided if the machinery is aligned correctly
initially. The purpose of this document is to provide the reader with enough information to align
a vertical shaft hydrounit within acceptable limits.
misaligned unit cannot only cause the premature failure of bearings, but through excessive
vibration, cause wear and stress on other machine components as well. Unscheduled outages
caused by misalignment can, in most cases, be avoided if the machinery is aligned correctly
initially. The purpose of this document is to provide the reader with enough information to align
a vertical shaft hydrounit within acceptable limits.
2. VERTICAL SHAFT HYDROUNITS DESCRIPTION
To better understand the alignment process, it is important to understand the basic construction
of vertical shaft hydrounits. Figure 1 shows a typical vertical shaft hydroelectric unit as found in
Bureau of Reclamation powerplants. There is a thrust bearing located above the generator rotor,
upper and lower generator guide bearings, and a turbine guide bearing. The rotating weight of
the unit is transferred through the thrust bearing, through the upper bridge, and through the stator
frame to the foundation. The lower bridge supports the lower generator guide bearing and must
of vertical shaft hydrounits. Figure 1 shows a typical vertical shaft hydroelectric unit as found in
Bureau of Reclamation powerplants. There is a thrust bearing located above the generator rotor,
upper and lower generator guide bearings, and a turbine guide bearing. The rotating weight of
the unit is transferred through the thrust bearing, through the upper bridge, and through the stator
frame to the foundation. The lower bridge supports the lower generator guide bearing and must