43
Tolerances for hydrounit assembly '
(vertical units)
Measurement Tolerance
Stator air gap
± 5% of nominal design air gap
Stator concentricity
± 5% of nominal design air gap
(Relative to turbine guide bearing)
Upper generator guide bearing concentricity
± 20% diametrical bearing clearance
(Relative to turbine and lower
generator guide bearing)
Lower generator guide bearing concentricity
± 20% diametrical bearing clearance
(Relative to turbine and upper
generator guide bearing)
Seal ring concentricity
± 10% diametrical seal ring clearance
(Relative to turbine guide bearing
and each other)
Circularity of stator
± 5% of nominal design air gap
Circularity of rotor
± 5% of nominal design air gap
Stator vertically
± 5% of nominal design air gap
(Relative to plumb)
Rotor vertically
± 5% of nominal design air gap
(Relative to generator shaft)
Static shaft runout
0.002 inch multiplied by the length of the shaft from the
(Orbit diameter)
thrust bearing to the point of runout measurement
divided by the diameter of the thrust runner. AR
measurements in inches.
divided by the diameter of the thrust runner. AR
measurements in inches.
Plumb of center of shaft runout
0.000025 multiplied by the length of the shaft from the
highest plumb reading to the lowest plumb reading.
highest plumb reading to the lowest plumb reading.
Distance from wicket gate to unit center
± 0.0002 X R
(R - figure Cl)
Distance between wicket gates (D - figure Cl)
± 0.0001 X D
Plumb of wicket gates'
20% of minimum diametxical wicket gate bushing
clearance
clearance
Parallehsm of facing plates
20% of total (top + bottom) wicket gate clearance
Levelness of facing plateS2
20% of total (top + bottom) wicket gate clearance
`
1 These tolerances are intended to be used when manufacturer's tolerances are not available. Always consult equipment manufacturer first
ff possible. This table is based on the table "Bureau of Reclamation Plumb and Ahgrunent Standards for Vertical Shaft Hydro Units," by Bill Duncan,
May 24, 1991.
May 24, 1991.
2 Plumb of wicket gate and levelness of facing plates can be outside of these tolerances as long as the facing plates do meet the criteria for
parallelism and the gates are within 20 percent of the minimum diametrical wicket gate bushing clearance of being perpendicular to the facing plates.