Manual for Induction Motors and Generators
34 -
Installation and Alignment
3BFP 000 050 R0101 REV E
4.
Measure and note readings for parallel, angular and axial misalignment in four different
positions: top, bottom, right and left, i.e. every 90°, while both shafts are turned
simultaneously. The readings are recorded
5.
Align the machine vertically by turning the jacking screws or by jacking with hydraulic
jacks. To facilitate the alignment in the vertical plane, jacking screws are fitted to the feet
of the horizontal machine, see
Figure 3-3 Vertical positioning of machine foot
. The
alignment accuracy of the machine is sometimes affected by the thermal expansion of its
frame, see
Chapter 3.6.4 Correction for thermal expansion
6.
Measure the distance between the bottom of the machine feet and the bedplate and make
corresponding solid blocks or wedges or reserve necessary amount of shims
7.
Fit the solid blocks or shims under the machine feet. Slacken the jacking screws and
tighten the fixing bolts
8.
Check the alignment again. Make corrections if necessary
9.
Draw up a record for future checks
10. Re-tighten nuts and lock the nuts by tack welds or hitting sufficiently hard with a center
punch
11.
Dowel the feet of the machine for easy future re-installation of the machine, see
3.4.7.1 Dowelling of the machine feet.
3.6.5.5 Permissible misalignment
Definite alignment tolerances are impossible to state as too many factors have an influence. Too
large tolerances will cause vibration and may possibly lead to bearing or other damages.
Therefore, it is recommended to aim at as narrow tolerances as possible. Maximum permissible
misalignments are shown in
Table 3-1 Recommended permissible misalignments
For definitions
of misalignment, see
Figure 3-8 Definition of misalignment.
NOTE: Tolerances given by the coupling manufacturers indicate tolerances for the coupling,
not for the driving-driven machine alignment. The tolerances given by the coupling
manufacturer should be used as a guideline for the alignment only if they are narrower
than the maximum permissible misalignments shown in
