Emerson 2130 RBM Consultant Pro, Справочное руководство

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A-6 -
Coupling Considerations
Emerson’s alignment system is not affected by axial float and the effects from tor-
sional play (backlash) in the coupling are minimal. However, you should ensure
that the coupling is properly installed and not in such poor condition that it
adversely affects the alignment process. Also, Emerson recommends (while align-
ment is being performed) that you eliminate torsional play by rotating the driving
machine in the same direction that it normally operates. If necessary, put a drag on
the driven end to prevent gravity overswing.
Minimize Pipe Strain
Excessive pipe strain can create serious problems and should be corrected before
attempting machine alignment. Ensure that pipes are fitted correctly and, if neces-
sary, have some flexibility. In some cases, stationary pipes fitted directly to the
machine can cause machine movement as they heat up (thermal growth).
Changes That Occur During Operation
Machine alignment can change significantly as machines are started from a “cold”
position and run up to operating speed (“hot” position). Some factors that can
influence alignment include:
• Thermal growth
• Torque transmission forces
• Aerodynamic forces
• Hydraulic forces
Thermal Growth
Unfortunately, machines that must be aligned may not expand thermally at the
same rate. Because of this, you may have to intentionally misalign them in their
“cold” positions in order to achieve alignment when they are “hot”. The following
drawing shows an example of this.