Emerson 2130 RBM Consultant Pro, Reference Manual

Page: 369 / 394

A-5 Alignment Application Notes
Pre-job Preparation and Setup
Before starting any alignment job, the history of alignments performed on this
machine(s) should be reviewed. Were any special problems found during the pre-
vious alignment; if so, what were they (soft foot, piping strain, coupling problems,
etc.)? How well was the machine aligned and who performed the alignment?
Answering these questions along with having a predefined job setup reduces the
pre-job preparation time and decreases the total time to do the job.
Now that the past is known, before proceeding with alignment measurements,
ensure that your machine(s) are mounted on the base, or foundation, with no soft
foot condition present. If one of your machines is defined to be fixed, soft foot
should be checked for that machine also. Soft foot problems can place stress on the
machine when the anchor bolts are tightened. Uneven height of the base surface,
dirt or corrosion under the feet, or other irregularities can all cause the machine to
be supported unevenly — a condition known as “soft foot”. In addition to preventing
proper machine alignment, extreme soft foot conditions can actually cause
damage to the machine (warped or cracked feet, etc.).
Two major reasons for correcting soft foot are (1) to avoid “chasing your tail”
during the alignment and (2) to remove the stress and enable the machine(s) to
operate at their best. Therefore, all machines should be checked for soft foot, not
just the machine being moved.
Additional pre-alignment considerations include:
• Proper foundation
• Grouting (suitable material with no voids or cracks)
• Baseplate (must be clean, rigid, and properly designed)
• Coupling (properly selected and installed)
• Machinery element supports (no cracks and tight)
• Minimize pipe strain
Proper Foundation
On new installations, allow foundation concrete to cure sufficiently before
installing your machines. Normally, you should not mount machines directly on
the foundation. Base plates usually provide more stability. Also, to make future
alignments easier, a set of high quality (stainless steel, etc.) pre-cut shims should be
placed beneath each foot. These should be at least 1/8 inch (3 mm) thick.