Page 121 - Rotating Machinery Pratical Solutions to Unbalance and Misalignment

Advanced Machine Alignment
Chapter
Chapter
Chapter
Chapter
Chapter
Advanced
Advanced
Advanced
Advanced
Advanced
Machine Alignment
Machine Alignment
Machine Alignment
Machine Alignment
Machine Alignment

INTRODUCTION

recision alignment of equipment shafts to one another is
critical in extending the useful life of various machine com-
P P P P P ponents, and in preventing catastrophic failures. The two
most common sources of machine vibration are misalignment and
unbalance. Often these two sources will account for over 90% of
all machine problems occurring in any given plant.
During the alignment process, many sources of machine un-
balance can be detected and corrected. Thus, a complete under-
standing of precision alignment and an understanding of the
sources of machine unbalance are critical skills to the plant repair-
man. The topic of unbalance has been covered, but will be dis-
cussed during the alignment presentations.
The first method of alignment that will be presented is an
advanced version of the commonly known Rim and Face method.
Both graphical and analytical solutions to the alignment process
will be presented. Thermal growth and other machine consider-
ations will be discussed in detail. In the following chapter, the
reverse indicator method of precision alignment will be discussed
in detail.
Often equipment manufacturers provide tolerances for align-
ment of their equipment. Usually this is in the form of +/- so
many mils parallel offset and +/- so many mils angularity. The
very word tolerance indicates a willingness to accept or tolerate
some misalignment. In this text, methods will be detailed to at-
tempt to align equipment to exactly zero tolerance.