Manual Chapter 5

5-30 Using UltraSpec Alignment - General Overview
Tolerances
The amount of offset and angular misalignment displayed is based upon the
last full set of alignment readings. All shaft misalignment is a combination
of offset and angular misalignment (see “Alignment Application Notes” on
page 8-3). This screen breaks down the misalignment into each component.
The amount of each type of misalignment is shown for both the horizontal
and vertical directions (for horizontal machines). These values are only used for
tolerances therefore, only absolute values are used (no negative signs).
Standard
The combination of offset and angle is a direct indication of the alignment
condition. Optimum alignment occurs when offset and angle are zero. In
most cases, that degree of accuracy is not practical. For that reason, toler-
ances are used to set an achievable goal. CSI’s recommended tolerances
(referenced to RPMs) are listed in the table below.
Values in the table are assumed to be pure offset or pure angle. However,
in most cases, you will have a combination of the two and tolerances should
account for this combination.
For example, for an 1800 RPM machine which has 3.5 mils of pure offset
misalignment, the alignment is in the acceptable range. Or, if it has 0.80
mils/inch of pure angular misalignment, the alignment is acceptable. How-
ever, if the remaining misalignment is a combination of 3.5 mils offset and
0.80 mils/inch angular, the misalignment is not as good, and should be con-
sidered out-of-tolerance.
Speed
(RPM)
Excellent Acceptable
Offset
(mils)
Angle
(mils/inch)
Offset
(mils)
Angle
(mils/inch)
< 500 5.0 1.5 6.0 2.0
500 - 1250 4.0 1.0 5.0 1.5
1250 - 2000 3.0 0.5 4.0 1.0
2000 - 3500 2.0 0.3 3.0 0.5
3500 - 7000 1.0 0.25 2.0 0.3
> 7000 .5 0.2 1.0 0.25