User Manual

A-2 Foot Pre-Check Types
This method assumed that a parallel soft foot existed. However, a large per-
centage of problem feet are
angular soft feet (similar to Fig 2). Correcting this
type of problem with a full shim can make the condition worse
(see Fig 3). Correction should be determined with a set of thickness gauges
(feeler gauges). The result is usually a wedge shim similar to Fig 4.
The laser alignment system allows you to locate the problem feet and
bypass those feet that are OK. While the hold-down bolts are individually
loosened and retightened, the laser system will measure the shaft to shaft
position. This actually measures how much each connection affects shaft
alignment. In a perfect condition, loosening bolts should not move the
shafts at all.
Two different laser methods are available to evaluate the measured move-
ment at the shafts. They are:
• Soft Foot
• Frame Distortion Index (FDI)
Although they evaluate the data differently, both methods give you a sense
of soft foot severity at each location. Soft Foot results are shown by the
number of X’s displayed and FDI results are shown as a numerical value.
Fig 3
Fig 4