Emerson CSI 2140

Foot pre-check results and meaningsTable 7-1:
Soft foot
Result Meaning
OK Soft foot measurement is within the specified
tolerance.
X Soft foot measurement is 1 to 2 times the specified
tolerance.
XX Soft foot measurement is 2 to 3 times the specified
tolerance.
XXX Soft foot measurement is greater than 3 times the
specified tolerance.
Frame Distortion Index (FDI)*
Result Meaning
No box around a number Measurement condition is excellent.
Clear box around a number Measurement condition is acceptable.
Dark box around a number Measurement condition is out of tolerance.
*The higher the FDI number, the greater the severity.
CAUTION!
FDI numbers are not the required shim corrections for a foot. Soft foot and FDI
corrections require installation of wedge-shape shims. Thickness and shape of the shims
should be determined by a feeler gauge.
Foot pre-check
Soft foot is a condition where all feet (typically four) of a machine component (such as a
motor or gearbox) do not rest on the same plane. This condition also exists if the machine
baseplate pads (where the machine foot rests) are not on the same plane. If this condition
continues to exist and is not corrected, two problems will occur:
• It will be very difficult to align the machine.
• The machine will not operate properly. The component is not designed to operate in
a bound condition. When this happens, binding will occur causing stress at the
bearings and changing the operating clearances (inside the component). To prevent
binding, you must check for soft foot problems on all feet, even those on the
machine not being moved.
Traditional methods of measuring soft foot conditions include mounting a dial indicator at
the machine foot (see Figure 7-28, figure on the left). This involves loosening the hold-
down bolt while watching the indicator for movement. If the indicator moves more than a
predetermined amount (usually 0.003 inch), the foot requires correction. A shim equal to
the amount of the indicator movement is then placed under the foot. This method
assumes that a parallel soft foot existed. However, a large percentage of problem feet are
angular soft feet (see Figure 7-28, figure on the right).
Advanced Laser Alignment
214 MHM-97432 Rev 7