Emerson 2130 RBM Consultant Pro, Справочное руководство

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Appendix
B-1
B
Foot Pre-Check Types
Foot Pre-Check Measurement Methods – Soft Foot and Frame Distortion
Index (FDI)
Soft foot is a condition where all feet (typically four) of a machine component
(such as a motor or gearbox) will not rest on the same plane. This condition also
exists if the machine baseplate pads (where the machine foot rests) are not on that
same plane. If this condition continues to exist and is not corrected, two problems
will occur.
First, it will be very difficult to align the machine. You will appear to be “going in cir-
cles” trying to move the machine into alignment. Second, but most important, the
machine will not operate properly. The component was 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 pre-
vent binding, you must check all the feet,
even those on the machine not being moved .
Traditional methods of measuring soft foot conditions included mounting a dial
indicator at the machine foot (similar to Fig 1). The hold-down bolt was then loos-
ened while the indicator was watched for movement. If the indicator moved more
than a predetermined amount (usually 0.003 inch), the foot required correction.
A shim equal to the amount of the indicator movement was then shoved under the
foot.
Fig 1
Fig 2