Machinery's Handbook, 31st Edition
SHAFT ALIGNMENT
2745
14th Arrangement.— Place rim and face indicators as shown in Fig. 14a.
A
A f B A f C
2 2 ! ! # ! ! #
F r R r
r
= − + − = − + −
f
F
R
B
C
Fig. 14a. Dial Indicator Arrangement 14
_
+ +
O
+
+
+ O
_
O
O
O
_
+ _
_
O
_
Fig. 14b. Interpreting Dial Indicator Readings for Indicator Arrangement 14 Solid lines represent the desired location for the dashed lines (movable unit). The plus, minus, and zero readings on the indicators are represented by one of these nine scenarios. Depending on the magnitude of the variables, the generic graph gives a mental picture of what the formulas should yield. Example: Calculate the shims necessary for a pump and motor alignment where dimen sions are A = 4.625 inches, B =10.75 inches, and C = 32.5 inches. The two indicator dials read r = minus ( − ) 0.014 inch and f = plus (+) 0.036 inch respectively. Solution: In Fig. 14b, the negative rim and positive face condition is shown in the top left block. The graph suggests that both the front and rear motor feet should be lowered, depending on the magnitude of the variables. The formula solution dictates exactly how much the movable unit is to be lowered at both front and rear shim points:
A f B
A f C
! ! #
! ! #
F r
R r
. 2 0014 2 = − + − = − − = + − =− ^
. 2 0014 2 = − + − = − − = + − =− ^
. 4625 0036 1075 . . #
. 4625 0036 325 . . #
+ −
+ −
. 0007 00837 0077 . . inch
. 0 007 0 25297 0246 . . inch
h
h
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