Machinery's Handbook, 31st Edition
2740 SHAFT ALIGNMENT 9th Arrangement.— Place rim and face indicators as shown in Fig. 9a. The driven unit here could be any of several devices including the “catch” drum for a centrifugal clutch.
f
r
A
A f B A f C
2 2 ! ! # ! ! #
F r R r
= − + = − +
F
R
B
C Fig. 9a. Dial Indicator Arrangement 9
- -
-
+ -
o
o
o
o
-
o
+
+
+
+
-
o
+
Fig. 9b. Interpreting Dial Indicator Readings for Indicator Arrangement 9 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 =10.375 inches, B = 22.0 inches, and C = 48.0 inches. The two indicator dials read r = 0.00 inch and f = plus (+) 0.017 inch respectively. Solution: In Fig. 9b, the center block of the bottom row represents zero rim and positive face values. The graph suggests both the front and rear motor feet be moved up by adding shims, depending on the magnitude of the variables. The formula solution below dictates that the front feet be moved up 0.036 inch and the rear feet be moved up 0.079 inch:
A f B
A f C
! ! #
! ! #
F r
R r
. 2 000 = − + = − + =− + = . 0036 2
. 2 000 = − + = − + =− + = . 0079 2
. 10375 0017 22 . #
. 10375 0017 48 . #
. 000 0036 .
. 000 0079 .
inch
inch
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