Machinery's Handbook, 31st Edition
2742 SHAFT ALIGNMENT 11th Arrangement.— Place rim and face indicators as shown in Fig. 11a.
A
A f B A f C
2 2 ! ! # ! ! #
F r R r
= + − = + −
r
f
F
R
B
C
Fig. 11a. Dial Indicator Arrangement 11
-
o
+
+
+
+
-
o
+
o
o
o
-
- o
+
-
-
Fig. 11b. Interpreting Dial Indicator Readings for Indicator Arrangement 11 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 necessary shims for a pump and motor alignment where dimen sions are A = 6.50 inches, B = 16.625 inches, and C = 42.0 inches. The two indicator dials read r = 0.000 inch and f = minus ( − ) 0.026 inch respectively. Solution: The center block in the last row of Fig. 11b describes the zero rim and negative face value condition. The motor is too low because of angularity (face reading), but the elevation is correct at the axial position of the rim indicator reading. The graph suggests both the front and rear motor feet be moved up. The formula solution dictates exactly how much the movable unit is raised at both front and rear shim points:
. 2 = + − = + − − = + = . . . 000 00665 00665 . A f B 2 000 inch ! ! #
. 2 = + − = + − − = + = . . . 000 0168 0168 . 2 000 inch ! ! # A f C
F r
R r
. 650 0026 16625 . #
. 650 0026 42 #
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