Machinery's Handbook, 31st Edition
2746 SHAFT ALIGNMENT 15th Arrangement.— Place rim and face indicators as shown in Fig. 15a.
r
A
A f B A f C
f
2 2 ! ! # ! ! #
F r R r
= + − = + −
R
F
B
C Fig. 15a. Dial Indicator Arrangement 15
RIM: ZERO FACE: PLUS
RIM: MINUS FACE: PLUS
RIM: PLUS FACE: PLUS
RIM: MINUS FACE: ZERO
RIM: ZERO FACE: ZERO
RIM: PLUS FACE: ZERO
RIM: PLUS FACE: MINUS RIM: MINUS FACE: MINUS Fig. 15b. Interpreting Dial Indicator Readings for Indicator Arrangement 15 RIM: ZERO FACE: MINUS
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 = 6.0 inches, B = 38.0 inches, and C = 84.0 inches. The two indicator dials reads r = minus ( − ) 0.002 inch and f = plus (+) 0.003 inch respectively. Solution: The negative rim and positive face condition is found in the top right corner of Fig. 15b. The graph suggests that both the front and rear motor feet need to be lowered. 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
. 2 0002 2 = + − = − inch =− + − =− ! ! #
. 2 0002 2 = + − = − inch =− + − =− ! ! #
F r
R r
. 60 0003 380 . . #
. 60 0003 840 . . #
+ −
+ −
. . 0001 0019 0020 . ^
. . 0001 0042 0043 . ^
h
h
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