Machinery's Handbook, 31st Edition
SHAFT ALIGNMENT 2741 10th Arrangement.— Fig. 10a illustrates an arrangement used for taking two separate readings with one dial indicator.
r
f
A
A f B A f C
2 2 ! ! # ! ! #
F r R r
= − + − = − + −
F
R
B
C Fig. 10a. Dial Indicator Arrangement 10
RIM: MINUS FACE: PLUS
RIM: ZERO FACE: PLUS
RIM: PLUS FACE: PLUS
RIM: MINUS FACE: ZERO
RIM: ZERO FACE: ZERO
RIM: PLUS FACE: ZERO
RIM: MINUS FACE: MINUS
RIM: ZERO FACE: MINUS
RIM: PLUS FACE: MINUS
Fig. 10b. Interpreting Dial Indicator Readings for Indicator Arrangement 10 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 = 5.50 inches, B =14.0 inches, and C = 35.0 inches. The indicator readings are r = plus (+) 0.030 inch and f = plus (+) 0.022 inch, respectively. Solution: In Fig. 10b locate the block illustrating the positive rim and positive face con dition. The graph suggests both the front and rear motor feet be lowered. The formula solution dictates exactly how much the movable unit is to be lowered at both front and rear shim points:
. 2 0030 = − + − = − + − =− + − =− . A f B 2 inch ! ! # ^
. 2 0030 = − + − = − + − =− + − =− . A f C 2 inch ! ! # ^
F r
R r
. 55 0022 14 #
. 55 0022 35 #
. . 0015 0056 0071 .
. . 0015 0140 0155 .
h
h
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