Why are machines accurately aligned with each other? 23:1 ✔️Ans -
Machines are accurately aligned to work together smoothly. Thus
increasing working life.
How is the Primary unit positioned? 23:1 ✔️Ans -The primary unit is
positioned according to reference lines (centre-lines, benchmarks etc)
What are the other machines aligned with the Primary unit? 23:1 ✔️Ans -
Drive units; prime movers, transmission units etc. Are usually aligned with
the primary unit.
How is an alignment procedure chosen? 23:2 ✔️Ans -The alignment
procedure used is determined by the type of components connecting the
units.
What procedure is used to align coaxial shafts? 23:2 ✔️Ans -In-line
(coaxial shafts) are usually alogned with couplings in a procedure called
coupling alignment.
What are the results of coaxial misalignment? 23:2 ✔️Ans -Results of
coaxial misalignment are:
-reduced bearing life
-coupling damage
-high vibration
-reduced seal life
-increased downtime and costs
What conditions of misalignment are present in misaligned coaxial shafts?
23:2 ✔️Ans --offset
-angular
To align shafts correctly, in what two planes must these conditions be
solved? 23:2 ✔️Ans -Shafts must be align in both horizontal & vertical
planes
, Why is vertical alignment corrected first? 23:3 ✔️Ans -Because it is very
easy to disturb horizontal alignment when correcting the vertical
alignment.
How is vertical misalignment corrected? 23:3 ✔️Ans -By using shims
underneath the machine feet
How is horizontal alignment corrected? 23:3 ✔️Ans -By adjusting the
position of the unit on its base with jacking screws
Define angular misalignment. 23:3 ✔️Ans -Angular misalignment occurs
when the coupling faces are not parallel with each otheras well as the shaft
centre-lines.
How is angular misalignment corrected horizontally & vertically? 23:3
✔️Ans -Horizontal: jacking screws
Vertical: correct amount of shims under front and back shims.
Define offset misalignment. 23:3 ✔️Ans -When the centre-lines of both
shafts are parallel but not in-line.
How is offset misalignment corrected horizontally? 23:3 ✔️Ans -By
moving jacking screws on one side evenly till shafts are in-line.
How is offset misalignment corrected vertically? 23:3 ✔️Ans -By adding
or removing an equal amount of shims from all feet to bring shafts in-line.
Describe combination misalignment. 23:4 ✔️Ans -Combination
misalignment occurs when both angular & offset misalignment are present
between coaxial shafts.
Define Softfoot. 23:4 ✔️Ans -Softfoot occurs when a machines feet do not
equally support its weight; it does not sit firmly on all feet.
How does softfoot effect the machine? 23:4 ✔️Ans -Softfoot will stress the
machine housing and ovalize bearing bores.
What causes Softfoot?
23:4 ✔️Ans -Softfoot can be caused by:
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