Nidec LSA 52.3 - Alignment of a Double-Flanged Bearing Machine; Machines Without Axial Play (Standard)

Electric Power Generation
Installation and maintenance
5382 en - 2022.11 / h
LSA 52.3 / LSA 53.2 / LSA 54.2
Industrial Range Alternators
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12
Implementation:
During the measurements, both shafts must turn
simultaneously in the same direction. (For example: the
coupling installed with its screws loosened). By turning
both shafts simultaneously, the measurement is not
affected by the error resulting from run out of the two shaft
ends.
C1
C2
A
B
3h
9h
12h
6h
L
The "C1" and "C2" micrometers are located at an angular
difference of 180°.
The longer the distance "L" the higher the sensitivity for
detecting angular errors.
The reading should be performed 4 times for the "C1" and
"C2" micrometers: at 12h, 3h, 6h, 9h.
It is recommended to record the results and draw the axes
for better evaluation, as explained below. Interpretation of
measurements by means of an example.
Values given in millimetres. The reading is considered
positive (+) when the micrometer stylus is pushed inwards.
MEASUREMENTS
C1
C2
A
B
3h
9h
12h
6h
+ 0.90
+ 1,04
+ 1.34
+ 1.00
+ 0.86
+ 1.64
+ 1.02
+ 0
.70
L=400
Measurements referring to the vertical plane:
Considering the vertical plane "C1": The vertical action
towards the top of shaft "A" on the micrometer is dominant.
In the plane "C1" the axis "A" is higher than axis "B”
(0.9 – 1) / 2 = - 0.05 mm
In the vertical plane "C2", the vertical action towards the
top of shaft "B" on the micrometer is greater.
In the plane "C2" the axis "B" is higher than axis "A"
(1.34 – 1.02) / 2 = 0.16 mm
The respective position of the axes is as follows:
A
B
C1
C2
0.05
0.16
Regarding the vertical plane, the angular alignment error is:
(0.16 + 0.05) *100 / 400 = 0.0525 mm/100mm (not
acceptable).
Measurements referring to the horizontal axis:
In the plane "C1" the axis "B" is further to the right than "A”
(1.04 – 0.86) / 2 = 0.09 mm
In the plane "C2" the axis "B" is further to the left than "A”
(0.70 – 1.64) / 2 = - 0.47 mm
The representation of the shafts is as follows:
A
B
C1
C2
0.09
0.47
Regarding the horizontal plane the angular error is:
(0.47 + 0.09) *100/ 400 = 0.14 mm/100mm
(not acceptable)
In the both planes the parallelism error is:
mm103.095
22
=+
or
mm496.04716
22
=+
(not
acceptable)
3.3.2 Alignment of a double-flanged bearing machine
3.3.2.1 Machines without axial play (standard)
Alignment must take into account, coupling tolerances.
CAUTION:
A MISALIGNMENT EVEN IF ACCEPTABLE BY THE
COUPLING MUST NOT CREATE UNACCEPTABLE
STRESS LEVELS FOR THE BEARING.
Shafts alignment limits to comply with:
0.05 mm
100 mm
0.08 mm
Parallel Error
Angular error
To check the alignment, there are different methods: the
"double concentricity" method is described in the
"alignment procedure" chapter 3.3.1.6.