Electric Power Generation
Installation and maintenance
LSA 52.3 / LSA 53.2 / LSA 54.2
Industrial Range Alternators
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3.2 INSTALLATION OF THE MACHINE
3.2.1 Coupling Assembly (double-bearing
machine only)
The coupling must be balanced separately before being
assembled on the machine shaft. Refer to the balancing
instructions in chapter 2.2.5.
The shrinking of the half coupling onto the electrical
machine shaft end must be chosen, by the generator set
manufacturer, in such way as it should be removable for
maintenance (e.g. bearing change).
3.2.2 Stator attaching
Four plates on the chassis allow the unit to be attached
onto a pallet.
The fixing bolts must support the forces created by the
static and dynamic loads.
The machine may be positioned by means of 4 dowel pins.
The dowel pins make later realignment easier. (The use of
pins is optional).
The machine may be aligned through the use of 4 jacking-
screws. These jacking-screws allow the machine to be
positioned along the various axes.
3.3 MACHINE ALIGNMENT
3.3.1 General information concerning the alignment
3.3.1.1 General information
Alignment is intended to achieve coaxiality of the driving
and driven shafts under nominal operating conditions
(machine running; at its operating temperature).
The machine must be aligned according to the Leroy-
Somer standard and adhere to the manufacturer's
alignment standard for the drive machine.
When heating the machine has its shaft line which grow up.
Between stop and rotation the shaft axis location inside its
bearing is different. The total axis height elevation is
composed of the thermal elevation and of the bearing
elevation.
CAUTION:
THE ALIGNMENT MUST BE DONE TAKING INTO
ACCOUNT, THE CORRECTION FOR THE THERMAL
EXPANSION OF THE SHAFT.
The correct locating of the parts must be obtained by
inserting shims under the machine feet.
The double-bearing machines are mounted with bearings
(ball or roller) or Sleeve bearings. The axial clearance of
the bearings (if the machine has Sleeve bearings) must be
distributed as uniformly as possible, taking into account the
axial thermal expansion. The roller bearing machines with
a positioning bearing (standard machine) do not have axial
play.
The machines are delivered with the rotor mechanically
centred (axially and radially) in relation to the stator.
CAUTION:
THE ALIGNMENT STANDARDS OF MOTOR
MANUFACTURERS ARE FREQUENTLY MORE
ACCURATE THAN THOSE OF LEROY-SOMER.
3.3.1.2 Shaft elevation caused by heat rise
H(m) = Height of the machine axis
∆T= frame temperature rise = 30°C
λ = Coefficient of steel elongation = 0.012 °K-1
3.3.1.3 Elevation of the shaft of a roller bearing
machine
Caused by heat rise in the anti-friction bearing itself.
1 - cold, in rotation, or stopped
2 - hot, in rotation, or stopped
3.3.1.4 Inspection of the generator before alignment
Check the out-of-round of the generator shaft tip.
The total reading must be within a tolerance of 0.04 mm.
NOTE:
RUN OUT CHECK CAN BE INFEASABLE ON SLEEVE
BEARING MACHINE BECAUSE OF THE TOO HIGH
NECESSARY TURNING TORQUE NEEDED TO TURN
THE ROTOR.
3.3.1.5 Alignment procedure with the “double
concentricity” method
NOTE:
LASER DEVICES CAN MAKE THE JOB EASIER THAN
WITH THE PROCEDURE INDICATED.
This method is not sensitive to axial movements.
(Alignment methods using axial measurement are often
disrupted by a small axial movement of the rotor).
It is possible to check the alignment with the coupling
installed.
Equipment required:
Two rigid supports. The rigidity of the two supports is very
important.
Two micrometers
∆
H (mm) = λ
(°K
-1
)
. H
(m)
.
∆T
(°K)
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