Flowserve FRBH - Manual (Page 22)

FRBH, FRBHX AND FRBHS USER INSTRUCTIONS ENGLISH 71569178 10-04
Page 22 of 54
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4.5 Initial alignment
4.5.1 Thermal expansion
The pump and motor will normally
have to be aligned at ambient temperature and
should be corrected to allow for thermal expansion at
operating temperature. In pump installations
involving high liquid temperatures, the unit should be
run at the actual operating temperature, shut down
and the alignment checked immediately.
4.5.2 Alignment methods
Ensure pump and driver are isolated
electrically and the half couplings are disconnected.
The alignment MUST be checked.
Although the pump will have been aligned at the
factory it is most likely that this alignment will have
been disturbed during transportation or handling. If
necessary, align the motor to the pump, not the pump
to the motor.
4.5.2.1 Direct Driven Units:
The importance of accurate alignment of pump and
driver shafts cannot be overemphasized.
IMPROPER ALIGNMENT IS THE PRIMARY CAUSE
OF VIBRATION PROBLEMS AND REDUCED
BEARING LIFE.
A flexible coupling is used to compensate for slight
changes in alignment that occur during normal
operation and is not used to correct for installation
errors. Install the pump and driver half couplings in
accordance with the coupling manufacturer's
instructions. Note that the coupling hub faces are not
always mounted flush with the ends of the shafts. Place
the driver on the baseplate such that the correct spacing
is obtained between the two half couplings. In the case
of electric motors, such as those with sleeve bearings, it
may be necessary to run the motor to establish the rotor
magnetic center. Consult the manufacturer's instruction
manual for details.
The purpose of the alignment procedure is to ensure
that the pump and driver shafts are in parallel and
angular alignment under the normal operating
conditions of load and temperature.
When the pump coupling and driver are assembled at
the factory, the units are aligned prior to shipment.
However, baseplates can be sprung or distorted during
shipment or installation and the alignment must be
checked before the unit is put in service. The coupling
spacer must be removed to make this check.
For pumps and drivers that operate at different
temperatures compensation must be made at the initial
alignment stage (when the units are at the same
temperature) to allow for thermal expansion during
operation. Consult the instruction manual supplied with
the driver for the manufacturer's recommendations.
Shaft alignment is greatly simplified by the use of a dial
indicator, or with extension rods and a magnetic base.
Before taking readings, ensure that the pump and driver
mounting bolts are secure, and that the thrust bearing
housing is properly aligned in the bearing frame or
cartridge. (See Section VII- Maintenance).
Parallel Alignment: