Coupling Alignment - Boulton Pumps ESK Series Instruction For Operation And Maintenance

2.3.4. Coupling Alignment

For a trouble free service life of the pumping unit the
most important factor is aligning the coupling properly.
The main reason for vibration, noisy operation, warming bearings and
overloading is an unaligned or misaligned coupling. Therefore the coupling
should be correctly aligned and be checked frequently.
A flexible coupling should never be expected to correct misalignment. A
FLEXIBLE COUPLING IS NOT A CURE FOR MISALIGNMENT AT ALL AND IT
DOES NOT COMPENSATE FOR EXCESSIVE MISALIGNMENT. A flexible
coupling will only compensate for small amount of misalignment.
"Coupling Alignment" means to secure the motor and
pump rotation axes on the same straight line. ESK series
pumps are dispatched from our factory after the coupling alignment is
precisely secured if supplied with driver and baseplate. A certain amount of
deformation of the baseplate is possible during handling and transit. For this
reason, regardless of the excellent alignment made at factory, THE PUMP
AND DRIVER HAVE TO BE REALIGNED DURING INSTALLATION.

Two pieces of minimum 100 mm long metal stripes with straight edge
(steel ruler) and a precise calliper are needed to align the coupling
(special instruments must be used for a very fine and precise
alignment).

There may be two forms of errors for coupling alignment:
a) Angular error.
b) Parallel sliding error.

To check the angular error, the gap between the coupling halves must
be the same at all points horizontally and vertically.

To control parallel sliding error, straight edged steel ruler is pressed
down on one half of the coupling in parallel to the axis. It is checked
against the other half. Straight edge must touch to the both half
couplings completely same at all points in each vertical and horizontal
planes (Fig.3).

Alignment errors can be either on vertical plane or horizontal plane. On
vertical plane alignment is corrected by inserting shims under the pump
or motor foot, and on horizontal plane alignment is corrected by sliding
the pump and/or motor horizontally sideways by using the gaps at
mounting holes. Fig. 4a, 4b, 4c, 4d show alignment of coupling step by
step.
Following any alternation, each alignment should be
rechecked because any movement due to an adjustment
in one direction may cause misalignment in another.
Fig. 4a. Angle error in horizontal plane and to settle
Fig. 4b. Angle error in vertical plane and to settle
Fig. 4c. Parallel sliding error in horizontal plane and to
settle
Fig. 4d. Parallel sliding error in vertical plane and to settle
13
Fig. 3. Aligning a flexible coupling