OM--04760
SELF-PRIMING CENTRIFUGAL PUMPS
PAGE B -- 8
INSTALLATION
When checking alignment, disconnect
the power source to ensure that the
pump will remain inoperative.
Adjusting the alignment in one direction
may alter the alignment in another direc-
tion. check each procedure after altering
alignment.
Coupled Drives
When using couplings, the axis of the power
source must be aligned to the axis of the pump
shaft in both the horizontal and vertical planes.
Most couplings require a specific gap or clearance
between the driving and the driven shafts. Refer to
the coupling manufacturer’s service literature.
Align spider insert type couplings by using calipers
to measure the dimensions on the circumference
of the outer ends of the coupling hub every 90 de-
grees. The coupling is in alignment when the hub
ends are the same distance apart at all points (see
Figure 5).
Figure 5. Aligning Spider-Type Couplings
Align non-spider type couplings by using a feeler
gauge or taper gauge between the coupling halves
every 90 degrees. The coupling is in alignment
when the hubs are the same distance apart at all
points (see Figure 6).
Figure 6. Aligning Non-Spider Type Couplings
Check parallel adjustment by laying a straightedge
across both coupling rims at the top, bottom, and
side. When the straightedge rests evenly on both
halves of the coupling, the coupling is in horizontal
parallel alignment. If the coupling is misaligned,
use a feeler gauge between the coupling and the
straightedge to measure the amount of misalign-
ment.
V-Belt Drives
When using V-belt drives, the power source and
the pump must be parallel. Use a straightedge
along the sides of the pulleys to ensure that the pul-
leys are properly aligned (see Figure 7). In drive
systems using two or more belts, make certain that
the belts are a matched set; unmatched sets will
cause accelerated belt wear.
MISALIGNED:
SHAFTS
NOT PARALLEL
MISALIGNED:
SHAFTS
NOT IN LINE
ALIGNED: SHAFTS
PARALLEL AND
SHEAVES IN LINE
Figure 7. Alignment of V-Belt Driven Pumps
Tighten the belts in accordance with the belt manu-
facturer’s instructions. If the belts are too loose,
they will slip; if the belts are too tight, there will be
excessive power loss and possible bearing failure.
