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MOTOR DRIVEN PUMPS
COUPLING ALIGNMENT
The pump must be directly coupled to a gear reducer and/or
driver with a flexible coupling. Verify coupling alignment after
installation of new or rebuilt pumps. Both angular and parallel
coupling alignment MUST be maintained between the pump,
gear, motor, etc. in accordance with manufacturer’s
instructions. See Figure 5.
1. Parallel alignment: The use of a laser alignment tool or
dial indicator is preferred. If a laser alignment tool or dial
indicator is not available, use a straightedge. Turn both
shafts by hand, checking the reading through one
complete revolution. Maximum offset must be less than
.0005" (0.127 mm).
2. Angular alignment: Insert a feeler gauge between the
coupling halves. Check the spacing at 90° increments
around the coupling (four checkpoints). Maximum
variation must not exceed 0.005" (0.127 mm). Some
laser alignment tools will check angular alignment as
well.
3. Replace the coupling guards after setting alignment.
Figure 5 – Coupling Alignment
V-BELT DRIVE
For installation of Blackmer V-belt units, first mount the pump
and the motor base to the unit base. Do not fully tighten the
motor mounting bolts until properly installing and adjusting the
belts as follows:
1. Wipe the cone surface of the pump QD hub (152A) and
the inside of the pump sheave hub with a clean cloth
moistened with a light grade of machine oil. This will
allow for a more uniform draw and prevent the cone
surfaces from “freezing” before being tightened.
2. With the pump shaft key (35) in place, align the key seat
and slide the QD hub (152A) on the shaft, flange end
first. Slide the large end of the sheave (152) bore over
the taper on the QD hub. Insert the three sheave
capscrews (152G) through the clearance holes in the
sheave, and start them into the tapped holes of the QD
hub (152A). Repeat this procedure to assemble the
motor QD hub (152E) and sheave (152D).
3. To install the belts (181), shorten the center distance of
the drive by moving the motor towards the pump, until the
belts can be put on the sheaves (152 & 152D) without
forcing.
4. Align the sheaves so that the faces are parallel, then
snug up the sheave capscrews (152C & G).
5. Measure the span length as shown in Figure 6.
6. Adjust the motor base (183) and apply a specified force
(see Table 1) against the belt, at the center of the span,
so that the belt is deflected 1/64 inch (0.04 mm) for every
inch (25.4 mm) of span. For example, the deflection of a
20 inch (508 mm) span would be 20/64 or 5/16 inch (7.9
mm). Refer to Table 1 for the deflection force of a
properly tensioned drive. A new set of belts should be
initially tensioned to the upper limit.
SMALL SHEAVE
OUTSIDE DIAMETER
BELT DEFLECTION FORCE
Minimum Maximum
2.5” to 4.5”
(63 mm to 114 mm)
3.0 lbs
(1.4 kgs)
4.75 lbs
(2.2 kgs)
4.75” to 7.0”
(121 mm to 178 mm)
4.0 lbs
(1.8 kgs)
6.0 lbs
(2.7 kgs)
Table 1 - Deflection Force Per Belt
7. Check again to ensure the sheaves (152 & 152D) are
parallel, then tighten the sheave capscrews (152C &
152G), the motor mounting nuts (183B) and the adjusting
screw locknut (183B).
8. Assemble the belt guard (182) and the belt guard brace
(182A) to the unit base (32).
Operation without guards in place can
cause serious personal injury, major
property damage, or death.
Do not operate
without guard
in place
9. Check the belt tension after 24-48 hours of operating.
Recheck the tension periodically and tighten the belts as
required. DO NOT overtighten belts. Inspect belts
periodically for signs of excessive wear, and replace as
required.
V-BELT DISASSEMBLY
1. Remove the belt guard (182) and the guard base (182A).
Loosen the adjusting screw locknut (183B) on the motor
base (183) and the motor mounting nuts.
2. Ease the tension on the belts (181) by moving the motor
towards the pump to shorten the center distance of the
drive. Remove the belts by sliding them over the sheaves
(152 & 152D). DO NOT force the belts over the grooves.
3. To remove the sheave from the hub, first remove the
three sheave capscrews (152C or 152G). Then screw
two of the capscrews into the threaded holes in the
sheave hub (152A or E). If the cone grip is hard to break
loose, tap the end of the shaft or the QD hub with soft-
faced mallet while maintaining pressure on the screw.
4. The QD hub should slide smoothly off the shaft. If it is
tight on the shaft, gently pry it loose with a screwdriver or
a small wedge placed in the split part of the flange.
Refer to Blackmer V-Belt Parts List and Instructions for
V-belt drive and guard part numbers.
Figure 6 –
V-Belt Adjustment
