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Step 13 — Check Belt Tension
Measure the belt span length as shown in Fig. 55. Calculate the re-
quired deflection by multiplying the belt span length by
example, if the belt span length is 32 inches: 32 x
deflection.
BELT FORCE — DEFLECTION METHOD
Check the belt tension with a spring-force belt force deflection
gauge (available from drive belt manufacturer).
1. Place a straightedge along the belt between the two pul-
leys. Measure the distance between the motor shaft and
the blower shaft.
2. Set the tension gauge to the desired tension (see Table 1 in
Fig. 55). Place the large O-ring at that point.
3. Press the tension checker downward on the belt until the
large O-ring is at the bottom of the straightedge.
4. Adjust the belt tension as needed.
Adjust belt tension by loosing the motor mounting plate front bolts
and rear bolt (see Fig. 56) and slide the plate towards the fan (to
reduce tension) or away from the fan (to increase tension). Ensure
the blower shaft and motor shaft are parallel to each other (pulleys
aligned). Tighten all bolts securely when finished.
BELT TENSION METHOD
Requires belt tension gauge that measures tension in belt in units
of lbs force.
Fig. 54 — EconoMi$er IV Wiring
/
. For
1
64
/
=
/
inch
1
1
64
2
TORQUE ALL SHEAVE SET SCREWS TO 110-130 in. lbs
BELT
CROSS
SECTION
A, AX
B, BX
BELT CONDITION
44
BELT DEFLECTION FORCE - SEE TABLE 1
DEFLECTION = BELT SPAN
SET
SCREW
BELT DEFLECTION FORCE (LBS)
SMALLEST
UNNOTCHED
SHEAVE
BELTS
DIAMETER
USED
3.0-3.6
3.7
3.8-4.8
4.5
5.0-7.0
5.4
3.4-4.2
—
4.4-5.6
5.3
5.8-8.6
6.3
Table 1
TENSION FORCE IN BELT (LBS)
New
Used
Table 2
Fig. 55 — V-Belt Force Label
64
STRAIGHT
EDGE
SET
SCREW
NOTCHED BELTS
NEW
USED
NEW
5.5
4.1
6.1
6.8
5.0
7.4
8.0
5.7
8.4
—
4.9
7.2
7.9
7.1
10.5
9.4
8.5
12.6
100
80
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