Warning – Mammoth V-Cube User Manual
Page 19
3. Check each V-belt tension and adjust 3. the motor
base for correct amount according to the deflection
outlined in the Measuring Belt Tension procedure
below and in
start-up, daily for the first week until they should
acquire their permanent set, then monthly. All belts
should have approximately the same amount of de-
flection. Be aware of mismatched or worn belt sets.
If a belt must be changed, ensure to change all belts
on the same drive at the same time. Never replace
just one belt within a set.
Measuring Belt Tension
a. Measure the belt span with a span scale.
b. Divide the belt span by 64 to determine the belt
deflection needed to check tension.
c. Set the O-ring on the span scale to the required
deflection value.
d. Set the small O-ring at zero on the force scale.
e. Place the scale end of the tension checker
squarely on one belt at the center of the belt
span. Apply force on the plunger until the bot-
tom of the large O-ring is even with the top of
the next belt or until it is even with a straight
edge laid across the sheaves.
f. Read the force scale under the small O-ring to
determine the force required to give the needed
deflection.
g. Compare the force scale reading in Step F above
with the correct value for the belt style and cross
section. The force scale reading should be be-
tween the minimum and maximum values shown
in
h. If the deflection value is below the minimum,
tighten the belts. If the deflection value is above
the maximum, loosen the belts. The tension on
new belts should be checked during the first day
of operation, at the end of the first week and
monthly thereafter.
4. Check the fan and motor sheave alignment using a
straight edge along the outside edges of the sheaves
for equal sized fixed sheaves as shown in Figure 13
and Figure 14 at time of start-up, after 24 hours
of operation, monthly for the initial three months,
then every three months thereafter. When properly
aligned the straight edge should touch the full face
of both sheaves. With one adjustable and one fixed
sheave with unequal sizes, use a string placed at the
center grove of both sheaves pulled tight to check
alignment. Adjust sheaves for proper alignment and
set screws to proper torque.
5. Belt driven fan bearings are fitted with grease nipples
for lubrication. The grease quantity and lubrication
interval depends on bearing (fan size) and rpm and
are indicated in Tables 4 and 5. Use a premium qual-
ity lithium based grease conforming to NLGI Grade
2 or 3 (examples are: Mobil Mobilith AW2, Chevron
Amolith #2, Texaco Premium RB, Shell Alvania #2
or Esso Beacon #325). Clean the grease nipple first,
then rotate the fan shaft slowly by hand while add-
ing grease. The lubrication intervals are theoretical
and will depend on site conditions, hours of opera-
tion and temperature. It is recommended to make
periodic inspections of the bearings before these
theoretical intervals.
!
WARNING
Many of the following steps need to be performed with
the unit powered off and locked out. Disconnect the
main power switch to the unit before performing service
and maintenance procedures.
Table 3: Bearing set screw torque in lb-in
Set Screw
Diameter
Manufacturer
Link
Belt
Sealmaster SKF
McGill Dodge
#10
40
—
35
35
—
1/4
90
65
50
85
—
5/16
185
125
165
165
160
3/8
325
230
290
290
275
7/16
460
350
350
—
—
1/2
680
500
620
—
600
5/8
1,350
1,100
1,325
—
1,200
3/4
2,350
—
—
—
2,000
Split pillow block bearings are fixed to the shaft with tapered
sleeves and generally do not have set screws.
Figure 13: Equal sheave
size alignment
Lines must
be parallel
Center lines
must coincide
Fixed
sheave
Straight
edge
Adjustable
sheave
Figure 14: Unequal sheave
size alignment
VCES-V-CUBE-IOM-1A
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