CAMCORP SWF with Externally Mounted Fan - Manual (Page 43)

Table 1 - WHEEL SETSCREW TORQUES
Setscrew Size Carbon Steel Setscrew Torque*
Diameter (in.) lb.-in. lb.-ft.
1/2 600 50
5/8 -- 97
3/4 -- 168
* Stainless Steel setscrews are not hardened and should
not be tightened to more than 1/2 the values shown.
Table 2 - BEARING SETSCREW TORQUE, lb.-in.
Setscrew Manufacturer
Diameter Link-Belt Sealmaster SKF McGill Dodge
1/4 90 65 50 85 --
5/16 185 125 165 165 160
Note: Split pillow block bearings are fixed to the shaft with
tapered sleeves and generally do not have setscrews.
FAN MAINTENANCE
nyb fans are manufactured to high standards with quality mate-
rials and components. Proper maintenance will ensure a long
and trouble-free service life.
Do not attempt any maintenance on a fan unless the elec-
trical supply has been completely disconnected and
locked. In many cases, a fan can windmill despite removal of
all electrical power. The rotating assembly should be blocked
securely before attempting maintenance of any kind.
The key to good fan maintenance is regular and systematic
inspection of all fan parts. Inspection frequency is determined
by the severity of the application and local conditions. Strict
adherence to an inspection schedule is essential.
Regular fan maintenance should include the following:
1. Check the fan wheel for any wear or corrosion, as either
can cause catastrophic failures. Check also for the build-
up of material which can cause unbalance resulting in
vibration, bearing wear and serious safety hazards. Clean
or replace the wheel as required.
2. Check the V-belt drive for proper alignment and tension
(see section on V-belt drives). If belts are worn, replace
them as a set, matched to within manufacturer’s toler-
ances. Lubricate the coupling of direct-drive units and
check for alignment (see section on couplings).
3. Lubricate the bearings, but do not over lubricate (see the
bearing section for detailed specifications).
4. Ceramic-felt shaft seals require no maintenance, although
worn seals should be replaced. When lip-type shaft seals
are provided, lubricate them with "NEVER-SEEZ" or other
anti-seize compound.
5. During any routine maintenance, all setscrews and bolts
should be checked for tightness. See the table for correct
torques.
6. When installing a new wheel, the proper wheel-to-inlet
clearance must be maintained (see Figure 3 ).
WHEEL BALANCE
Airstreams containing particulate or chemicals can cause abra-
sion or corrosion of the fan parts. This wear is often uneven and
can lead to significant wheel unbalance over time. When such
wear is discovered, a decision must be made as to whether to
rebalance or replace the wheel.
The soundness of all parts should be determined if the original
thickness of components is reduced. Be sure there is no hidden
structural damage. The airstream components should also be
cleaned to remove any build-up of foreign material. Specialized
equipment can be used to rebalance a cleaned wheel that is
considered structurally sound.
Balance weights should be rigidly attached at a point that will
not interfere with the housing nor disrupt airflow. Remember
that centrifugal forces can be extremely high at the outer radius
of a fan wheel. Welding is the preferred method of balance
weight attachment. Be sure to ground the welder directly to the
fan wheel. Otherwise, the welding current could pass through
the fan bearings and damage them.
Figure 3
BEARINGS
Storage
Any stored bearing can be damaged by condensation caused
by temperature variations. Therefore, nyb fan bearings are
filled with grease at the factory to exclude air and moisture.
Such protection is adequate for shipment and subsequent
immediate installation.
For long term or outdoor storage, mounted bearings should be
regreased and wrapped with plastic for protection. Rotate the
fan wheel by hand at least every two weeks to redistribute
grease on internal bearing parts. Each month the bearings
should be purged with new grease to remove condensation,
since even a filled bearing can accumulate moisture. Use cau-
tion when purging, as excessive pressure can damage the
seals. Rotate the shaft while slowly adding grease.
Operation
Check the setscrew torque before start-up (see table for correct
values). Since bearings are completely filled with grease at the
factory, they may run at an elevated temperature during initial
operation. Surface temperatures may reach 180°F. and grease
may bleed from the bearing seals. This is normal and no
attempt should be made to replace lost grease. Bearing surface
temperatures will decrease when the internal grease quantity
reaches a normal operating level. Relubrication should follow
the recommended schedule.
Page 4
WHEEL-INLET CLEARANCE