COOK AVA - Manual (Page 7)

7
• Inspect springs and rubber isolators for deterioration
and replace as needed.
• Inspect for cleanliness. Clean exterior surfaces only.
Removing dust and grease on motor housing
assures proper motor cooling. Removing dirt from
the wheel and housing prevent imbalance and dam-
age. housing prevent imbalance and damage.
Lubrication - Fan Bearings
Vane Axial bearings are lubricated through a grease fit-
ting on the exterior of the fan housing and should be
lubricated by the schedule, Lubrication Conditions Chart.
For best results, lubricate the bearing while the fan is in
operation. Pump grease in slowly until a slight bead
forms around the bearing seals. Excessive grease can
burst seals thus reducing bearing life.
Before lubricating, the grease nipple and immediate
vicinity should be thoroughly cleaned without the use of
high pressure equipment. The grease should be supplied
slowly as the bearing rotates until fresh grease slips past
the seal. Excessive pressure should be avoided to pre-
vent seal damage.
Use no more than three injections with a hand-oper-
ated grease gun.
Exceptions to the greasing interval chart:
• Periodic Applications (any break of one week or
more): it is recommended that full lubrication be per-
formed prior to each break in operation.
• Higher Temperature: it is recommended to halve the
intervals for every 30
°F increase in operating tempera-
ture above 120
°F not to exceed 230°F for standard bear-
ings; High Temperature bearings (optional) can operate
up to 400
°F.
• Vertical Shaft: it is recommended that the intervals
should be halved.
Loren Cook Company uses petroleum lubricant in a
lithium base. Other types of grease should not be used
unless the bearings and lines have been flushed clean. If
another type of grease is used, it should be a lithium-
based grease conforming to NLGI grade 2 consistency.
A NLGI grade 2 grease is a light viscosity, low-torque,
rust-inhibiting lubricant that is water resistant. Its temper-
ature range is from -30
°F to +200°F and capable of inter-
mittent highs of +250
°F. For temperatures above 250°F
Mobiltemp SHC 32 is recommended.
Lubrication - Motor Bearings
Motors are provided with prelubricated bearings. Any
lubrication instructions shown on the motor nameplate
supersede instructions below.
Motor bearings without provisions for relubrication will
operate up to 10 years under normal conditions with no
maintenance. In severe applications, high temperatures
or excessive contaminates, it is advisable to have the main-
tenance department disassemble and lubricate the bear-
ings after 3 years of operation to prevent interruption of
service.
For motors with provisions for relubrication, follow inter-
vals of the table below.
Motors are provided with a polyurea mineral oil NGLI #2
grease. All additions to the motor bearings are to be with a
compatable grease such as Exxon Mobil Polyrex EM and
Chevron SRI.
The above intervals should be reduced to half for vertical
shaft installations.
Motor Services
Should the motor prove defective within a one-year
period, contact your local Loren Cook representative or
your nearest authorized electric motor service representa-
tive.
Changing Shaft Speed
All belt driven AF fans with motors up to and including 5
HP are equipped with variable pitch pulleys. To change the
fan speed, perform the following:
a. Loosen setscrew on driver (motor) pulley and remove
key, if equipped.
b. Turn the pulley rim to open or close the groove facing.
If the pulley has multiple grooves, all must be adjusted
to the same width.
c. After adjustment, inspect for proper belt tension.
Speed Reduction
Open the pulley in order that the belt rides deeper in
the groove (smaller pitch diameter).
Speed Increase
Close the pulley in order that the belt rides higher in
the groove (larger pitch diameter). Ensure that the RPM
limits of the fan and the horsepower limits of the motor
are maintained.
The AVAB and VAB have standard fixed pitch
sheaves. To change speeds, consult factory.
Pulley and Belt Replacement
a. Remove pulleys from their respective shafts.
b. Clean the motor and fan shafts.
c. Clean bores of pulleys and coat the bores with heavy
oil.
d. Remove grease, rust, or burrs from the pulleys and
shafts.
e. Remove burrs from shaft by sanding.
f. Place fan pulley on fan shaft and motor pulley on its
shaft. Damage to the pulleys can occur when exces-
sive force is used in placing the pulleys on their
respective shafts.
Relubrication Intervals
Service
Conditions
NEMA Frame Size
Up to and
including 184T
213T-365T 404T and larger
1800 RPM
and less
Over 1800
RPM
1800 RPM
and less
Over 1800
RPM
1800 RPM
and less
Over 1800
RPM
Standard 3 yrs. 6 months 2 yrs. 6 months 1 yr. 3 months
Severe 1 yr. 3 months 1 yr. 3 months 6 months 1 months
Lubrication Conditions Chart
Fan Class Fan Status
Fan Operating
Temperature (F)
Maximum Interval
(operational hrs)
Inlet Vane
Axial Blowers
Normal Conditions
(Clean, Dry & Smooth)
up to 120 4,500
121 to 160 1,500
161 to 200 700
201 to 400 (*) 200
Extreme Conditions
(Dirty/Wet/Rough)
up to 160 700
161 to 200 400
201 to 400 (*) 200