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Series L: Models LB, LBP, LD, and LDP
®
10. The adjustable motor pulley is factory set for
the RPM specified. Speed can be increased by
closing or decreased by opening the adjustable
motor sheave.
11. Two groove variable pitch pulleys must be
adjusted an equal number of turns open or
closed.
12. Any increase in speed represents a substantial
increase in the horsepower required by a unit.
13. Motor amperage should always be checked to
avoid serious damage to the motor when speed
is varied.
Maintenance
Motor maintenance is generally limited to cleaning
and lubrication (where applicable). Cleaning should
be limited to exterior surfaces only. Removing dust
buildup on motor housing ensures proper motor
cooling.
Greasing of motors is only intended when fittings
are provided. Many fractional hp motors are
permanently lubricated and should not be lubricated
further. Motors supplied with grease fittings should
be greased in accordance with manufacturers’
recommendations. Where motor temperatures do not
exceed 104ºF (40ºC), the grease should be replaced
after 2000 hours of running time as a general rule.
Wheels require very little attention when moving
clean air. Occasionally, oil and dust may accumulate
causing imbalance. When this occurs, the wheel and
housing should be cleaned to ensure smooth and
safe operation.
All fasteners should be checked for tightness each
time maintenance checks are performed prior to
restarting unit.
A proper maintenance program will help these units
deliver years of dependable service.
Belt/Bearing Maintenance
1. Belts tend to stretch after a period of time. They
should be checked periodically for wear and
tightness. When replacing belts, use the same
type as supplied with the unit.
2. Matched belts should always be used on units
with multi-groove pulleys.
3. For belt replacement, loosen the tensioning
device far enough to allow removal of the belt
by hand. Do not force belts on or off. This may
cause cords to break, leading to premature belt
failure.
4. Once installed, adjust belts as shown in “Pre-
Starting Checks.”
5. Shaft bearings can be classified in two groups:
relubricating and non-relubricating. All bearings
are factory lubricated and require no further
lubrication under normal use (between -20ºF
and 180ºF (-29° to 82°C) in a relatively clean
environment).
6. Units installed in hot, humid or dirty locations
should be equipped with special bearings.
These bearings will require frequent lubrication.
Caution should be employed to prevent
overpacking or contamination.
7. Grease fittings should be wiped clean. The
unit should be in operation while lubricating.
Extreme care should be used around moving
parts.
8. Grease should be pumped in very slowly until a
slight bead forms around the seal. A high-grade
lithium base grease is recommended.
9. Direct drive units require little maintenance
except for cleaning, wheel alignment, and oiling
according to motor label instructions.
IMPORTANT
Adjust (tighten) belt tension after the first
24-48 hours of operation.
Belt Span
G
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CORRECT WRONG WRONGWRONG
64
Deflection =
Belt Span
Figure 6
WARNING
Always disconnect, lock and tag power source before
servicing. Failure to disconnect power source can
result in fire, shock or serious injury.
WARNING
Uneven cleaning of the wheel will produce an out of
balance condition that will cause vibration in the fan.
WARNING
This unit should be made non-functional when
cleaning the wheel or housing (fuses removed,
disconnect locked off).