Care should be taken not to overtighten V-belt
drive. Excessive belt tension overloads fan and
motor bearings. It is much less expensive to
replace belts worn from slippage than to
replace bearings damaged from excessive
loading.
Fans shipped completely assembled have had V-belt
drive aligned at the factory. Alignment should be
rechecked before operation as a precaution due to
handling during shipment.
1. Be sure sheaves are locked in position.
2. Key should be seated firmly in keyway.
3. Place straight edge or taut cord across faces of
driving and driven sheaves to check alignment. The
motor and fan shafts must be parallel and V-belts
must be at right angles to the shafts.
4. Start the fan. Check for proper rotation. Run fan at full
speed. A slight bow should appear on slack side of
belt. Disconnect power and adjust belt tension by
adjusting motor on its sliding base. All belts must have
some slack on one side.
5. If belts squeal at start up, they may be too loose.
6. When belts have had time to seat in the sheave
grooves, then readjust belt tension (2-3 days).
4
Conditions Around Bearing Operating Temperature of Fan **Greasing Intervals
Fairly Clean up to 120 °F 6-12 months
120°-160°F 2-3 months
160°-200°F plus* 1-2 months
Moderate to up to 160°F 1-2 months
Extremely Dirty 160°-200°F plus* 2-4 weeks
Cold Storage Room every defrosting period or
no more than 4 months
*For fan applications over 200°F: greasing intervals should be from several days to 2 weeks, depending
on the temperature.
**For vertical installations, greasing intervals should be twice as frequent as table values.
The following greases, or one that is equivalent to the general description, are recommended for the following
temperatures or excessive moisture applications.
Operating Conditions Use Grease Equivalent to these Grades
Esso-Beacon #325 (-65°F)
Temperatures -65°F to 0°F Mobil Grease #28 (-65°F)
Shell Oil Aeroshell No. 7 (-100°F)
General Description: Versatile multipurpose microgel thickened synthetic hydrocarbon grease with corrosion
inhibitors, anti-oxidant additives, water resistance tendencies and EP characteristics.
Temperature 0°F to 200°F inclusive Mobil Oil - Mobilux EP #2
(Also use for heavy condensation Shell Oil - Shell Alvania EP #2
or direct splash of water) Chevron - Chevron SRI #2
General Description: Multipurpose NLGI#2 grease from lithium soap with EP characteristics, rust inhibitors,
anti-oxidant additives and good water resistance tendencies.
Temperatures over 200°F Dow Corning-DC44 (400°F)
(Not compatible with non-silicon based greases)
General Description: Versatile multipurpose microgel thickened synthetic hydrocarbon grease with corrosion
inhibitors, anti-oxidant additives, water resistance tendencies and EP characteristics.
Table #3 (See Bearing Maintenance, page 5.)
VII. V-BELT DRIVES
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