Maintenance; V-Belt Drive; V-Belt Replacement - Greenheck DFD Series Installation, Operation And Maintenance Manual

Maintenance

DANGER
Disconnect and secure to the "OFF" position all
electrical power to the fan prior to inspection or
servicing. Failure to comply with this safety precaution
could result in serious injury or death.
DANGER
Pour écarter les risques de blessure grave ou de mort,
débrancher et verrouiller l'alimentation électrique en
position « Arrêt » avant tout contrôle ou entretien.
Once the unit has been put into operation, a routine
maintenance schedule should be set up to accomplish
the following:
1. Lubrication of bearings and motor.
2. Wheel, housing, bolts and set screws on the entire
fan should be checked for tightness.
3. Any dirt accumulation on the wheel or in the housing
should be removed to prevent unbalance and
possible damage.
4. Springs should be checked for breaks and
fatigue. Rubber isolators should be checked for
deterioration.
5. Inspect fan impeller and housing looking for fatigue,
corrosion or wear.
IMPORTANT
Changing the belts or drives can significantly increase
the amp draw of the motor. If changes are made to
the drives or belts, the amps must be checked to
assure no overamping.
V-Belt Drives
V-belt drives must be checked on a regular basis
for wear, tension, alignment and dirt accumulation.
Premature or frequent belt failures can be caused by
improper belt tension (either too loose or too tight)
or misaligned sheaves. Abnormally high belt tension
or drive misalignment will cause excessive bearing
loads and may result in failure of the fan and/or motor
bearings. Conversely, loose belts will cause squealing
on start-up, excessive belt flutter, slippage and
overheated sheaves. Either excessively loose or tight
belts may cause fan vibration.
When replacing V-belts on multiple groove drives,
all belts should be changed to provide uniform drive
loading. Do not pry belts on or off the sheave. Loosen
belt tension until belts can be removed by simply lifting
the belts off the sheaves. After replacing belts, ensure
that slack in each belt is on the same side of the drive.
Belt dressing should never be used.
Do not install new belts on worn sheaves. If the sheaves
have grooves worn in them, they must be replaced
before new belts are installed.
The proper tension for operating a V-belt drive is
the lowest tension at which the belts will not slip at
peak load conditions. Belts are adjusted by raising or
lowering the motor pivot plate. For initial tensioning, the
proper belt deflection half-way between sheave centers
is 1/64 of the belt span. For example, if the belt span
is 64 inches, the belt deflection should be 1 inch using
moderate thumb pressure at
mid-point of the drive.
Check belt tension two
times during the first 24
hours of operation and
periodically thereafter.

V-Belt Replacement

The V-belt drive components, when supplied by
Greenheck, have been carefully selected for this unit's
specific operating condition. Changing V-belt drive
components could result in unsafe operating conditions
which may cause personal injury or failure of fan
components.
1. Remove the protective coating from the end of the
fan shaft using mineral spirits or another similar
solvent. Check to ensure that the shaft is free of
nicks and burrs.
2. Slide sheaves on shafts. Do not drive sheaves on as
this may result in bearing damage.
3. Align fan and motor sheaves with a laser, straight-
edge or string and tighten.
4. Place belts over sheaves. Do not pry or force belts,
as this could result in damage to the cords in the
belts.
5. Adjust the tension until the belts appear snug. Run
the unit for a few minutes (refer to unit start-up
section) and allow the belts to "set" properly.
6. With the fan off, adjust the belt tension by moving
the motor pivot plate. (Belts are adjusted by raising
or lowering the motor pivot plate). When in operation,
the tight side of the belts should be in a straight line
from sheave to sheave with a slight bow on the slack
side.
Belt Span
Deflection =
64
Belt Span
Mixed Flow 9