Greenheck Housed Plenum Array , Plug and Plenum Fans (475405) - Manual (Page 7)

7 Housed Plenum Array, Plug and Plenum
V-Belt Drives
V-Belt Drive Installation
The V-belt drive components, when supplied by
Greenheck, have been carefully selected for this unit’s
specific operating condition.
IMPORTANT
Changing V-belt drive components could result
in unsafe operating conditions which may cause
personal injury or failure of the following components:
• Fan shaft
• Fan wheel
• Bearings
• V-belt
• Motor
1. Remove the protective coating from the end of the
fan shaft and assure that it is free of nicks and burrs.
2. Check fan and motor shafts for parallel and angular
alignment.
3. Slide sheaves on shafts, Do not
drive sheaves on as this may
result in bearing damage.
4. Align fan and motor sheaves
with a straight edge or
string, and tighten.
5. Place belts over sheaves.
Do not pry or force belts,
as this could result in
damage to the cords in
the belts.
6. Adjust the tension until the belts appear snug. Run
the unit for a few minutes (see section on Unit Start-
Up) and allow the belts to seat properly. Refer to
Greenheck’s Product Application Guide “Measuring
Belt Tension” for additional information.
7. With the fan off, adjust the belt tension by moving
the motor base. (See belt tensioning procedures in
the maintenance section of this manual). 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.
The adjustable motor pulley is set at the factory for
the fan RPM specified by the customer. Fan RPM can
be increased by closing or decreased by opening the
adjustable motor pulley. Multi-groove variable pitch
pulleys must be adjusted an equal number of turns
open or closed. Any increase in fan speed represents a
substantial increase in load on the motor.
To avoid motor overheating and possible burnout, motor
load amperes should always be checked and compared
to nameplate rating when fan speed is increased.
Alignment of Pulleys and Belts
Check pulleys and belts for proper alignment to avoid
unnecessary belt wear, noise, vibration and power loss.
Motor and drive shafts must be parallel and pulleys in
line as shown.
Do not force belt(s). Forcing the
belt(s) will break the cords and
cause belt failure
Deflection = Belt Span
64
Slack
Side
Belt
Span
CORRECT WRONG
WRONG WRONG
CORRECT WRONG WRONG WRONG
FAN FAN
MOTOR MOTOR
Aligning Sheaves
with a Straight Edge