Universal Single Width Fans8
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. Multigroove 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 in Figure 1.
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
Figure 1
V-Belt Drives
V-Belt Drive Installation
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 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 and
allow the belts to “set” properly.
6. With the fan off and disconnect locked out, adjust the belt tension by moving 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.
Aligning Sheaves with
a Straight Edge
Measuring Belt Tension (FA/127-11)
www.greenheck.com/resources/library/application-articles
To Next Page
Loading...
Need help?
General
