Serviceable components, Routine maintenance & operation, Fan operation – Greenheck Fan Vektor-CD Direct or Belt Drive The Vektor-CD fan 47555 User Manual

Page 11: V-belt drives

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Vektor-CD Centrifugal Laboratory Exhaust

®

Serviceable Components

Windband

Bypass Air
Plenum

Bypass
Damper

Weatherhood

Isolation
Damper

Nozzle

Fan Assembly

Roof Curb or Structural Support

Fan Operation

All fans should be run every thirty (30) days, or at least
“bumped” every thirty days. It is preferred that each
fan is run as this causes all electrical and mechanical
components to get up to temperature, displacing any
formed condensation, redistributes load on bearings,
and redistributes grease in the bearings (motor and
shaft bearings).

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. Use a set of matched belts whenever
possible. 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 halfway between sheave
centers is 1/64 inch for each inch of 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.

Routine Maintenance & Operation

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. Bypass air dampers should be checked for

freedom of operation and wear.

3. Wheel, housing, bolts and set screws on the

entire fan should be checked for tightness.

4. Any dirt accumulation on the wheel or in the

housing should be removed to prevent unbalance
and possible damage.

5. Inspect fan impeller and housing looking for

fatigue, corrosion, or wear.

CAUTION

When operating conditions of the fan are to be
changed—speed, pressure, temperature, etc.—
consult Greenheck to determine if the unit can
operate safely at the new conditions.

Belt Span

Deflection = Belt Span

64

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