Fan Drive System (Except Direct Drive Units) - BAC PCT Series Operation & Maintenance Manual

Fan Drive System (Belt Drive Units)
Belt Drive Power Train
The drive train consists of SPB belts, a fan sheave and a motor sheave.
The high efficiency belts provide the premium quality necessary for
evaporative cooling equipment.
Together these components provide a highly reliable system with
low maintenance requirements. The drive train should be inspected
periodically to check the belt tension, condition of the sheaves and
belt, and when necessary adjust the tension. The recommended service
intervals are specified elsewhere.
Inspection & Maintenance
The belt drive power train requires a periodic check of belt condition
and, when necessary, tension adjustment. The recommended service
intervals are as follows:
• Initial Start-Up:
– If the equipment was supplied in assembled major sections,
no servicing is required prior to initial startup since the drive
has been tensioned and aligned at the factory. If equipment
was supplied completely knocked down (CKD) then check drive
alignment & belt tensioning as per procedures outlined below.
• Seasonal Start-Up: Readjust the tension on the belt.
• Operation: After the first 24 hours of operation, readjust
the belt tension on a new unit start-up or installation of a
new belt. Thereafter, check the belt condition monthly, and
adjust tension as necessary. Readjust tension at least once
every three months.
• Belt tension check:
– Place a straight edge along the belt from sheave to
sheave as shown in Figure 3a, or use a tape measure as
shown in Figure 3b to measure belt deflection.
– Apply a moderate force by hand (approximately 2kg)
evenly across the width of the belt in the centre of the
span between the sheaves.
– There is adequate belt tension if the belt deflects
between 6mm and 9mm as shown in Figures 3a and 3b.
Detailed Component
Maintenance Procedures
Fan
Inspection & Maintenance
Fan Drive System
(Belt Drive Units)
Belt Drive Power Train
Inspection & Maintenance
WARNING: No service work should
be performed on the drive train
without first ensuring the fan
and pump motors have been
isolated, tagged and locked in
the off position.
6mm to 9mm
Figure 3a. Belt Tension with a Straight Edge
6mm to 9mm
Figure 3b. Belt Tension with a Tape Measure
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