BAC PCT Series, Operation & Maintenance Manual

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Figure 5. Drive Alignment
Detailed Component
Maintenance Procedures
Fan Drive System
(Belt Drive Units)
Inspection & Maintenance
Alignment
Fan Drive System
(Direct Drive Units)
Drive Train
WARNING:
Check to ensure the
controls for the fan motor are
set to allow a maximum of six
on-off cycles per hour to prevent
motor overload.
Alignment
• Check the drive alignment annually to ensure maximum belt life.
• Drive alignment check and adjustment:
– Place a straight edge across the driver and the driven sheaves as
shown in
Figure 5 .
– The straight edge should contact all four points as shown in
Figure 5
indicating that the drives are properly aligned.
– There should be no more than 1.5mm deviation from four points
of contact.
– In case of realignment, loosen the motor sheave and align it with
the fan sheave. Allow 6mm for draw-up as the bushing screw is
retightened.
Fan Drive System (Direct Drive Units)
Drive Train
The standard fan motor used
on direct driven PCT towers
is a TEAO (Totally Enclosed
Air Over) motor. The motor
has permanently lubricated
ball bearings and special
moisture protection on the
bearings, shaft, and ings. The
only servicing required during
operation is to clean the outside
surface of the motor at least
quarterly to ensure proper
motor cooling. After prolonged
shutdowns, the motor insulation
should be checked with a
“megger” insulation tester
before restarting the motor.
Figure 6. Belt Tensioning