GLOBEAIRE RDD Manual De Instalación, Operación Y Mantenimiento página 18

Pre-Starting Checks
1. Check all fasteners and set screws for tightness.
The wheel should rotate freely and be aligned as
shown in Figure 7 below.
Wheel Overlap and Gap Dimensions
Model Size
RDD 070-095
RDD 99-163
RDB 081-161
RDB 180-240
RDB 260-300
G
Figure 7
2. Wheel position is preset and the unit is test run at
the factory. Movement may occur during shipment
and realignment may be necessary.
3. Only RDD model - Centering wheel across inlet
can be accomplished by loosening the set screws
in the wheel and moving the wheel to the desired
position.
RDD and RDB models - If further alignment is
needed, loosen shroud bolts and move shroud
and motor to align wheel over inlet properly.
Wheel and inlet cone overlap can be adjusted
by loosening the set screws in the wheel and
moving the wheel to the desired position. For
both RDD and RDB models with wheel hubs and
shaft pulleys utilizing a tapered bushing interface,
reference page 9 for the tapered bushing removal
and move the wheel to the desired position.
Fan RPM should be checked and verified with a
tachometer.
4. Check wheel rotation (viewing from the shaft
side) by momentarily energizing the unit. Rotation
should be clockwise as shown in Figure 8 and
correspond to rotation decal on the unit. If wheel
rotation is incorrect, reverse two of the wiring
leads or check motor wiring for single phase.
6 Roof Mounted Downblast Fans
Overlap Gap
in. (mm) in. (mm)
3 ⁄32 (2)
–
1/4 (6) –
1/4 (6) –
3/8 (10) –
1/2 (13) –
H
Wheel Rotation
Figure 8
Clockwise
WARNING
Airflow
Correct direction of wheel rotation is critical. Reversed
rotation will result in poor air performance, motor
overloading and possible burnout.
WARNING
The fan has been checked for mechanical noises at
the factory prior to shipment. If mechanical noise
should develop, suggested corrective actions are
offered in the Troubleshooting section.
IMPORTANT
Over tightening will cause excessive bearing wear and
noise. Too little tension will cause slippage at startup
and uneven wear.
Model RDB Pre-Starting Belt Tension
Checks
5. Always loosen tension enough to install belts
without stretching. Do not force belt(s) see Figure
9. Forcing the belts will break the cords and cause
belt failure.
Do not force belt(s). Forcing the belt(s)
will break the cords and cause belt failure.
Figure 9
6. For units with two groove pulleys, adjust so the
tension is equal in both belts.
7. If adjustments are made, it is very important to
check the pulleys for proper alignment. Misaligned
pulleys lead to excessive belt wear vibration, noise
and power loss, see Figure 10.
Figure 10
Clockwise
Rotation
All Models
Counterclockwise
Airflow