COOK AVA - Manual (Page 3)

3
Discharge Duct Turns
When possible, allow 3 duct diameters between duct
turns or elbows and the fan outlet. Refer to the drawings at
the top of page 3.
Belt and Pulley Installation
Belt tension is determined by the sound the belts make
when the fan is first started. Belts will produce a loud
squeal which dissipates after the fan is operating at full
capacity. If the belt tension is too tight or too loose, lost effi-
ciency and possible damage can occur.
Do not change the pulley pitch diameter to change ten-
sion. This will result in a different fan speed.
a. Loosen motor plate adjustment bolts and move motor
plate in order that the belts can easily slip into the
grooves on the pulleys. Never pry, roll, or force the
belts over the rim of the pulley.
b. Adjust the motor plate until proper tension is reached.
For proper tension, a deflection of approximately 1/4”
per foot of center distance should be obtained by
firmly pressing the belt. Refer to Figure 3.
c. Lock the motor plate adjustment nuts in place.
d. Ensure pulleys are properly aligned. Refer to Figure 4.
Discharge Duct Turns
Correct
Incorrect
MIN
3 DIA
Air Flow
Small
Duct
Diverging
Inlet
Cone
Fan
Large
Duct
Air Flow
Small
Duct Inlet
Fan
Large
Duct
Correct Incorrect
Inlet Cone
1 foot
1/4 inch
Figure 3
Pulley Alignment
Pulley alignment is
adjusted by loosening
the motor pulley set-
screw and by moving
the motor pulley on the motor shaft.
Figure 4 indicates where to measure
the allowable gap for the drive alignment
tolerance. All contact points (indicated by
WXYZ) are to have a gap less than the
tolerance shown in the table. When the
pulleys are not the same width, the
allowable gap must be adjusted by half
of the difference in width (As shown in A
& B of Figure 4). Figure 5 illustrates
using a carpenter’s square to adjust the
position of the motor pulley until the belt
is parallel to the longer leg of the square.
Wiring Installation
All wiring should be in accordance with local ordinances
and the National Electrical Code, NFPA 70. Ensure the
power supply (voltage, frequency, and current carrying
capacity of wires) is in accordance with the motor name-
plate.
Lock off all power sources before unit is wired to power
source.
Leave enough slack in the wiring to allow for motor move-
ment when adjusting belt tension. Some fractional motors
have to be removed in order to make the connection with
the terminal box at the end of the motor. To remove motor,
remove bolts securing motor base to power assembly. Do
not remove motor mounting bolts.
Follow the wiring diagram in the disconnect switch
and the wiring diagram provided with the motor. Cor-
rectly label the circuit on the main power box and
always identify a closed switch to promote safety (i.e.,
red tape over a closed switch).
Figure 5
Tolerance
Center Distance
Maximum
Gap
Up thru 12” 1/16”
12” up through 48 1/8”
Over 48” 1/4”
OFFSET ANGULAR OFFSET/ANGULAR
A
W
X
Y
Z B
CENTER
DISTANCE
(CD)
GAP GAP
Figure 4