3
SQN IO&M
B51141-004
SQI-D 70–90
FSC
SQN-D
FAN*
WHITE
BLACK
FSC
*
Black (High)
Blue (Medium)
Red (Low)
Line
White
Line
NOTE: Insulate unused leads separately; leads are located at the
motor inside the unit.
*
*
*See SQN Wiring Diagram
for correct lead.
Installation
Motor Installation
To prevent damage to the fan during shipping, motors 3
HP and larger, and extremely heavy motors (cast iron or
severe duty) are shipped loose and must be field mounted.
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 ca-
pacity of wires) is in accordance with the motor nameplate.
Refer to the
Wiring Diagrams
section.
Follow the wiring diagram in the disconnect switch
and the wiring diagram provided with the motor.
Correctly 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).
Direct Drive
Wire the electrical box on the blower housing.
Belt Drive
The motor can be wired directly since the motor is exter-
nal to the fan.
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.
Belt and Pulley Installation
If your fan is a direct drive, proceed to
Blower 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 ef-
ficiency and possible damage can occur.
1 foot
1/4 inch
Figure 1
Do not change the pulley pitch diameter to change ten-
sion. This will result in a different fan speed.
1. Loosen motor plate adjustment nuts on L-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.
2. 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 firm
-
ly pressing the belt. Refer to
Figure 1
.
3. Lock the motor plate adjustment nuts in place.
4. Ensure pulleys are properly aligned.
OFFSET
ANGULAR
OFFSET/ANGULAR
A
W
X
Y
Z
B
CENTER
DISTANCE
(CD)
GAP
GAP
Tolerance
Center Distance
Maximum Gap
Up thru 12”
1/16”
12” up through 48
1/8”
Over 48”
1/4”
Pulley Alignment
Pulley alignment is adjusted by
loosening the motor pulley set-
screw and by moving the motor
pulley on the motor shaft.
Figure 2
indicates where to mea-
sure 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.
Figure 3
illustrates using a carpenter’s square to ad-
just the position of the motor pulley until the belt is parallel
to the longer leg of the square.
Figure 2
Figure 3
