199
BELT DRIVE PLENUM FANS
Start-up procedures for plenum fans are similar to those for airfoil
or forward-curved fans described in the preceding section. Also
refer to the fan manufacturer’s Installation, Operation, and Main
-
tenance instructions shipped with the plenum fan section for fur
-
ther details.
DIRECT DRIVE PLENUM FANS
Start-up procedures are similar to those for fans described above
with the following additions:
1. Check tightness of bolts securing fan motor to base.
2. Check tightness of fan wheel bushing bolts (see Fig. 178) per
Table 44 below.
Table 44 —
Bushing Bolt Torque
3. Visually verify the radial clearance between the fan wheel
and the inlet cone is equal in all directions.
4. Verify the fan wheel to inlet cone overlap (see Fig. 178) is
within limits per Table 45 below.
5. Turn the fan wheel by hand to ensure no contact with inlet
cone.
6. If provided with piezometer ring, verify all tubing connec
-
tions are secure.
Table 45 —
Inlet Cone Overlap
7. Ensure VFD has been programmed with the correct maxi
-
mum fan speed and maximum output frequency to limit mo
-
tor speed (rpm) to fan maximum speed (rpm).
a. See label on fan sled for maximum fan speed (rpm).
b. Check VFD for maximum fan speed (parameter 2002) to
ensure that the fan maximum speed is the VFD maxi
-
mum speed.
c. Using the Parameters Mode (page 153) on the VFD, ver
-
ify that parameter 2002 has been changed to the value
shown on the fan label. If it does not match, DO NOT
start the unit. Press Edit (Soft Key 2) to enter correct
value for parameter 2002. Press Exit (Soft Key 1).
d. See motor nameplate for operating frequency (Hz) and
speed (rpm).
DRIVE PULLEY
NOMINAL
SCREW SIZE
TORQUE
(in.-lb)
NO. 6
9
NO. 8
16
NO. 10
30
1
/
4
70
5
/
16
140
3
/
8
216
Fig. 176 — Fan, Shaft and Bearing Details —
Roller — Extended Race, One or Both Sides
Fig. 177 — Fan, Shaft and Bearing Details —
Squeeze-Type Locking Collar
TORQUE TABLE
BEARING HOLDDOWN BOLT TORQUE
CAPSCREW AND
SETSCREW
SIZE (NO./in.)
HEX HEAD
ACROSS
FLATS (in.)
SQUARE HD
ACROSS
FLATS (in.)
TORQUE
10
3
/
32
—
25 in.-lb
1
/
4
1
/
8
—
60 in.-lb
5
/
16
5
/
32
—
10 ft-lb
3
/
8
3
/
16
—
17 ft-lb
7
/
16
7
/
32
—
25 ft-lb
1
/
2
1
/
4
1
/
2
40 ft-lb
5
/
8
5
/
16
—
90 ft-lb
3
/
4
3
/
8
—
125 ft-lb
BOLT SIZE (in.)
TORQUE (ft-lb)
3
/
8
- 16
30
1
/
2
- 13
63
5
/
8
- 11
100
3
/
4
- 10
165
BUSHING TYPE
TORQUE (in.-lb)
JA
72
SD
108
SK
180
SF
360
WHEEL SIZE
WHEEL - CONE OVERLAP (in.)
105
0.12 - 0.29
122
0.12 - 0.32
135
0.12 - 0.34
150
0.19 - 0.41
165
0.25 - 0.47
182
0.31 - 0.50
200
0.38 - 0.57
222
0.44 - 0.63
245
0.50 - 0.69
270
0.56 - 0.76
300
0.62 - 0.88
330
0.75 - 0.96
365
0.81 - 1.13
402
0.88 - 1.26
