Typical Sheave Diameter And Deflection Force; Determine Fan Speed - Trane CSAA Installation, Operation And Maintenance Manual

Table 40. Typical sheave diameter and deflection force
Smallest sheave
Cross diameter range
section (in.)
3.0–3.6
A, AX 3.8–4.8
5.0–7.0
3.4–4.2
B, BX 4.4–5.6
5.8–8.6
7.0–9.0
C, CX
9.5–16.0
12.0–16.0
D
18.0–20.0
2.2–2.4
3V, 3VX 2.65–3.65
4.12–6.90
4.4–6.7
5V, 5VX
7.1–10.9
11.8–16.0
12.5–17.0
8V
18.0–22.4

Determine Fan Speed

WARNING
Live Electrical Components!
Failure to follow all safety precautions when exposed to
rotating components could result in death or serious
injury.During installation, testing, servicing and
troubleshooting of this product, it may be necessary to
measure the speed of rotating components. Have a
qualified licensed service individual who has been
properly trained in handling exposed rotating
components perform these tasks.
CLCH-SVX07K-EN
Super gripbelts and
unnotched gripbands
Speed (rpm)
range Used belt
1,000–2,500 3.70
2,501–4,000 2.80
1,000–2,500 4.50
2,501–4,000 3.80
1,000–2,500 5.40
2,501–4,000 4.70
860–2,500 n/a
2,501–4,000 n/a
860–2,500 5.30
2,501–4,000 4.50
860–2,500 6.30
2,501–4,000 6.00
500–1,740 11.50
1,741–3,000 9.40
500–1,740 14.10
1,741–3,000 12.50
200–850 24.90
851–1,500 21.20
200–850 30.40
851–1,500 25.60
1,000–2,500 n/a
2,501–4,000 n/a
1,000–2,500 3.60
2,501–4,000 3.00
1,000–2,500 4.90
2,501–4,000 4.40
500–1,749 n/a
1,750–3,000 n/a
3,001–4,000 n/a
500–1,749 12.70
1,750–3,000 11.20
500–1,749 15.50
1,750–3,000 14.60
200–850 33.00
851–1,500 26.80
200–850 39.60
851–1,500 35.30
Belt Deflection Force (lbs)
New belt
5.50
4.20
6.80
5.70
8.00
7.00
n/a
n/a
7.90
6.70
9.40
8.90
17.00
13.80
21.00
18.50
37.00
31.30
45.20
38.00
n/a
n/a
5.10
4.40
7.30
6.60
n/a
n/a
n/a
18.90
16.70
23.40
21.80
49.30
39.90
59.20
52.70
Fan speed can be determined using a strobe-type
tachometer, or revolution counter.
Check unit vibration if the fan speed is changed more than
five percent from the original designed speed, or if parts
such as shafts, fan wheels, bearings, or other drive
components are replaced. Do not exceed the maximum
fan speed.
Pay particular attention to any vibration, noise, or
overheating of the motor and fan bearings; however, note
that bearings may run warm during break in.
Start-Up
Gripnotch belts and
notched gripbands
Used belt New belt
4.10 6.40
3.40 5.00
5.00 7.40
4.30 6.40
5.70 9.40
5.10 7.60
4.90 7.20
4.20 6.20
7.10 10.50
7.10 9.10
8.50 12.60
7.30 10.90
14.70 21.80
11.90 17.50
15.90 23.50
14.60 21.60
n/a n/a
n/a n/a
n/a n/a
n/a n/a
3.30 4.90
2.90 4.30
4.20 6.20
3.80 5.60
5.30 7.90
4.90 7.30
10.20 15.20
8.80 13.20
5.60 8.50
14.80 22.10
13.70 20.10
17.10 25.50
16.80 25.00
n/a n/a
n/a n/a
n/a n/a
n/a n/a
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