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Poly-V
®
Belts
Installation Guide
1. Inspect sheaves
The following sections outline installation procedures that will
ensure maximum life and performance for your Poly-V® belts.
Check sheaves for cleanliness, damage and wear whether you
are replacing an existing belt, performing routine maintenance
or installing a new drive.
Minimum sheave diameter
If the sheave driver is a standard electric motor, refer to
Table 13 to be sure that the sheave diameter selected will meet
the National Electrical Manufacturers Association Standard for
minimum sheave diameters for electric motors. If the motor
sheave is smaller than the minimum diameter shown in this
table, increase the sheave diameter so that the motor sheave
will conform with the chart unless either an oversize or
outboard bearing is installed.
Perform further inspection if possible. Use Table 14 (on page
26) to determine if excessive wear has occurred or to select
replacement belts and sprocket cross sections.
a
S e
S g
Pitch
Diameter
Outside
Diameter
ୋ
d B
r t
r b
h g
Diameter
Over Balls
WARNING
Disconnect power supply to the machine before removing
or installing sheaves or belts.
WARNING
Do not reinstall damaged or worn sheaves on equipment.
Table 13 Small Sheave Diameters for Electric Motors
For example, if you are installing a 220J8, the minimum
allowance below center distance is 1/2 in. If you are
working to maintain tension, the minimum allowance above
center distance for belt take-up is also 1/2 in.
Motor
Nameplate
Horsepower
Standard Motor RPM
3450 1750 1160 870 675 575
Small Sheave Diameters (in.)
.12 or less
1.25 1.50 1.50
.25
1.25 1.25 1.50
.33
1.50 1.50 2.00
.50
2.00 2.00 2.50
.75
2.25 2.25 2.50 3.00 3.00 3.00
1
2.25 2.25 2.50 3.00 3.00 3.00
1.5
2.25 2.50 2.50 3.00 3.00 3.00
2
2.50 2.50 2.50 3.00 3.00 3.75
3
2.50 2.50 3.00 3.00 3.75 4.50
5
2.50 3.00 3.00 3.75 4.50 4.50
7.5
3.00 3.00 3.75 4.50 4.50 5.25
10
3.00 3.75 4.50 4.50 5.25 6.00
15
3.75 4.50 4.50 5.25 6.00 6.75
20
4.50 4.50 5.25 6.00 6.75 8.25
25
4.50 4.50 6.00 6.75 8.25 9.00
30
5.25 6.75 6.75 9.00 10.00
40
6.00 6.75 8.25 10.00 10.00
50
7.00 8.38 9.00 10.00 11.00
60
7.63 9.00 10.00 11.00 12.00
75
9.00 10.00 10.00 13.00 14.00
100
10.00 13.00 13.00 15.00 18.00
125
11.00 13.00 15.00 18.00 20.00
150
13.00 18.00 20.00 22.00
200
22.00 22.00 22.00
250
22.00 22.00
300
27.00 27.00
Banded Belts
Installation Guide
25