V-Belts are the very most common type of belt drive used for power transmission. Their important function is to transmit power from a one primary source, like an electric motor, to a secondary unit. They provide the excellent combination of traction, speed transfer, load distribution, and extended service life.

1. V-Belt Drive
Types & Design Procedure

2. 06-10-2021 2
Types of V-Belt
A Type B Type C Type D Type E Type

3. Ratio of Driving Tensions for V-Belt
𝑇1
𝑇2
= 𝑒𝜇𝑎/ sin 𝛽
𝑇1
𝑇2
= 𝑒𝜇𝑎 𝑐𝑜𝑠𝑒𝑐 𝛽
Where,
• T1 & T2 = Tensions in the tight and Slack Side Respectively
• 2β = Angle of the groove
• μ = Co efficient of Friction between the belt and sides of the groove
𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑏𝑒𝑙𝑡𝑠 =
𝑇𝑜𝑡𝑎𝑙 𝑝𝑜𝑤𝑒𝑟 𝑡𝑟𝑎𝑠𝑛𝑚𝑖𝑡𝑡𝑒𝑑
𝑃𝑜𝑤𝑒𝑟 𝑇𝑟𝑎𝑛𝑠𝑚𝑖𝑡𝑡𝑒𝑑 𝑝𝑒𝑟 𝑏𝑒𝑙𝑡
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4. Design of V-Grooved Pulley
B.Varun
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5. Materials of V-Grooved Pulleys
Materials of Sheves Characteristic s and its Applications
Cast Iron
Economical, Stable and Durable
Excellent Friction Characteristics
Pressed Steel
Lighter, Cheaper
Excessive belt slip, Wear and Noise
Formed Steel Used in Automotive and Agricultural purposes
Diecast Aluminium Special Applications
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6. Dimensions of Sheaves
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7. Dimensions of standard V-Grooved Pulley
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Type of
belt
W D A C F E
No of
Sheave
grooves
(n)
Groove
angle
(2β) in
degrees
A 11 12 3.3 8.7 10 15 6 32,34,38
B 14 15 4.2 10.8 12.5 19 9 32,34,38
C 19 20 5.7 14.3 17 25.5 14 34,36,38
D 27 28 8.1 19.9 24 37 14 34,36,38
E 32 33 9.6 23.4 29 44.5 20 -
PSG Data Book 7.70
𝑭𝒂𝒄𝒆 𝒘𝒊𝒅𝒕𝒉 (𝒍) = (𝒏 − 𝟏)𝒆 + 𝟐𝒇

8. Design Procedure
• Select the cross section of the belt (ie Type of belt) depending on
the power to be transmitted (PSG Data Book Pg No 7.58)
• For the selected cross section of the belt , select the various
required dimensions (PSG Data Book Pg No 7.70)
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9. Design of V-Belt
B.Varun
06-10-2021 9

10. Design
Using manufacturers data
Using Basic equations
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11. Design Procedure
Selection of belt
cross section
Selection of pulley
diameters
(D and d)
Selection of centre
distance (C)
Determination of
nominal pitch
length
Selection of various
modification
factors
Calculation of
maximum power
capacity
Determination of
number of belts
Calculation of
actual centre
distance
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12. Selection of Belt cross Section
• Select the cross section of the belt (ie Type of belt) depending on
the power to be transmitted (PSG Data Book Pg No 7.58)
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Cross Section
Symbol
Area
mm2
Usual load of
drive
kW
Recommende
d minimum
pulley pitch
dia (d)
mm
Nominal top
width (w)
mm
Nominal
Thickness (T)
mm
Mass per
metre (m)
kg/m
A 80 0.75-5 75 13 8 0.106
B 140 2-15 125 17 11 0.189
C 230 7.5-75 200 22 14 0.343
D 475 22-150 355 32 19 0.595
E 695 30-190 500 38 23 -

13. Selection of Pulley Diameter (d and D)
• Select small pulley diameter from table (PSG Data Book Pg No
7.58)
• Using Speed ratio find maximum diameter
• Round off to the nearest standard diameter
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14. Selection of Centre Distance
Select the centre distance (PSG Data Book Pg No 7.61)
𝐶𝑚𝑖𝑛 = 0.55 𝐷 + 𝑑 + 𝑇
𝐶𝑚𝑎𝑥 = 2 (𝐷 + 𝑑)
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15. Determination of Nominal Pitch length
𝑳 = 𝟐𝑪 +
𝝅
𝟐
𝑫 + 𝒅 +
(𝑫 − 𝒅)𝟐
𝟒𝑪
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For pitch length add with inside length
36 mm for A Belt
43 mm for B Belt
56 mm for C Belt
79 mm for D Belt
92 mm for E Belt

16. Selction of various modification factors
Length correction factor
(PSG Data Book Pg no = 7,.58,7.59,7.60)
Arc of contact correction factor
(PSG Data Book Pg no = 7.68)
Service factor
(PSG Data Book Pg no = 7.69)
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17. Calculation of Maximum power capacity
Maximum power capacity
(PSG Data Book Pg No 7.62)
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18. Determination of no of Belts
𝒏𝒃 =
𝑷 ∗ 𝑭𝒅
𝒌𝑾 ∗ 𝑭𝒄 ∗ 𝑭𝒅
PSG Data Book Pg no = 7.70
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19. Calculation of Actual Centre Distance
𝐶𝑎𝑐𝑡𝑢𝑎𝑙 = 𝐴 + 𝐴2 − 𝐵
𝐴 =
𝐿
4
− 𝜋
𝐷 + 𝑑
8
𝐵 =
(𝐷 − 𝑑)2
8
L=Nominal pitch length of the belt from table (Step 5)
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20. B.Varun
9787608011
bvarun.me@gmail.com
varun.me@srit.org
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