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V-Belt Classical Speed to Horsepower Formulas and Calculator for Cross Sections

Belt Drive Design and Engineering
Mechanical Gear Design and Engineering

V-Belt Classical Speed to Horsepower Ratings Formulas and Calculator for Cross Sections

Cross Section Design Selection: Use the chart given below to determine if the V-belt cross section for any combination of design horsepower and speed of the faster shaft. When the intersection of the design horsepower and speed of the faster shaft falls near a line between two areas on the chart, the possibilities in both areas should be investigated. Special circumstances (such as space limitations) may lead to a choice of belt cross section different from that indicated in the chart.

Design HP = Basic Horsepower Rating x Service Factor

Basic Horsepower Rating Formulas

V-Belt Cross Section "A"

HP = d_p r_k [ 1.004 - 1.652 / d_p - 1.5747 x 10^-4 ( d_p r )² - 0.2126 log( d_p r ) ] + 1.652 r ( 1 - 1 / K_SR )

V-Belt Cross Section "AX"

HP = d_p r_k [ 1.462 - 2.239 / d_p - 2.198 x 10^-4 ( d_p r )² - 0.4238 log( d_p r ) ] + 2.239 r ( 1 - 1 / K_SR )

V-Belt Cross Section "B"

HP = d_p r_k [ 1.769 - 4.372 / d_p - 3.081 x 10^-4 ( d_p r )² - 0.3658 log( d_p r ) ] + 4.372 r ( 1 - 1 / K_SR )

V-Belt Cross Section "BX"

HP = d_p r_k [ 2.051 - 3.532 / d_p - 3.097 x 10^-4 ( d_p r )² - 0.5735 log( d_p r ) ] + 3.532 r ( 1 - 1 / K_SR )

V-Belt Cross Section "C"

HP = d_p r_k [ 3.325 - 12.07 / d_p - 5.828 x 10^-4 ( d_p r )² - 0.6886 log( d_p r ) ] + 12.07 r ( 1 - 1 / K_SR )

V-Belt Cross Section "CX"

HP = d_p r_k [ 3.272 - 6.655 / d_p - 5.298 x 10^-4 ( d_p r )² - 0.8637 log( d_p r ) ] + 6.655 r ( 1 - 1 / K_SR )

V-Belt Cross Section "D"

HP = d_p r_k [ 7.160 - 43.21 / d_p - 1.384 x 10^-4 ( d_p r )² - 1.454 log( d_p r ) ] + 43.21 r ( 1 - 1 / K_SR )

Where:

dp = pitch diameter of small sheave, in.
r = rpm of the faster shaft.
r_k = r / 1000
K_SR = speed ratio factor given in the accompanying Table below.

Speed Ratio Range = D_p / d_p

Where:

D_p = Pitch of Large Sheave
d_p = Pitch of Small Sheave

Speed Ratio Range	KSR
1.00 - 1.01	1.0000
1.02 - 1.04	1.0112
1.05 - 1.07	1.0226
1.08 - 1.10	1.0344
1.11 - 1.14	1.0463
1.15 - 1.20	1.0586
1.21 - 1.27	1.0711
1.28 - 1.39	1.0840
1.40 - 1.64	1.0972
> 1.64	1.1106

 

FPM to RPM Equation:
r = s / ( π d )

RPM to FPM Equation:
s = r π d

Where:

r = rpm
s = ft / min
d = diameter of pulley in ft

Related:

• Synchronous Timing Belt Tooth Section Dimensions Table per ANSI / RMA IP-24
• Synchronous Timing Belt Pulley Dimensions Table per ANSI / RMA IP-24
• Synchronous Timing Belt Lengths and Tolerances per. ANSI RMA IP-24 Table
• Synchronous Timing Belt Pitches
• Service Factors Synchronous Timing Belts
• Synchronous Timing Belt Standard Widths and Tolerances Table
• Synchronous Belt Standard Pulley Diameters ANSI/RMA IP-24 Table
• Timing Belt Pulley Mechanical Tolerances per. ANSI RMA IP-24

References:

ANSI / RMA IP-24