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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 = dp rk [ 1.004 - 1.652 / dp - 1.5747 x 10-4 ( dp r )2 - 0.2126 log( dp r ) ] + 1.652 r ( 1 - 1 / KSR )

V-Belt Cross Section "AX"

HP = dp rk [ 1.462 - 2.239 / dp - 2.198 x 10-4 ( dp r )2 - 0.4238 log( dp r ) ] + 2.239 r ( 1 - 1 / KSR )

V-Belt Cross Section "B"

HP = dp rk [ 1.769 - 4.372 / dp - 3.081 x 10-4 ( dp r )2 - 0.3658 log( dp r ) ] + 4.372 r ( 1 - 1 / KSR )

V-Belt Cross Section "BX"

HP = dp rk [ 2.051 - 3.532 / dp - 3.097 x 10-4 ( dp r )2 - 0.5735 log( dp r ) ] + 3.532 r ( 1 - 1 / KSR )

V-Belt Cross Section "C"

HP = dp rk [ 3.325 - 12.07 / dp - 5.828 x 10-4 ( dp r )2 - 0.6886 log( dp r ) ] + 12.07 r ( 1 - 1 / KSR )

V-Belt Cross Section "CX"

HP = dp rk [ 3.272 - 6.655 / dp - 5.298 x 10-4 ( dp r )2 - 0.8637 log( dp r ) ] + 6.655 r ( 1 - 1 / KSR )

V-Belt Cross Section "D"

HP = dp rk [ 7.160 - 43.21 / dp - 1.384 x 10-4 ( dp r )2 - 1.454 log( dp r ) ] + 43.21 r ( 1 - 1 / KSR )

Where:

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

Speed Ratio Range = Dp / dp

Where:

Dp = Pitch of Large Sheave
dp = 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:

References:

ANSI / RMA IP-24