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+--- Thread: Solver: Length of a V Belt (/thread-12932.html)
Solver: Length of a V Belt - Eddie W. Shore - 05-06-2019 11:40 AM
Blog Entry: http://edspi31415.blogspot.com/2019/05/hp-prime-and-hp-42sdm42free42-length-of.html
The following equation relates the length of a V belt, the center to center distance between two pulleys or sheaves:
L = 2 * C + 1.57 * (D + d) + (D - d)^2/(4 * C)
where:
L = length of the V belt, the belt that wraps around two pulleys (or sheaves)
C = center to center distance
D = diameter of the large pulley/sheave
d = diameter of the small pulley/sheave
HP Program VBELT
This program creates four global variables:
beltlength = L
centerdist = C
lrgpulley = D
smpulley = d
The program then takes you to the Num page of the Solve app. This allows us to create descriptive variables to help us in the Solve app.
Global variables are created outside the main program.
Code:
// create global variables
// outside the main program
EXPORT beltlength;
EXPORT centerdist;
EXPORT lrgpulley;
EXPORT smpulley;
EXPORT VBELT()
BEGIN
// 2019-04-28 EWS
STARTAPP("Solve");
// uncheck E0-E9
LOCAL k;
FOR k FROM 0 TO 9 DO
Solve.UNCHECK(k);
END;
// enter equation to E1
E1:="beltlength=2*centerdist+
1.57*(lrgpulley+smpulley)+
(lrgpulley-smpulley)^2/
(4*centerdist)";
Solve.CHECK(1);
// go to Num View
STARTVIEW(2);
END;Example 1:
Large Pulley Diameter = 1 in
Small Pulley Diameter = 3/4 in
Center to Center Distance = 1.5 in
Result: V Belt Length ≈ 5.7579 in
Example 2:
Large Pulley Diameter = 1 in
Small Pulley Diameter = 7/16 in
V Belt Length = 6.24 in
Result: Center to Center Distance ≈ 1.975 in
Source:
Gladstone, John "Air Conditioning Testing and Balancing: A Field Practice Manual" Van Nostrand Reinhold Company: New York. 1974 ISBN 0-442-22703-5