Narrow V-Belts Table 6. Arc of Contact Correction Factors Machinery's Handbook, 31st Edition
2574
Arc of Contact, θ , on Small Sheave (deg)
Arc of Contact, θ , on Small Sheave (deg)
C D d e e −
C D d e e −
Correction Factor
Correction Factor
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70
180 174 169 163 157 151 145 139
1.00 0.99 0.97 0.96 0.94 0.93 0.91 0.89
0.80 0.90 1.00 1.10 1.20 1.30 1.40 1.50
133 127 120 113 106
0.87 0.85 0.82 0.80 0.77 0.73 0.70 0.65
99 91 83
Table 7. Length Correction Factors
Cross Section
Cross Section
Standard Length Designation
Standard Length Designation
3V 5V 8V
3V 5V 8V
250 265 280 300 315 335 355 375 400 425 450 475 500 530 560 600 630 670 710 750 800 850 900 950
0.83 0.84 0.85 0.86 0.87 0.88 0.89 0.90 0.92 0.93 0.94 0.95 0.96 0.97 0.98 0.99 1.00 1.01 1.02 1.03 1.04 1.06 1.07 1.08 1.09 1.10 1.11
1180 1250 1320 1400 1500 1600 1700 1800 1900 2000 2120 2240 2360 2500 2650 2800 3000 3150 3350 3550 3750 4000 4250 4500 4750 5000
1.12 1.13 1.14 1.15
0.99 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17
0.89 0.90 0.91 0.92 0.93 0.94 0.94 0.95 0.96 0.97 0.98 0.98 0.99 1.00 1.01 1.02 1.03 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.09 1.10
0.85 0.86 0.87 0.88 0.89 0.90 0.91 0.92 0.93 0.94 0.95 0.96 0.96 0.97 0.98
1000 1060 1120
0.87 0.88 0.88
…
…
Number of Belts: The number of belts required for an application is obtained by dividing the design horsepower by the corrected horsepower rating for one belt. Classical V-Belts ANSI/RMA IP-20.— Classical V-belts are most commonly used in heavy-duty applications and include these standard cross sections: A, AX, B, BX, C, CX, D, and DX (Fig. 3, page 2578). Top widths range from 1 ⁄ 2 to 1 1 ⁄ 4 in. and are specified by cross section and nominal length. Classical belts can be teamed in multiples of two or more. These multiple drives can transmit up to several hundred horsepower continuously and absorb reasonable shock loads. Belt Cross Sections: Nominal dimensions of the four cross sections are given in Fig. 3. Belt Size Designation: Classical V-belt sizes are identified by a standard belt number consisting of a letter-numeral combination. The letter identifies the cross section; the numeral identifies the length as shown in Table 8. For example, A60 indicates an A cross section and a standard length designation of 60. An X following the section letter designa tion indicates a molded notch cross section, for example, AX60.
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