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Belt Length& Loading Calculator

Pulley centres for the purpose of calculating the belt length needed.

Diameter driver pulley D1 mm *[needed]
Diameter driven pulley D2 mm *[needed]
Center to center distance mm *[needed]
Transmitting power P kW *[optional]
Rotational speed driver pulley n1 rpm *[optional]
Pulley groove angle ° deg *[optional]
Coefficient of friction μ -*[optional]
Belt Datum Length L m Length
Use the Correction Factor for your Belt Type as below.
Z Section - Minus 22mm to give the inside length.
A Section - Minus 30mm to give inside length.
B Section - Minus 43mm to give inside length.
C Section - Minus 52mm to give inside length.
AX Section - Minus 30mm to give inside length.
BX Section - Minus 43mm to give inside length.
Drive ratio i = D1/D2 - to one RPM
Rotational speed driven pulley i1 n1 rpm
Belt speed v = p D1 n1 m/s
Smallest belt wrap angle a deg
Drive torque P/(2p n1) Nm
Drive force T1-T2 = P/v N
Effective friction coefficient μ = μ/(sin(*°/2)) -
Ratio of belt forces T1/T2 = exp(μ a) -
Belt tension load T1 = (T1-T2)/(1-T2/T1) N
Belt tension load T2 = T1 T2/T1 N
Shaft load Fa N


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