Abbreviations used in formulas
a=Transmission center distance (temporary) (mm)
anom=center distance calculated using standard belt length (mm)
bd=reference width (mm)
b1=top width (mm)
c1=Wrap angle arc correction coefficient (mm)
c2=Service factor (mm)
c3=belt length factor (mm)
c4=idler coefficient (mm)
ddg=reference diameter of large pulley (selected according to BS 3790/DIN 2211) (mm)
ddk=reference diameter of small pulley (selected according to BS 3790/DIN 2211) (mm)
dd1=reference diameter of driving pulley (mm)
dd2=reference diameter of driven pulley (mm)
E=belt deviation per 100mm span (mm)
Ea=belt deviation of a given span length (mm)
f=load used to set belt tension (N)
fB=Deflection ratio (s-1)
i=transmission ratio
k = constant used to calculate the centrifugal force in the group
L=span length (mm)
List=standard inner belt length (mm)
Lith=Calculated inner belt length (mm)
Last=standard length (mm)
Ldth=calculated belt reference length (mm)
ng=rotation speed of large pulley (min-1)
nk=speed of small pulley (min-1)
n1=speed of driving pulley (min-1)
n2=speed of driven pulley (min-1)
P=motor power or rated operating power (Kw*)
PB=Design power (Kw*)
PN=Rated power of each belt (Kw*)
Sa=minimum static shaft load (N)
T=Minimum static tension of each belt (N)
V=belt speed (m/s)
Ud=reference circumference
x=Minimum tolerance of belt stretch and wear exceeding the center distance aom (mm)
y=Minimum tolerance of belt installation lower than center distance aom (mm)
z = number of bands
α=angle belt of belt drive=90°-β/2 (°)
β=The wrap angle arc on the small pulley (°)