Abbreviations in belt design formulas

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 (°)