Belt Drives Chain Drives Gears μ=F/G T e =T 1 -T 2 T 1 :tight T 2 :slack P b = Bb 2 tan ∗ α / 2 P b =Pitch diameter variation B b =belt top thickness H b =belt thickness α=sheave groove angle V=rw = radius 2 π n 60 n=rpm of pulley Design HP=rated HP X service factor Corrected HP=HP per belt X “F” factor X number of belts Actual speed ratio= rpm 1 rpm 2 = D 2 D 1 (observation) Theoretical speed ratio= D 2 D 1 = r 2 r 1 D=diameter Overall TSR=TSR 1 x TSR 2 x TSR n Input HP= Torque x RPM 63000 lb-in HP= Torque x RPM 5252 lb-ft Torque= 63025 x HP N in-lb Torque Ratio= T 2 T 1 = N 1 N 2 (inverse of speed ratio) Overall ASR= D first /D last Theoretical velocity ratio= ¿ of teet hdriven ¿ of teet hdriver Actual velocity ratio= Driver speed drivenspeed L=2C + N + n 2 + ( N − n ) 2 4 πC C= L − N + n 2 + √ L − ( N + n ) 2 2 − 8 ( N − n ) 2 4 π 2 4 L=length of chain in pitches C=center distance in pitches N=number of teeth in large sprocket n=number of teeth in small sprocket Design HP= HP x SF L= # of links x pitch Mechanical Advantages: