Q. Write different relations used in belt drive.

Sol: Let:

D₁ = Diameter of driver

N₁ = Speed of the driver in Rotation per minute

D₂ = Diameter of the driven or Follower

N₂ = Speed of the driven or follower in Rotation per minute 
R₁ = Radius of the driver

R₂ = Radius of the driven or Follower

t = Belt thickness

X = Distance between the centers of two pulleys

α  = Angle of lap (less than 10º)

θ = Angle of contact (greater than 150º) (express in radian.)

μ = Coefficient of friction

s = Total slip in percentage
L = Total length of belt

Formula For                                                    Open Belt Drive

V.R.                                                          V.R = N2/N1

The thickness is                                    V.R = N2/N1  = 

The slip is                                             V.R = N /N   = (D1/D2) [1-s/100]

Slip and thickness both are   considered     V.R = N2/N1  =  [1-s/100]

Angle of contact                                    θ = ∏ - 2α

Angle of lap                                          Sinα = (r1-r2)/X

Length of belt                                       L = ∏ (r1  + r2)²/x + 2X