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Pulley Diameters Speeds

Reference data and engineering information about pulley diameters speeds for mechanics applications.

pulleydiametersspeeds

Overview

Engineering reference data for Pulley Diameters Speeds in mechanics.

Key Formulas

Newton's Second Law

F=maF = ma

Force = mass × acceleration.

Work

W=FdcosθW = Fd\cos\theta

Work = force × displacement × cos(angle).

Kinetic Energy

Ek=12mv2E_k = \frac{1}{2}mv^2

Energy of motion.

Potential Energy

Ep=mghE_p = mgh

Gravitational potential energy.

Variables

SymbolDescriptionUnit
FFForceN
mmMasskg
aaAccelerationm/s²
vvVelocitym/s

Multiple Belt Transmission System

For systems with three or more shafts, the speed relationships extend beyond single-belt transmissions. In a system with three shafts and four pulleys, the speed of the second shaft matches the speed of the third shaft due to direct coupling:

n_2 = n_3 \tag{6}

The overall speed ratio is determined by the product of the driving pulleys divided by the product of the driven pulleys, giving the speed of the fourth shaft:

n_4 = \frac{n_1 \cdot d_1 \cdot d_3}{d_2 \cdot d_4} \tag{7}

where all diameters must be in consistent units (e.g., mm or inches).

Example Calculation:

Using the parameters for a multiple belt transmission system:

  • n1=1000n_1 = 1000 rpm
  • d1=100d_1 = 100 mm
  • d2=50d_2 = 50 mm
  • d3=110d_3 = 110 mm
  • d4=60d_4 = 60 mm

The calculated speed of shaft 4 is: n4=10001001105060=3667 rpmn_4 = \frac{1000 \cdot 100 \cdot 110}{50 \cdot 60} = 3667 \text{ rpm}

6 rows
Input parameters and calculated result for multiple belt transmission example
Parameter
Value
Unit
n11000rpm
d1100mm
d250mm
d3110mm
d460mm
n4 (calculated)3667rpm

Source: engineeringtoolbox.com

References