Equilibrium of moments on a differential pulley block (TM122)

Equilibrium of moments on a differential pulley block (TM122)

demonstration of power savings on the differential pulley block



  • The TM 122experimental unit illustrates the equilibrium conditions on a differential pulley block.
  • The relation between pulley diameter, lifting force and torque is demonstrated.
  • Three pulleys with different diameters are mounted on a shaft, which is itself mounted on ball bearings.
  • Weights can be hung on the cables.
  • The forces act on the one hand directly on the periphery of the pulley with the largest diameter and another force acts on the pulley with the smaller diameter via a loose roller.
  • Using weights, it is possible to vary these forces until equilibrium is reached.
  • The experimental unit is designed to be fixed to a wall.

Technical Details:


  1. investigation of the equilibrium of moments on a differential pulley block
  2. anodised aluminium pulleys
  3. 1 loose roller
  4. ball bearing-mounted steel shaft
  5. bracket for wall mounting

Technical Data:


  • Ø=250mm
  • Ø=100mm
  • Ø=50mm

Loose roller:

  • Ø=75mm


  • 2x 1N (hanger)
  • 4x 0,5N
  • 4x 1N
  • 4x 2N
  • 4x 5N

Base plate:

  • WxH: 300x250mm

Dimensions & Weight:

  • L x W x H: 300x280x250mm
  • Weight: approx. 14kg

Learning Objections/Experiments:

  • fundamentals of the equilibrium of moments: acting forces, generated moments and equilibrium
  • relation between power savings and cable route

Scope of Delivery:

  • 1 experimental unit
  • 1 set of weights
  • 2 cables
  • 1 set of instructional material

Due to the continuous development of our products, the goods supplied may vary in detail to that illustrated on this Website.