Mechanical Advantage

Haul systems

Beta

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Haul T = 1 → load T = 3. Z-rig. Standing end at the load. Traveling pulley adds 2. The pulley at the anchor is a change of direction — friction, not advantage.

3:1 Simplesimple

Theoretical
3.0:1
Actual (est.)
2.70:1
Haul force
0.74 kN167 lbf
Haulers @ 45 lbf
4

Load

2.00 kN

Pulley efficiency

80% is a dirty bushing pulley. 85% is CMC’s teaching example. 90% is a typical side-plate pulley. 95% is a high-efficiency bearing sheave. AMA ≈ TMA × η^(moving pulleys).

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