Mechanical power transmission

Moving energy as motion or pressure through shafts, ropes, hydraulics and compressed air.

Transport · Heat, motion and embodied energy · No. 66

• Transport
• Form: Mechanical

Paris once ran about 1,000 km of compressed-air pipes to 10,000 customers, until the network was abandoned in 1995.

Chart: Illustration: Mechanical power transmission

Where it comes from

Chart: Map of where it comes from

Before electricity, factories moved power with spinning shafts and belts, and cities piped pressurised water or air to machines. Gears and belts still sit inside almost every motor-driven machine.

Three things to know

1. London's hydraulic mains, at about 55 bar, served about 8,000 machines in 1930 and now carry telecom cables.
2. A single compressed-air leak can cost USD 1,046 to 16,764 a year, depending on the size of the hole.
3. Alpine-region ropeways recorded 0.07 deaths per 100 million passengers in 2015-2022, against 0.18 for buses and trams.

The journey

1. 1 Prime moverEngine, motor or water wheel
2. 2 Gears and beltsPass torque and change speed
3. 3 Ropes or pipesHaul ropes, hydraulic or air mains
4. 4 End useRams, air tools, cabins and machines
5. 5 ExhaustSpent air vented, fluid returned

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