MEPX
Chapter 8 of 10All chapters
  1. 1The simple machines
  2. 2Levers and gears
  3. 3Engines
  4. 4Hydraulics and pneumatics
  5. 5Getting power where it is needed
  6. 6Household machines
  7. 7Electric motors and generators
  8. 8Efficiency and losses
  9. 9Why machines fail
  10. 10Working out an unfamiliar machine

Chapter 8 of 10

Efficiency and losses

Where the energy goes.

Nothing is free

Every stage loses energy as heat, sound and vibration. Adding stages multiplies those losses, which is why direct drive beats a chain of transmissions where it is practical.

  • Friction is the main loss, which is why lubrication matters so much.
  • A machine that runs hot is telling you where its losses are.

Rated against real

Ratings assume ideal conditions. Load, temperature, altitude and wear all reduce real output, which is why sizing uses the worst case rather than the label.