Elevator roping diagram
The roping arrangement affects rope speed, rope tension, required rope length, traction geometry and the equivalent number of bends used in the ISO factor-of-safety calculation. The drawing tool below lays out a basic reeving arrangement and transfers the geometry into the RopeFactor calculator.
The arrangements
| Arrangement | Rope speed | Rope tension | Typical use |
|---|---|---|---|
| 1:1 | = car speed | Full load on the ropes | Low and mid rise, geared and gearless |
| 2:1 | 2 × car speed | Roughly half, shared over more falls | Higher rise, smaller machine, more rope |
| Basement / underslung | as above | as above | Machine at the bottom; the rope turns back up the hoistway |
| Double wrap | unchanged | unchanged | More traction from a second pass round the drive sheave |
Values affected by the roping arrangement
- Rope speed. Determines the minimum factor of safety taken from ASME A17.1 Table 2.20.3 — see the table.
- Equivalent bends. Traction and deflector sheaves affect Nequiv used in the ISO 8100-2 factor-of-safety calculation — see Formula (36).
- Rope length. Required rope length changes with machine location and roping ratio — see the four reeving formulas.
- Traction. Wrap angle and groove geometry affect the available traction.
Draw the arrangement
Move the sheaves, select the roping arrangement and enter the loads. The drawing is created locally in your browser and is not sent anywhere. Use Continue in the calculator to transfer the geometry and loads. A laptop or tablet is recommended for the drawing tool.
The interactive drawing board needs JavaScript. Everything above describes what each arrangement changes, and the calculator accepts the geometry directly.
Best on a laptop or a tablet — it is a drawing tool, and a phone screen is a tight fit for one.
See also
Elevator rope order length — the four reeving formulas ASME A17.1 minimum rope safety factor by speed ISO 8100-2 minimum rope safety factor A worked calculation example