The basic principle.

A traction machine combines the elements needed to turn a drive sheave. Depending on design, it includes a motor, gearing, bearings and a brake, or a gearless motor directly coupled to the sheave.

The sheave transfers force through traction at the suspension contact. It does not simply wind all the rope onto a drum. Rope tension, contact geometry and condition affect its ability to transmit force.

Motor speed is not car speed.

A worked-through example

A gearbox can reduce speed before the sheave; sheave diameter converts rotation to rope travel; roping ratio then relates rope travel to car movement.

Trace the machine and suspension.

Trace the suspension path

A simple one-to-one traction layoutA car rises while its counterweight descends. A continuous suspension path passes over the driven sheave. Separate guide rails constrain both to a vertical path; ropes do not wind onto a storage drum.Driven traction sheaveSuspensionCarCounterweightGuide rails
  1. Traction sheave: the machine turns the sheave. Contact between suspension and groove transfers force; the suspension passes over it rather than being stored on a drum.
  2. Car and counterweight: in this simple 1:1 example, one rises as the other descends by the same distance. Other roping arrangements introduce additional pulleys.
  3. Guide rails: guide the car and counterweight. They are separate from the suspension that carries the load.
  4. Machine: a motor supplies shaft torque directly or through gearing. The mechanical brake is a separate, coordinated part of the machine; it is omitted here to keep the suspension path visible.
Simplified 1:1 arrangement showing the car travelling upwards. One suspension line represents a set of ropes or belts. Motor, brake, doors, safety gear and position sensors are omitted; this is not a complete installation drawing.

Connect it to the lift.

The brake and drive perform coordinated but different duties. Noise or vibration may originate in the motor, bearings, gearing, sheave contact or supporting structure. Machine condition is assessed as an assembly.

A closer look

Machine-room-less describes equipment location rather than one universal motor or suspension design. Layout and machine type are separate characteristics.

Check your understanding

Does “gearless” mean there is no mechanical brake?

Reveal the explanation

No. Removing a gearbox does not remove the need for the installation’s braking functions.

Further reading.

Optional reading to explore this lesson in more detail.