Most modern lifts are traction lifts. These lifts have a system of ropes that are driven in the grooves of a driving sheave. The car is connected to one end of the ropes, while the counterweight is connected to the other one. The vertical movement of the car and counterweight, without rope slippage, is ensured by the availability of sufficient traction.
If there is not enough traction, the ropes will slip uncontrollably over the driving sheave, resulting in a dangerous situation. Therefore, the EN Code requires that there is sufficient traction available, in case of a possible extreme situation.
On the other side, in the event that the car or counterweight are stalled in the shaft for any reason, further movement of the car or counterweight can result in a dangerous situation. For that reason, in that situations, the EN Code requires that the available traction is limited and the ropes slip.
This gap between having enough traction and the need to lose traction is quite narrow. This is a key challenge that any elevator design engineer will have to face.
- To understand the concept of traction.
- To learn the definition and functioning of a traction lift, and the different types of grooves and their characteristics.
- To learn the concepts of applied and available traction.
- To understand how the weight of the car empty and other factors affect traction.
- To learn and understand the formulae given in EN 81 to evaluate the available traction.
Ronald D’Souza, Corporate Trainer at Schindler Management Ltd., Electrical Engineer with about 32 years of experience in the elevator industry, having worked in Installation and Maintenance Operations, Sales, Procurement and Technical Training. MBA from Webster University. Doctorate in Political Science from Vienna University with a Dissertation on EU Research and Technology Development Policy.
Personnel with a good basic knowledge of the functioning of a lift and at least an undergraduate level of mathematical knowledge.
8 videoconferences of 1,5 hours each.
Schedule and place
Schedule: Dates TBD (Wednesdays and Saturdays). The times will depend on the groups.
Place: Online, via Docensas Platform.
- Meaning and definition of traction.
- EN 81 Code requirements.
- Types of grooves and how they affect traction.
- Applied traction and available traction.
- What can be done to increase or decrease traction?
- Formulae given in EN 81 20/50 to evaluate traction.
- Case study.
- Review. Other topics requested by participants.
- Active class participation.
- Completion of a case study.