The basic principle.
Door locking, movement permissions, braking, overspeed protection and end-of-travel provisions serve different purposes. They form a system rather than one all-purpose safety device.
Some functions prevent a start, some interrupt or control motion, and others act mechanically under defined conditions. Their boundaries and interactions depend on the installation design.
A missing door-lock condition.
Normal travel is inhibited because a required condition is absent. This is different from a governor triggering safety gear in response to excessive speed.
Follow the relationship.
- PreventEstablish required conditions before action.
- MonitorDetect relevant changes during operation.
- RespondApply the designed protective action.
Connect it to the lift.
Unintended Car Movement Protection addresses unintended car movement under specified conditions and is not interchangeable with every overspeed function. Maintenance, examination and testing provide different forms of assurance about these systems.
A closer look
This overview explains roles, not a compliance checklist. The applicable design and examination requirements must be assessed for the individual installation.
Check your understanding
Does one healthy safety indication prove that every protective function is healthy?
Reveal the explanation
No. Each function has its own scope, components and evidence requirements.