System and method of detecting a dragging brake in an elevator application
US12404147B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 17, 2021 |
| Grant date | Sep 2, 2025 |
| Priority date | — |
| Expiry date | Jul 4, 2044 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB66B5/0037
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
A system and method for detecting a brake dragging during normal operation of a motor monitors torque at zero speed and at constant speed. For an inertial system acted upon by gravity, a value of torque required to maintain zero speed is approximately the same as a value of torque required to maintain operation at a constant speed. In an exemplary, elevator system, a motor drive determines the torque required to maintain zero speed operation of an elevator cab after a holding brake opens and before it begins controlling the motor to rotate. The motor drive again determines the torque required to maintain a constant speed and compares this value to the value of torque required to maintain zero speed. If the difference between the two values of torque is greater than a predefined threshold, then the motor drive determines that the brake is dragging and sets an error message.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.