Elevator Stalling Detection via Load Weighing Sensors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing elevator control systems face challenges in detecting stalling conditions of the elevator car and counterweight efficiently, particularly in systems with varying suspension ratios and during overload situations.
Innovation Solution
The method employs Load Weighing Device (LWD) sensors to measure the total masses acting on the bedplate of the hoisting machinery, allowing for the detection of stalling conditions by determining the axial hanging masses on both sides of the traction sheave, without the need for additional switches or systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate switches or rope tension weight switch systems are used for stalling detection, then stalling detection capability is improved, but device complexity increases
Solution Approach 1:
The LWD sensors are designed to perform multiple functions: overload detection, drive starting torque setting, and stalling detection. By making the sensing system universal, the patent eliminates the need for separate stalling detection switches while maintaining reliable stalling detection capability through the same sensor infrastructure already present in the elevator system.
2Device complexity
If LWD sensors are used for stalling detection, then device complexity is reduced, but measurement precision requirements increase
Solution Approach 1:
The controller continuously monitors the output signals from the LWD sensors and compares them against expected operational ranges. This feedback mechanism enables the system to detect stalling conditions by identifying abnormal mass readings, thereby maintaining measurement precision through active monitoring and comparison rather than relying solely on raw sensor accuracy.
3Reliability
If continuous mass measurement is implemented, then stalling detection reliability is improved, but energy consumption increases
Solution Approach 1:
Instead of truly continuous measurement, the system implements periodic mass measurements at critical moments: during door operations, before drive startup, and during deceleration phases. This periodic sampling approach maintains stalling detection reliability by checking at key operational points while significantly reducing energy consumption compared to uninterrupted continuous monitoring.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables reliable detection of stalling conditions in elevators with any suspension ratio, including during overload situations, by utilizing existing sensors for overload detection and drive starting torque setting, thus improving operational safety and efficiency.
Implementation Method 1
LWD sensors positioned in connection with the bedplate of the hoisting machinery may measure the total masses acting on the bedplate
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The method comprises loading and/or unloading the car (10), determining whether the car doors are fully closed or not fully open, measuring a total actual axial mass FΣact hanging from the traction sheave (33), determining a stalling limit total minimum axial mass FΣmin, checking reopening of the car doors, whereby if the car doors are reopened, then return to beginning, else, continue, permitting starting of elevator, comparing the total actual axial mass with the stalling limit total minimum axial mass, whereby if the total actual axial mass is equal to or greater than the stalling limit total minimum axial mass, then permit normal run of the elevator car (10) to the next landing, else, stop the elevator.