Elevator Hoisting Torque Control for Winding Prevention
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Solution Overview
Problem
In elevators with increased lifting height, the second elevating body can be wound by the hoisting machine when the movement of the first elevating body is limited, leading to potential damage due to excessive torque generation.
Innovation Solution
A control device with a first control unit to manage the hoisting machine and a second control unit to limit the generated torque below abnormal levels, preventing the winding of the second elevating body when the movement of the first is restricted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the traction capacity is increased as lifting height increases, then the elevator can handle higher floors, but the second elevating body may be wound by the hoisting machine when the first elevating body's movement is limited
Solution Approach 1:
The control device performs preliminary action by detecting abnormal torque generation in advance and limiting the torque before the second elevating body can be wound. The system monitors torque values and compares them against predetermined thresholds, taking preventive action by limiting torque output before the dangerous winding condition occurs.
Solution Approach 2:
The control device implements feedback by continuously monitoring the torque generated by the hoisting machine and comparing it with predetermined threshold values. Based on this feedback, the control device automatically adjusts the torque output to maintain it below dangerous levels, creating a closed-loop control system that prevents the winding of the second elevating body.
2Reliability
If torque limitation is implemented to prevent winding, then safety is improved, but the hoisting machine cannot generate sufficient torque for normal operation at high lifting heights
Solution Approach 1:
The control device applies dynamics by making the torque limitation adjustable and adaptive. Rather than using a fixed torque limit, the system can adjust the predetermined threshold values based on operating conditions, allowing the hoisting machine to generate sufficient torque for normal operation while dynamically preventing torque levels that would cause winding of the second elevating body.
Data Source
AI summary
Provided is a control device for an elevator including: a first control unit configured to control a hoisting machine configured to raise and lower a car and a counterweight in a hoistway; and a second control unit configured to obtain a generation torque which is a torque to be generated by the hoisting machine, and to limit the obtained generation torque to be generated by the hoisting machine so that the obtained generation torque is lower than an abnormal torque which is the generation torque generated when, under a state in which a movement of one of elevating bodies which are the car and the counterweight is limited, the other elevating body is wound by the hoisting machine.