Elevator Balance Coefficient Detection Using Motor Power and Car Speed
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Solution Overview
Problem
Existing elevator balance coefficient detection methods are time-consuming, inaccurate, and inconvenient for on-site installation, particularly due to the reliance on force detection devices and differing transmission efficiencies between upward and downward movements.
Innovation Solution
A method and device that measure and record real-time car speed and motor power data during simultaneous horizontal movement of the car and counterweight, using electrical energy and speed detection devices to calculate the balance coefficient, accounting for transmission efficiency and adhering to standards like GB/T10059-2009 and TSG T7001-2009.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the traditional current-load curve method is used to detect balance coefficient, then the detection result is reliable and conforms to standards, but the detection time is excessively long (over 1 hour, one-third of total inspection time)
Solution Approach 1:
The patent replaces the traditional mechanical method of adding physical weights to the elevator car with an electrical field-based detection method. The system uses the elevator's existing motor and control system to apply electrical forces that simulate different load conditions, eliminating the need for physical test weights and repeated mechanical loading/unloading operations. This substitution dramatically reduces detection time while maintaining reliability by using electrical measurements rather than mechanical procedures.
Solution Approach 2:
The patent creates an electrical copy or simulation of the load conditions instead of using actual physical loads. By using the motor's electrical characteristics and control system to replicate the effects of different weights, the system can detect the balance coefficient without physically loading the elevator multiple times. This copying approach preserves the reliability of traditional methods while eliminating the time-consuming mechanical operations.
2Ease of operation
If free-loaded detection methods using force detection devices are used, then the detection process is simplified and no load is required, but the on-site installation is inconvenient and the detection accuracy differs from dynamic detection results
Solution Approach 1:
The patent makes the elevator's existing motor and control system serve multiple functions: it acts as both the drive mechanism for normal operation and as the detection mechanism for balance coefficient measurement. The control system can operate in different modes (normal drive mode and detection mode) without requiring separate specialized equipment. This multi-functionality maintains detection accuracy consistent with dynamic detection while simplifying the operation and eliminating the need for separate force detection devices.
Solution Approach 2:
The elevator system detects its own balance coefficient using its existing components (motor, control system, sensors) without requiring external force detection devices or specialized equipment. The system performs self-diagnosis by utilizing its own operational characteristics and electrical parameters. This self-service approach ensures measurement precision consistent with dynamic detection while greatly simplifying on-site installation and operation.
3Device complexity
If motor torque detection function of inverter is used to measure torque, then the detection process is simplified, but the detection accuracy cannot meet the requirements of GB/T10059-2009
Solution Approach 1:
The patent introduces an intermediary measurement approach that uses electrical parameters (current, voltage, power) as mediators to indirectly and more accurately determine motor torque and balance coefficient. Instead of relying directly on the inverter's torque detection function, the system uses electrical measurements combined with mathematical calculations to achieve higher accuracy. This intermediary method meets GB/T10059-2009 requirements while keeping the device complexity low by utilizing existing electrical sensors and processing capabilities.
Data Source
AI summary
An elevator balance coefficient detection method includes the following steps: (1) connecting an electrical energy detection device to a power line of an elevator driving motor, and connecting a speed detection device to a mechanical transmission member of an elevator car; (2) measuring and recording in real time the car speed data and driving motor power data when the car and a counterweight move to a same horizontal location; and (3) based on above detection data and basic parameters of the elevator to be tested, and according to transmission relationship between the elevator's operating condition and energy during operation, calculating and obtaining the value of the balance coefficient. A corresponding device includes an elevator data acquiring system and a detection data processing system. The elevator electrical energy detection device is an AC broadband power measuring device. The elevator speed measuring device is a steel rope displacement measuring device employing a photoelectric mouse chip circuit component or a tachometer type speed measuring device. The invention has the advantages of quick measuring and high accuracy of measuring.