Elevator Hoist Brake Testing Using Assisted Motor Torque
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Solution Overview
Problem
Existing methods for testing elevator hoisting machine brakes lack accuracy in assessing their braking torque across the entire operational range, particularly when one brake fails, necessitating enhanced testing methods to ensure safety margins.
Innovation Solution
A method involving a preselected test load, elevator balancing, and friction measurement is used to determine the required assisting motor torque, allowing for accurate testing of hoisting machine brakes by applying torque and measuring elevator car movement to detect operational anomalies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a simple brake test method is used (removing motor torque and checking for movement), then the testing process is simple, but the measurement precision of braking torque across the entire operational range is insufficient
Solution Approach 1:
The method performs preliminary measurements of friction and balancing before the actual brake test, and calculates the required test torque in advance based on these measurements and the desired test load. This preparation ensures that the subsequent brake testing can be conducted with high precision across the entire operational range, while maintaining operational simplicity through automated calculations.
Solution Approach 2:
The patent introduces an assisting motor torque as an intermediary element to achieve the desired test load. By carefully controlling the motor torque to complement the elevator unbalance and account for friction, the system can apply precise test loads to the brakes. This intermediary torque allows accurate measurement of braking performance without requiring complex direct measurement apparatus.
2Device complexity
If the test load is established only by elevator unbalance, then the testing setup is simple, but the reliability of brake testing is insufficient due to unidealities in real-life elevator systems
Solution Approach 1:
The method dynamically adjusts the test parameters by measuring actual friction and balancing conditions, then calculating the required assisting motor torque to achieve the desired test load. This parameter adjustment compensates for unidealities in real-life elevator systems, ensuring reliable brake testing while maintaining relatively simple test setup procedures through automated parameter optimization.
Solution Approach 2:
The system incorporates feedback mechanisms by measuring friction and balancing conditions during the test setup, then using this information to calculate and adjust the assisting motor torque. This feedback loop ensures that the test load accurately reflects real operating conditions, thereby improving testing reliability without significantly increasing setup complexity.
3Productivity
If multiple brakes are tested simultaneously, then the testing efficiency is high, but the measurement precision of individual brake performance is reduced
Solution Approach 1:
The testing method segments the brake testing process by evaluating individual brake units or specific brake combinations separately. By systematically testing different brake configurations (single brakes, pairs of brakes, etc.), the method maintains high productivity through structured testing sequences while ensuring precise measurement of individual brake performance and their interactions.
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
Enables precise evaluation of brake performance, ensuring safety margins are maintained even if one brake fails, by accurately determining the necessary torque and detecting any degraded brake conditions.
Implementation Method 1
a motor and a traction sheave connected to the motor for moving the elevator car and the counterweight via the elevator ropes
Implementation Method 2
at least two brakes, which are arranged to stop and prevent the elevator car from moving when the elevator is stopped
Implementation Method 3
obtaining information of elevator balancing B
Data Source
AI summary
A method for testing an elevator hoisting machine brake with a preselected test load TL includes confirming empty elevator car positioned at a test location stest; obtaining information of elevator balancing B; obtaining information of friction Fr of the elevator at the test location stest; determining required assisting test torque TM of a hoisting machine motor based on said test load TL, balancing B and friction Fr; opening one of the brakes while keeping rest of the brakes engaged in braking position, applying torque with the motor at most up to the required test torque TM, measuring movement of the elevator car, and if movement of the elevator car was detected, generating a signal indicating degraded condition of one or more hoisting machine brakes.