Elevator Balancing Weight Difference via Motor Power Model

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Solution Overview

Problem

Existing methods for determining the balancing weight difference in elevator systems are laborious and costly, as they require manual weighing of elevator cars and counterweights, which often deviate from theoretical values due to modifications over time.

Innovation Solution

A simplified power model is used to calculate the balancing weight difference by measuring power parameters during a test run, disregarding components that are balanced or independent of travel direction, allowing for easy retrieval of the weight difference between the elevator car and counterweight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual weighing of elevator car and counterweight is performed, then accurate balancing weight difference is obtained, but labor effort and costs increase significantly

Engineering Contradiction:

Improvebalancing weight differenceVSAvoidlabor effort

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the mechanical weighing system with an electrical measurement system. Instead of physically weighing the elevator car and counterweight using mechanical scales, the invention uses a motor drive system to measure electrical parameters (current, voltage, power) during elevator operation. The balancing weight difference is calculated from these electrical measurements combined with a power model of the elevator system, eliminating the need for manual mechanical weighing operations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If manual weighing of elevator components is performed, then accurate balancing weight difference is obtained, but time consumption increases

Engineering Contradiction:

Improvebalancing weight differenceVSAvoidtime consumption

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent enables continuous measurement of the balancing weight difference through ongoing electrical parameter monitoring during normal elevator operation. The motor drive continuously measures current and voltage, and the power model continuously calculates the balancing weight difference, allowing for real-time monitoring without interrupting elevator service. This eliminates the time-consuming manual weighing process that requires stopping elevator operations.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The elevator's existing motor drive system performs the measurement function automatically as part of its normal operation. The motor drive already measures electrical parameters for control purposes, and the invention utilizes these existing measurements combined with the power model to self-determine the balancing weight difference without requiring external intervention or separate measurement operations.

Inventive Principle:

Principle #25Self-service

3Ease of operation

If simplified power model is used, then measurement process is simplified and costs reduced, but measurement precision may be affected

Engineering Contradiction:

Improvemeasurement processVSAvoidbalancing weight difference

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent employs a feedback mechanism where the power model parameters are continuously refined based on measured electrical parameters and calculated balancing weight difference values. The system compares calculated values with actual operational data and adjusts the power model parameters accordingly, ensuring high measurement precision while maintaining the simplicity of the measurement process. This feedback loop compensates for any simplifications in the power model.

Inventive Principle:

Principle #23Feedback

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 method significantly simplifies the balance check process, reducing effort and costs by accurately calculating the balancing weight difference using power model equations, with minimal error, and can be integrated into elevator control systems or maintenance tools.

Implementation Method 1

electrical parameters (current, voltage, power) are measured during operation of the elevator

Methodology Applied

Scientific EffectElectrical measurement:

Data Source

PatentUS9975730B2Method for determining the balancing weight difference in an elevator

Publication Date: 2018.05.22 KONE OYJ

AI summary

In a method for performing a balance check with an elevator, a power model of the elevator is established, including the motor power fed to the motor (PM) and power parameters of the motor and the moved components in the hoistway (PK, PP, PFr, PCu, PFe), a test run of the elevator is made, mid motor power values for the up and down direction are determined, i.e. the power fed to the motor at the instant when the car is moving through the middle of the travelling path of the elevator in up and down direction with constant velocity, the difference between the mid power value in up and down direction is determined, the balancing weight difference is obtained from said mid power value difference. This method allows an easy determination of the elevator balance preferably in course of modernizations of an elevator system with a new elevator motor.