Motor Bearing Wear Monitoring with Frequency-Based Signal Correction
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Solution Overview
Problem
Conventional motor bearing wear monitoring devices require manual adjustment of detection accuracy when the driving condition is changed by an inverter, leading to erroneous detection due to deviations in the corresponding relation between measured values and wear amounts.
Innovation Solution
A motor bearing wear monitoring device using multiple detection coils to detect changes in magnetic flux, with a storage unit storing correspondence information between wear amounts and voltage values, and a correction unit that adjusts these values based on driving frequency to maintain detection accuracy automatically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the driving condition is changed by an inverter, then energy efficiency is improved, but detection accuracy deteriorates due to deviation in the corresponding relation between measured values and wear amounts
Solution Approach 1:
The patent implements dynamic correction of the correspondence relation between detection coil outputs and bearing wear amounts based on the actual driving frequency. The correction unit automatically adjusts the correspondence information according to the current driving frequency, making the system adaptive to changing operating conditions without manual intervention, thus maintaining measurement precision while allowing driving condition changes for energy efficiency
Solution Approach 2:
The patent changes the parameter of correspondence information based on driving frequency. By storing multiple correspondence information sets corresponding to different driving frequencies and selecting the appropriate set based on the current frequency, the system maintains accurate wear detection across varying operating conditions, resolving the contradiction between energy-efficient variable speed operation and measurement accuracy
2Measurement precision
If manual adjustment is performed to maintain detection accuracy, then measurement precision is improved, but ease of operation deteriorates due to required manual intervention
Solution Approach 1:
The patent implements a self-service mechanism where the correction unit automatically performs the correction of correspondence information based on the detected driving frequency without requiring manual intervention. The system monitors its own operating conditions and autonomously adjusts the calibration parameters, eliminating the need for manual adjustment while maintaining high detection accuracy
Solution Approach 2:
The patent employs feedback control where the correction unit continuously monitors the driving frequency and uses this information to dynamically adjust the correspondence relation between detection coil outputs and wear amounts. This closed-loop feedback mechanism ensures measurement precision is maintained automatically, removing the burden of manual adjustment from the operator
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
The device maintains detection accuracy without manual operation, even when the driving condition changes, ensuring precise monitoring of bearing wear in canned motor pumps.
Implementation Method 1
by detecting a change in magnetic flux corresponding to a mechanical position change of the rotor with respect to a stator of a motor
Implementation Method 2
The monitoring device detects a voltage induced in the detection coils by the rotation of the motor
Data Source
AI summary
The motor bearing wear monitoring device (5, 5A) monitors wear states of bearings (32, 33) with detection coils (C1 to C8). The device includes a storage (56, 56A) storing correspondence information on wear amount of the bearing and a voltage value corresponding to the wear amount, a wear amount detection unit detecting the wear amount of the bearing, based on differences between each of the detection coils (C1, C3) and between each of the detection coils (C5, C7), and a difference between a combined signal of the detection coils (C2, C4) and a combined signal of the detection coils (C6, C8); a signal generation unit (53, 553) generating an amplitude signal, based on the detection signal or the combined signal that are used for generating the difference; and a correction unit (551, 554) correcting the difference or the correspondence information depending on a driving frequency, based on the amplitude signal.