Rotating Machine Diagnosis Using Non-Copper Load Loss
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Solution Overview
Problem
Existing rotating machine diagnosis systems struggle to accurately diagnose abnormalities beyond copper loss, as they are influenced by power supply fluctuations and do not account for the state of connected equipment, leading to incorrect threshold settings and missed failure alerts.
Innovation Solution
A rotating machine diagnosis system that utilizes a detection unit to measure running load characteristics, compares them with product specifications, and displays information when load losses such as mechanical and floating losses exceed predetermined ranges, thereby accurately identifying abnormal states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current measurement is used for rotating machine diagnosis, then abnormal states can be detected, but power supply fluctuations cause measurement errors and false diagnoses
Solution Approach 1:
The patent introduces an equivalent circuit model as an intermediary between the power supply and the diagnosis system. By modeling the power supply characteristics (voltage fluctuations, impedance) and the connected equipment (reactors, capacitors, other motors) in the equivalent circuit, the system can calculate and compensate for their influence on current measurements, thereby eliminating false diagnoses caused by power supply fluctuations
Solution Approach 2:
The system implements feedback by continuously monitoring power supply voltage and using the equivalent circuit model to calculate the expected current under normal conditions. This calculated expected current is fed back to compare with actual measurements, allowing the system to identify and correct for power supply-induced deviations in real-time
2Extent of automation
If threshold values are set for abnormality detection, then diagnosis can be automated, but incorrect threshold settings lead to false positives or missed failures
Solution Approach 1:
The system performs preliminary action by pre-calculating and storing expected current values and thresholds in the equivalent circuit model before actual diagnosis occurs. These pre-established benchmarks account for normal variations due to power supply fluctuations and connected equipment, enabling reliable automated comparison during operation without requiring manual threshold adjustment
Solution Approach 2:
The patent dynamically adjusts diagnosis thresholds based on changing operating conditions by using the equivalent circuit model to calculate condition-specific expected values. Instead of fixed thresholds, the system adapts thresholds according to actual power supply characteristics and load conditions, maintaining high reliability across varying operational states
3Device complexity
If only copper loss is monitored, then simple measurement is possible, but other load losses (mechanical loss, floating loss) cannot be specified
Solution Approach 1:
The patent applies segmentation by decomposing the total load loss into distinct components (copper loss, iron loss, mechanical loss, floating loss) within the equivalent circuit model. Each loss component is represented by separate circuit elements and calculation equations, allowing the system to measure and specify individual loss types rather than treating them as a single aggregate value
Solution Approach 2:
The system replaces direct mechanical measurement of various losses with an electrical circuit modeling approach. By substituting physical measurement devices with an equivalent circuit model that calculates losses based on electrical parameters (current, voltage, power factor), the system achieves comprehensive loss specification while maintaining measurement simplicity
Data Source
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AI summary
The purpose of this invention is to provide a rotating machine diagnosis system for specifying the state of a rotating machine using load loss of the rotating machine. In one example of a rotating machine diagnosis system according to this invention, to achieve this purpose: provided are a rotating machine having a load connected thereto, a detection unit for detecting a running load characteristic when the rotating machine is running, a storage unit, and a control unit; a product load characteristic based on product specifications provided by the manufacturer of the rotating machine is stored in the storage unit beforehand; and the control unit stores the running load characteristic detected by the detection unit in the storage unit and, on the basis of the product load characteristic, uses iron loss and copper loss to specify load loss other than the iron loss and copper loss in the running load characteristic, and if the other load loss exceeds a predetermined range, causes the display unit to display information presuming that the running load characteristic is abnormal.