Compressor Bearing Failure Prediction via Sealability Change
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Solution Overview
Problem
Existing failure detection systems for compressors, such as those described in PTL 1, fail to predict compressor failures at an early stage, leading to significant damage of the target portions before detection.
Innovation Solution
A compressor system that includes a prediction device to predict failures in bearings and drive shafts by monitoring changes in indices like internal pressure, polytropic index, temperature of discharge gas, workload, refrigerating capacity, compression torque, motor signal waveform, vibration signal, and sound intensity, rather than relying on detecting a decrease in lubricating oil levels, allowing for early detection of potential failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If failure detection is based on detecting decrease in lubricating oil levels, then the detection method is simple, but the detection timing is late and significant damage occurs before detection
Solution Approach 1:
The patent replaces mechanical/oil-based detection methods with electrical measurement methods. Instead of detecting oil level decreases mechanically, the system uses current analysis of the motor drive system to detect bearing failures electrically, enabling earlier detection before significant damage occurs.
Solution Approach 2:
The patent introduces an intermediary detection approach by measuring the current consumed by the motor drive system. This current signal serves as an intermediary indicator that reflects bearing condition without requiring direct observation of the bearing or oil levels, allowing for indirect but earlier failure detection.
2Ease of operation
If monitoring oil levels is used to predict bearing failure, then the system is simple to implement, but the oil level decrease is difficult to detect and timing is delayed
Solution Approach 1:
The patent substitutes mechanical oil level monitoring with electrical current analysis. The motor drive system's current consumption is measured and analyzed to detect bearing failures, providing earlier warning signals without the complexity of mechanical sensing systems.
Solution Approach 2:
The system uses the motor drive system's own current consumption characteristics as the detection signal. The motor drive system serves dual purposes: operating the compressor and providing the detection signal for bearing failure prediction, eliminating the need for separate monitoring systems.
3Measurement precision
If q-axis current analysis is used to detect compressor failure, then detection accuracy is improved, but the timing is still late and cannot predict failure before significant damage
Solution Approach 1:
The patent applies preliminary action by analyzing current consumption patterns before actual bearing failure occurs. By continuously monitoring and analyzing the motor drive current, the system can detect early signs of bearing deterioration and predict failure before significant damage occurs, enabling preventive maintenance.
Solution Approach 2:
The system implements feedback by continuously monitoring motor drive current consumption and using this information to predict bearing failure. The current analysis provides ongoing feedback about bearing condition, allowing the system to detect and predict failures at early stages through iterative monitoring and pattern recognition.
Data Source
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AI summary
A compressor system (40) includes a compressor (50), and a prediction device (21) configured to predict a failure of a bearing (79, 69, 93) and a drive shaft (80) of the compressor (50). The compressor (50) includes a motor (55), a compression section (60), the drive shaft (80), and the bearing (79, 69, 93). Lubricating oil is supplied from a common oil supply source to the compression section (60) and to a sliding portion of the drive shaft (80) and the bearing (79, 69, 93). The prediction device (21) includes a failure prediction unit (23) configured to predict the failure of the bearing (79, 69, 93) and the drive shaft (80) based on a change in an index indicating deterioration of sealability of the compression chamber (61).