Remote RF Signal Detection for Bearing Electric Discharge
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Solution Overview
Problem
Existing methods for detecting bearing currents in electric drive systems require dismantling and stopping the AC motor, making them cumbersome and time-consuming, and are not effective for indicating electric discharges within the bearing.
Innovation Solution
A method and device for remotely detecting radio frequency signals associated with electric discharges between a rolling element and a raceway in a bearing, using a magnetic or electric field sensor to estimate and indicate the discharge without interfering with the electric drive system, allowing for non-invasive monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Rogowski-type current sensor is used to measure bearing currents directly at measurement points within the AC motor, then measurement precision is improved, but device complexity and ease of operation deteriorate due to the need to stop and dismantle the motor
Solution Approach 1:
The patent replaces direct electrical measurement (mechanical contact via Rogowski sensor) with electromagnetic field detection. The detection device uses magnetic field sensors to sense the electromagnetic field generated by bearing currents externally, eliminating the need for physical access to internal measurement points and avoiding motor dismantling while maintaining measurement capability
Solution Approach 2:
The patent introduces the electromagnetic field as an intermediary between the bearing currents and the detection device. Instead of directly measuring current at internal points, the system detects the electromagnetic field generated by the currents externally, using the field as a mediator to transmit measurement information without requiring physical intrusion into the motor
2Measurement precision
If direct measurement points are accessed within the AC motor, then measurement precision is improved, but loss of time increases due to stopping and dismantling the motor
Solution Approach 1:
The detection device is pre-configured with appropriate magnetic field sensors and signal processing capabilities before deployment. The system is ready to perform measurements immediately upon placement near the motor, eliminating the need for time-consuming preparation, dismantling, and reassembly operations that would otherwise be required to access internal measurement points
3Ease of operation
If remote detection of radio frequency signals is used to indicate electric discharges, then ease of operation is improved, but measurement precision deteriorates due to signal processing requirements
Solution Approach 1:
The detection device incorporates signal processing that analyzes the characteristics of detected radio frequency signals, comparing them against known patterns of bearing discharge emissions. The system provides feedback through indication when discharge patterns are confirmed, enabling precise detection of electric discharges while maintaining remote operation capability through intelligent signal discrimination
Data Source
AI summary
The present invention relates to a method for indicating an electric discharge in a non-conducting medium (22) between a rolling element (20) and a raceway (16, 18) in a bearing (12) of an electric drive system (10). The method comprises: remotely detecting radio frequency signals emitted from the electric drive system, which signals comprise a radio frequency signal associated with an electrical discharge in the non-conducting medium, processing the detected radio frequency signals to estimate the electric discharge, and indicating the estimated electric discharge. The present invention also relates to a corresponding device (30, 50, 70, 90) for indicating an electric discharge in a non-conducting medium between a rolling element and a raceway in a bearing of an electric drive system.