Method and device for indicating an electric discharge inside a bearing of an electric drive system
First Claim
1. A method for estimating an occurrence of an electrical discharge in a lubricant between a rolling element and a raceway in a bearing of an electric drive system, the method comprising:
- remotely detecting radio frequency signals emitted from the electric drive system;
filtering the radio frequency signals remotely detected to exclude radio frequency signals that may be associated with surrounding equipment or a gear box of the electric drive system;
processing the filtered radio frequency signals to determine if they are non-repetitive, and have a frequency spectra within a range of 50 MHz-8 GHz, and have a duration shorter than 200 ns;
estimating that an electrical discharge has occurred in the lubricant between the rolling element and the raceway in the bearing of the electric drive system in response to a determination that the filtered radio frequency signals are non-repetitive, and have a frequency spectra within a range of 50 MHz-8 GHz and have a duration shorter than 200 ns as these parameters are indicative of the occurrence of the electrical discharge in the lubricant between the rolling element and the raceway in the bearing of the electric drive system, andnot estimating that an electrical discharge has occurred in the lubricant between the rolling element and the raceway in the bearing of the electric drive system in response to a determination that the filtered radio frequency signals have a frequency spectrum outside the range of 50 MHz-8 GHz and have a duration longer than 200 ns.
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Accused Products
Abstract
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.
10 Citations
19 Claims
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1. A method for estimating an occurrence of an electrical discharge in a lubricant between a rolling element and a raceway in a bearing of an electric drive system, the method comprising:
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remotely detecting radio frequency signals emitted from the electric drive system; filtering the radio frequency signals remotely detected to exclude radio frequency signals that may be associated with surrounding equipment or a gear box of the electric drive system; processing the filtered radio frequency signals to determine if they are non-repetitive, and have a frequency spectra within a range of 50 MHz-8 GHz, and have a duration shorter than 200 ns; estimating that an electrical discharge has occurred in the lubricant between the rolling element and the raceway in the bearing of the electric drive system in response to a determination that the filtered radio frequency signals are non-repetitive, and have a frequency spectra within a range of 50 MHz-8 GHz and have a duration shorter than 200 ns as these parameters are indicative of the occurrence of the electrical discharge in the lubricant between the rolling element and the raceway in the bearing of the electric drive system, and not estimating that an electrical discharge has occurred in the lubricant between the rolling element and the raceway in the bearing of the electric drive system in response to a determination that the filtered radio frequency signals have a frequency spectrum outside the range of 50 MHz-8 GHz and have a duration longer than 200 ns. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A device for estimating an occurrence of an electrical discharge in a lubricant between a rolling element and a raceway in a bearing of an electric drive system, comprising:
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a magnetic field sensor configured to remotely detect a magnetic field emitted from the electric drive system; and a signal characteristic determining processor configured to determine when the magnetic field remotely detected includes magnetic field signals having parameters indicative of an electrical discharge in the lubricant between the rolling element and the raceway in the bearing of the electric drive system, and produce an output to signal that an occurrence of an electrical discharge in the lubricant has occurred when the magnetic field signals are non-repetitive and have a frequency spectra within a range of 50 MHz-8 GHz and have a duration shorter than 200 ns and not produce an output to signal that an occurrence of an electrical discharge in the lubricant has occurred when the magnetic field signals have a frequency spectra outside the range of 50 MHz-8 GHz and have a duration longer than 200 ns. - View Dependent Claims (8, 9, 10, 11, 14)
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12. A method for indicating an electric discharge in a lubricant between a rolling element and a raceway in a bearing of an electric drive system, comprising:
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remotely detecting radio frequency signals emitted from the electric drive system, processing the detected radio frequency signals to determine whether the detected radio frequency signals include a radio frequency signal shorter than 200 ns and having a frequency spectra within a 50 MHz-8 GHz range, indicating the electric discharge if the radio frequency signals include the radio frequency signal shorter than 200 ns, and having a frequency spectra within a 50 MHz-8 GHz range and not indicating the electric discharge if the radio frequency signal is longer than 200 ns and has a frequency spectra outside the 50 MHz-8 GHz range. - View Dependent Claims (13, 15, 16)
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17. A device for estimating an occurrence of an electrical discharge in a lubricant between a rolling element and a raceway in a bearing of an electric drive system, comprising:
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a magnetic field sensor configured to remotely detect a magnetic field emitted from the electric drive system; and a signal characteristic determining processor configured to determine when the magnetic field remotely detected includes magnetic field signals having parameters indicative of an electrical discharge in the lubricant between the rolling element and the raceway in the bearing of the electric drive system and to produce an output to signal that an occurrence of an electrical discharge in the lubricant has occurred in response to a determination that the magnetic field signals have a frequency spectra within a range of 50 MHz-8 GHz and have a duration shorter than 200 ns and to not produce an output to signal that an occurrence of an electrical discharge in the lubricant has occurred in response to a determination that the magnetic field signals have a frequency spectra outside the range of 50 MHz-8 GHz and have a duration longer than 200 ns. - View Dependent Claims (18, 19)
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Specification