| 摘要 |
PURPOSE:To reduce misdiagnoses by providing an arithmetic means which calculates the re-averaged values of voltage signals between every couple of commutators and decides that a commutator segment between abnormal re-averaged values is abnormal. CONSTITUTION:A label 30 is stuck on a commutator segment 12 at one optional position and a label detector 32 which detects the label 30 is provided to the outer periphery of the segment 12 to constitute a reference point detection part. Then when the segment 12 as a reference point reaches a specific position, a reference point detection signal is obtained from the reference point detection part. A couple of contactors 10 which receive this signal detects voltage signals between every adjacent segments 12 and a microcomputer 38 calculates the mean value of voltage signals between every couple of segments 12. Then the abnormality of a segment 12 is decided from the ratio of the re-averaged value calculated from the ratio of the voltage signal and its averaged value and the total average value of the whole commutator which is calculated from the re-averaged value. Therefore, noises of an electric signal generated owing to a defect in the contact of a contactor 10 are removed, so the possibility of misdiagnoses due to the noises is extremely low.
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