| 摘要 |
PURPOSE:To diagnose easily whether a rupture of a bar exists or not, without stopping a motor, by providing a frequency analyzing circuit, the first heat frequency calculating circuit, and amplitude ratio calculating circuit, etc. CONSTITUTION:A frequency component is branched and distributed to the first beat frequency calculating circuit 5, an amplitude ratio calculating circuit 6, and a power source frequency selecting circuit 7. A beat frequency of the circuit 5 is displayed by the first beat frequency displaying circuit. Next, the circuit 6 derives a ratio of a voltage amplitude having a frequency component and a voltage amplitude of a fundamental frequency, and brings this value to an amplitude ratio display 9. Also, the circuit 7 extracts only a center frequency and sends it to the second beat frequency calculating circuit 15. A bearing vibration detector 10 inputs vibration from a rotor of an induction motor 17, to a bearing vibration amplifier 11, and applies this output to a revolving speed analyzing circuit 12. By the circuit 12, a rotational frequency component is analyzed, and only a center rotational frequency is extracted by a rotational frequency selecting circuit 13. Also, in the circuit 15, outputs from the circuits 7, 13, etc. are calculated, and the second beat frequency is displayed 16. |
