| 摘要 |
PURPOSE:To judt the abnormality of a blade mounted to a rotor by detecting and storing the frequency output from the acoustic wave obtd. by hammering the blade and comparing the same with the frequency output of the next blade. CONSTITUTION:When a blade 2 is hammered, the oscillation sound thereof is collected with a microphone 6 and is inputted to a frequency detection circuit 7; therefore, the specific frequency with said blade 2 is detected in synchronization with the timing signal from a transmitter 8. The detected frequency detection signal is supplied to an arithmetic section 9 and is temporarily stored in a storage device 12. The frequency of the blade 2A obtd. before the same and the frequency obtd. from the blade 2 are compared in a comparator 13, and when there is a difference of a prescribed value or above between both frequencies as a result of the comparison, the section 9 discriminates the presence of abnormality and supplies the abnormality signal to an abnormality announcing means 11. |
