Using signals from the gas-turbine engine shaft speed sensor in the diagnosis of the technical condition of its reduction gearbox

Abstract

It is shown that analyzing the signals from standard sensors of gas-turbine engine shaft speed we can resolve some issues of diagnostics of the technical condition of the reduction gearbox without installing any additional vibration transducers. It was found, in particular, that the vibration spectrum component generated by the wear of the differential reduction devices gear teeth causing resonant oscillations of the turbocharger blades produces torsional vibration at the appropriate frequency. The analysis of the parameters of the instantaneous rotational speed of the reduction gear output link (the shaft of the rear screw) made it possible to obtain some diagnostic indicators of the value of the reduction gear teeth wear on the basis of evaluation of the frequency deviations variance. It was established that the value of the diagnostic indicator is linearly dependent on the value of wear. The norm for this indicator was established for the engine under investigation. Significant influence of the load on its level was shown.

Keywords

• gas-turbine engine
• differential speed reduction device
• rotor speed sensor
• diagnostic parameter
• torsional vibration