Engineers from the Samara company "PKF TSK" proposed an unusual way to monitor the condition of a gas turbine engine gearbox – without installing additional vibration sensors. For diagnostics, it is proposed to use a standard tachometer, which already measures the output shaft speed.
According to the idea, the signal from the standard sensor is converted into a spectrum, and the section corresponding to the shaft rotation frequency is isolated.
Then the system evaluates the shape of the spectral peak: it measures its width at the base and at half the maximum level. The difference between the two values is related to the amount of tooth wear.
The idea is that damage and wear of gears change the microgeometry of the meshing, increase backlashes and impact loads. Because of this, the shaft begins to rotate less uniformly, and the nature of its signal spectrum changes.
The main advantage of the approach is that it does not require installing separate vibration equipment on the gearbox housing and measuring high-frequency vibrations. The signal from the existing sensor can be analyzed directly during engine operation, including in flight.