Diagnostics Of Traction System Of Very High Speed trains: Experimental Results And Selection Of The Most Suitable Signal Processing Techniques

Traction equipment of very high speed trains (VHST) is characterized by high complexity and quality of the components and requires high reliability. An efficient maintenance approach like condition based maintenance (CBM) should be implemented to reduce the costs of preventive maintenance program. For this purpose, an experimental full scale test rig for the CBM of VHST traction equipment has been designed to investigate in detail, failures in the main mechanical components of system, i.e. motor, bearings and gearbox. The paper describes first the main characteristics of the testrig. Then, the results of a long test campaign is described in detail. Several damaged bearings, intentionally and artificially or owing to field use, have been installed (more than 60 configurations) and 12 different operating conditions, in terms of motor torque and speed, have been tested. Moreover, several signal processing techniques have been used, including the more traditional frequency and statistically based and the more sophisticated exploiting multi-domain and cyclostationarity approaches. Very positive results have been obtained and they prove, for the first time to best of authors’ knowledge, that, by positioning suitably the sensor and by using an appropriate signal analysis technique, bearing defects can be identified, even under heavy environmental noise. The results allow defining: i) the most suitable sensor position and type to be installed for each component and ii) the most suitable technique for signal analysis in order to monitor the distinct signature of impending faults of the bearings, gearbox and motor.