A new approach for a train axle telemetry system

The application of a telemetry system for train axle fatigue monitoring is analyzed in this paper. Monitoring of the axle bending deformation at critical points is of great importance for both high speed and freight trains. The fatigue life of the axle may be significantly reduced due to accidental peak loads. Commonly used telemetry systems require special pick-ups for transmitting electrical power to the electronics placed on the rotating axle and for transferring back sensor signals. Inductive power transfer is performed through a high frequency magnetic field linking a rotating winding. Sensor signals are modulated on top of the power signal and transferred at an even higher frequency to be immune to the inductive magnetic field. In this paper a new approach for an inductive power transfer system, completely decoupled from the transfer of sensor signals, is analyzed. The layout of the energy transmission system has been simplified with respect to traditional telemetry systems and its efficiency is increased. Also the immunity of the measurements against the power magnetic field, the distance of the power head and all the electrical noise induced results have been improved. The combination of a simple power induction system, a fast data processing unit and a low power RF data transmission system lead to an easy and reliable telemetry system for train axle monitoring.