Traction Motor in-service multi-technology condition monitoring

In January 2007 an investigation was carried out by PCMSEng into C317 rapid Traction Motor brush-wear problems. After a detailed review it was widely accepted by fleet owners and maintainers that the correct way forward would be to factually establish the root cause of this problem by implementing a multi-technology monitoring programme on selected motors. This action would involve taking known ´good´ and ´bad´ motor units, installing sensors, conducting identical test runs whilst collecting and trending condition data to establish the in-service forces acting on the motors. From the collation and analysis of this data, a process of elimination will result in the root cause of failure being identified. Stresswave and temperature sensors were installed on the gearbox, axle box, traction motor casing and traction motor brushes. A ´control´ accelerometer was also positioned vertically on the axle box on the gearbox side of the axle. The aim of the ´control´ point was to measure the level of vibration/stresswave created externally to the gearbox for comparison and correlation with the gearbox, traction motor and internal motor measurements. Bullet cameras were mounted on the underframe of the train internally to the traction motor. Sensors installed on the brushes have been specifically designed by PCMS to have a frequency response characteristic optimised for detection of vibration/temperature and ultrasonic signals. The accelerometers reduced diameter allowed for the sensor to be mounted on each brush position around the commutator. All sensors were bonded to the brush with a small section of bakalight between the sensor and the brush to provide sensor electrical isolation. A two week testing period was scheduled and achieved Across the C317 operating route during this period various motor conditions were monitored on two separate C317 trains. For the purpose of this, paper results for one out of the four motors are presented.