Temperature rise measurement in armature of a DC motor, under running conditions, by telemetry

The author presents a method to measure temperature, at various points in the armature of a DC series traction motor, under running conditions. Since the results of the `slip-ring & brush´ method using thermocouples were not at all reliable, two sophisticated methods of temperature recording were considered: (i) the multi-channel rotary transformer (MCRT) along with amplifier and data recorder; and (ii) the development of a tailor made telemetry system for data communication from the armature to the stator without involving any moving contacts between the two. The telemetry system was chosen to suit a particular type of traction motor used extensively on main line electric locomotives