Real Time Condition Monitoring of Electric Propulsion and Generation System Using Passive Battery-Free RF Temperature Sensor

Real time passive RF temperature sensors used to wirelessly monitor the temperature of components such as rotors, stators, and windings used inside of generators and motors within electric propulsion systems are presented here. Sensors have been installed onto windings which rotate at full speeds (6,000 rpm, 5,000g) and temperatures above 140°C. Full system tests on electric motor rotors in multiple motor rig spin tests have been performed at speeds to 10,000rpm and 16,000g along with temperatures above 175°C in the presence of very strong (> 1 Tesla) and dynamic magnetic fields. Rotor temperature was monitored and experimentally evaluated and demonstrated. The system uses passive wireless sensors that can attach to the windings, rotor, magnets, disk, or shaft of a generator or electric motor used in onboard electric propulsion systems. Using a magnetically insensitive wireless measurement system, the temperature was monitored and recorded in real time. The sensors were interrogated using high temperature silicon dioxide co-axial cable antenna using radio frequency resonance-based sensing. The sensor-antenna set up was employed for temperature monitoring in a high magnetic flux metallic environment. Real time temperature monitoring was provided by indigenous software (Turbotrack).