Abstract: A system for determining a health status of a positive temperature coefficient resistor (PTCR) heater assembly includes a PTCR heater assembly and a health monitoring system. An input voltage is provided to the PTCR heater assembly to provide heating. The health monitoring system includes a first sensor configured to sense the input voltage at the PTCR heater assembly and a second sensor configured to sense a current through the PTCR heater assembly. The health monitoring system is configured to determine a baseline characteristic and an observed characteristic each relating to an inrush peak of the PTCR heater assembly and based on the input voltage and the current. The health monitoring system compares the observed characteristic to the baseline characteristic to assess a health status of the PTCR heater assembly and outputs the health status for PTCR heater assembly diagnostics and/or prognostics.

Abstract: A system for determining a health status of a positive temperature coefficient resistor (PTCR) heater assembly includes a PTCR heater assembly and a health monitoring system. An input voltage is provided to the PTCR heater assembly to provide heating. The health monitoring system includes a first sensor configured to sense the input voltage at the PTCR heater assembly and a second sensor configured to sense a current through the PTCR heater assembly. The health monitoring system is configured to determine a baseline characteristic and an observed characteristic each relating to an inrush peak of the PTCR heater assembly and based on the input voltage and the current. The health monitoring system compares the observed characteristic to the baseline characteristic to assess a health status of the PTCR heater assembly and outputs the health status for PTCR heater assembly diagnostics and/or prognostics.

Abstract: A methodology includes circulating a temperature-controlled and flow-rate-controlled medium through a container at a controlled flow rate and submerging a thermistor with the medium. With the thermistor submerged, a power output of the thermistor is determined and compared to a power criterion, after which classification of the thermistor occurs based on a comparison of the power output to the power criterion. The methodology can include submerging a reference thermistor within the medium and determining a reference power output of the reference thermistor with the reference thermistor submerged within the medium, the power criterion determined based on the reference power output.