High Temperature Sensor for Bearing Health Monitoring

The goal of condition based maintenance (CBM) is to minimize maintenance costs by scheduling and performing maintenance only as needed. Accurate estimates of component health are required for successful CBM. This paper presents a sensor for determining bearing health in harsh environments (e.g., turbine engines). The combined sensor and bearing, or "smart bearing", is autonomous, harvesting thermal energy from the environment and providing temperature and vibration data via wireless transmission. The sensor exploits recent developments in passive and active electronic components to operate at high temperatures (300degC). A unique method for measuring bearing cage motion is presented. Preliminary test results are reported and other potential applications are indicated.