Abstract: A wear sensor system, compressors using the wear sensor system and methods of detecting wear on a bearing. The wear sensor system includes a stationary housing mounted circuit comprising a first inductor electrically connected to a voltage source and a rotating shaft-mounted circuit comprising a second inductor electrically connected to a capacitor. When there is no metal-to-metal contact between the shaft of the compressor and the housing into which the shaft is mounted, the housing-mounted circuit inductively charges the shaft-mounted capacitor and reduces a current level when the shaft mounted capacitor is charged. Likewise, when there is metal-to-metal contact between the shaft and the housing (which is indicative of bearing wear), the shaft-mounted circuit is grounded; this causes the housing-mounted circuit to increase the current level. This increased current level may be output to a suitable device for display or other indicia of bearing wear.

Abstract: A fuel cell system that employs end cell heaters in the end cells of a fuel cell stack in the fuel cell system that consistently maintain the temperature of the end cells above the operating temperature of the stack so as to reduce water in the end cells. In one embodiment, the temperature of the end cells is maintained within the range of 80° C.-85° C. across the entire output power range of the fuel cell stack. In accordance with another embodiment of the invention, the end cells are electrically coupled in series, and the control signal for controlling the end cells heaters is selected to heat the warmest end cell to the desired temperature.

Abstract: A fuel cell system that employs end cell heaters in the end cells of a fuel cell stack in the fuel cell system that consistently maintain the temperature of the end cells above the operating temperature of the stack so as to reduce water in the end cells. In one embodiment, the temperature of the end cells is maintained within the range of 80° C.-85° C. across the entire output power range of the fuel cell stack. In accordance with another embodiment of the invention, the end cells are electrically coupled in series, and the control signal for controlling the end cells heaters is selected to heat the warmest end cell to the desired temperature.