Hi-tech sensors offers stator slot temperature sensors. To monitor the temperature of the winding of motors and generators a temperature sensor is installed in stator winding by inserting the stator slot sensor in the place of stator slot separators and then varnished along with the winding. This sensors-are manufactured in simplex/duplex/triplex type on a suitable base then encapsuled in si glass sheet/ptfe. These are the various stator slot temperature sensors: rtd, thermocouple and thermistor. Rtd is most suitable because it can be manufactured with a long sensing area, which provides an average temperature of a particular spot. Two types of rtds are manufactured. Wire wound sensors a uniform bifilar winding supported on suitable base so there will be no strain on wire and then encapsuled in si glass board iptfe. In thin film type a thin film element is encapsuled in si glass board iptfe. A thermocouple is encapsuled in si glass board/ptfe and placed in the slots and varnished. Various thermocouples used are k, j, t, e, etc. Thermistor is used as a signaling sensor for a pre-specified temperature. The change in the resistance of the thermistor goes exponential high or low depending on ptc/ntc above the pre-specified temperature.
