cvhd circuit 2 trip on motor temp#3 windin

[hservice]

I have a cvhd that is tripping on motor temp cir 2 winding 3. Checks i have made are as followed. At full load conditions refigerant pump output pressure is about same as cir 1 slightly higher due to higher condensing pressure. Refrigerant temp in and out of motor( 90 ent 93 leav) no air in system 2 degree approach on condenser. Motor housing temp never gets above 105 but winding jumped from 97 to 147 to 126 to 147 and tripped immediately jumped to 275 then back down to 93 whithin 2 min. I believe the sensor is bad. Any ideas machine is an 06 model. Another bit of information machine tripped on same winding when it was secured. Just want a second opinion before i install resistor.

[CV_Geardrive]

Hi,
I suppose you are talking about CVHG chiller.
Usually in TRANE CTVs the high motor temperature cut out is 250°F.
This is winding temperature. While winding is 250, the shell of motor is about 140.
It is not strange to have one thermistor with higher temperature but for sure is strange this thermistor to jump like this and trip the unit even if it is stopped.
If operation of motor is normal (Amps, volts, voltage drop across contactors contact voltage and current asymmetry etc.) and MΩ readings are ok then you should remove the cable of this thermistor and put a ¼ W, 75Ω resistor in the triplex module.
If you lose another thermistor then you should place 2 surface thermostats in the two cooling return lines in order to cut out unit if the temperature rises above 120. (place them before oil cooler)
If you lose the 3rd thermistor then place a surface thermostat to motor shell in order to cut out unit if the temperature rises above 140. (Or you can replace the motor!!!!!)
Hope it was helpful
Regards,
CV

[hservice]

Cdhf 2170 sorry for typo...all motor running measurements were within range. motor shell never went over 105. thank you for the help