View Full Version : Trane RTAA125 winding temp.
10-12-2006, 07:12 PM
I was checking a chilled water loop today and noticed that one of the Trane screw chillers had a “Winding Temp. fault on compressor B“. I was informed by one of the maintenance guys that they have had several of these faults over the past few months but were able to reset them. It won’t reset this time and the compressor is cool to the touch, except by the CCH. This building has had a bad history of voltage problems over the years, they are on the end of the power lines. During the hottest and coldest days of the year, it is common to have several "Severe Phase Unbalance" faults over a 24 hour period. The Electric Co. has made some corrections, but I don’t think the power is much better.
Does anybody have any ideas regarding the Winding Temp. fault, what should I look for?
10-12-2006, 07:35 PM
megger the windings,and do a visual on the contactors for carbon arking..the unit might just be doing its job and picking up that voltage bouncing around,remove the wires and ring out the sensors at the pecker head also
10-12-2006, 11:44 PM
Meg your motor, phase-phase & to ground. Check your connections @ the terminals on peckerhead, and @ the Comp. Module. Put a jumper across inputs, if that does not get it the module could be bad.
10-13-2006, 08:53 PM
are the temp terminals showing open? Pull the leads off carefully, wire brush and put new spades on if needed and try again
10-18-2006, 11:38 PM
Did you check the motor winding temperature thermostat which will open at 221F when there is an overheating problem? This thermostat should be located on top of the compressors and has a reaction time of 0.5 to 2.0 seconds.
10-19-2006, 08:00 PM
I haven't had much time to look into the problem much further. This is a big account and I have been doing the heating check-outs under the maintenance contract. The chiller work will be an extra and the customer doesn't want to spend the money right now, maybe next month. I did do a little checking on my own time, all the electrical connections are tight and the compressor windings are not open, nor is the winding thermostat. I don't have a megger on my truck, but I did use my Fluke meter to check the windings. I jumped out the winding thermostat and the compressor started, I then removed the jumper while it was running and it stayed on. I then shut it down, put the peckerhead cover back on and tried to restart the compressor, but it had the same fault. Thinking about it now, I think it faults out before the contactor even pulls in, looks to me like the winding thermostat is bad, what do you guys think? I haven't ever changed one before, could someone walk me through the procedure of changing the winding thermostat?
Thanks for all the replies so far.
[Edited by hands on 10-20-2006 at 07:07 PM]
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