RTAA125

[soonera/c]

We have two of these machines and have lost two compressors shorted to ground in the last month. They are fairly new with only 20,000hrs of run time. Anyone else have any experience like this?

[scott123]

Burnouts on RTAA's in general are very rare. My guess there is another "operational" problem that exists, which is resulting in a repeated issue.

Other than that; The system wasn't properly cleaned the 1st time it burned.

[maxster]

did you note the run hours and start counts on the failed compressors

[soonera/c]

Each compressor had about 4500 starts. I am talking about two different machines here. One compressor failure on each machine. All kinds of wierd codes reverse phases, phase loss, high discarge temp. I have continuity to ground on all but one leg. Little strange.

[maxster]

so you basically have 4 compressors but are running one on each chiller and those are the ones with the starts..take the starts and divide that into the run hours for each and see the on times on all 4..if the contactors weren't changed from the first burn outs do a visual on them disconnect oll the line wires and megger out the contactor as you maually push the bar in per leg and between legs...are you 460 3 phase on that unit...flash guards up on the contactor?if you see that the contactors were brushed/cleaned and not changed or a dry run wasn't performed after the new compressors call in the Calvary bigtime before new stuff is put in.

[soonera/c]

Lemme back up here. Two different machines. Two different locations. One 460V unit and one 230V unit. One compressor (460V)shorted out last month TRANE replaced it. Now on another(230V) machine compressor has shorted out. TRANE will replace that also. I am not getting involved in a $15,000 compressor. As far as what the factory does for replacement on contactors and what ever I don't know what they did to the first one I haven't looked at it yet, been a little busy.

[maxster]

to cover thy ass.......they need to proof a dry run on that transition starting of those compressors and note on there paper work that the contactors are solid and don't need changeouts.

[acjourneyman]

I have never seen an RTAA compressor short out in 15 years but it is a compressor and they will burn out.Contactors on large compressors rarely ever get changed out on a burn out , simply because of the cost and rarely is it a contactor problem.Alot of these are across the line so not much to dry run either.

[service guy]

Check for Carbon Tracking!! This is very common on this compressor and can fool you into thinking you have a short!

[soonera/c]

I have the leads disconnected from the motor and have continuity on 5 of the six to ground. I know what carbon trails can do but don't see how in this case. Please explain further.

[techrider]

No insult intended just a question. Is meter set at meg ohms or K ohms. I have had people make that oversight and think compressors where grounded that were not.

[prideclaw]

Have these systems had oil samples taken and analyzed lately?That is essential on RTAA's.

[jimbob73]

You stated that the units had all kinds of wierd codes like reverse phases, phase loss, high discarge temp. Sounds like the compressors had a history of diagnostic shutdowns that were just reset everytime and not looked at what caused them, Which led to failure?