Trane RTAC 170 , Phase reversal trip?

[THE WOMBAT]

Hi Gents

Just wondering what is the cause of (Phase reversal - Cprar 1A) trip.
I thought our monthly generator tests where causing the CH530 controller to see a phase failure or voltage dip.

A download of the log has revealed its been happening a few times this month. :rolleyes:

If someone could point me in the direction of this problems origin would be of great help.

The Trane guy said its nothing to worry about, Till i downloaded the log and there are multiple latching shutdown request. :eek:

Cheers guys

[Grizzly]

Hi Wombat.
Sadly your attached thumbnails are not to clear.
Anyway just a long shot I know.
But does these phase reversals coincide with the bad weather we have been having.
The reason I ask is because in the more rural areas whenever bad weather occurs.
The National grid guys switch grids, causing power surges and voltage drops.
Especially if you are at the end of a grid?
Not that they will admit this of course!
Incidentally the power output is seasonally adjusted at the Power Stations.
To try and balance demand with supply (weather related).
I know these are not likely causes especially as yours is phase related.
But worth consideration all the same!
Grizzly

[nh3wizard]

At a facility I used to work for we had similar problems, it was from another user down the road a bit, and every time he started or stopped some of his bigger machines the was a drop or raise the voltage... they ended up switching where he received his power from.

Just a thought.

[THE WOMBAT]

Hi Grizz

We didnt have any power dips on these days as we have citect E.M.S. power monitoring on our data centre's incoming supplies. I think that the labeling isn't the best on this trane alarm, ''phase reversal" to me sounds like someone changed the red, white or blue phases around! which i know hasn't happened.
I think maybe something to do with the power sensing devices , C.T.'s or Voltage sensors on the boards.

[Grizzly]

Hi Grizz

We didn't have any power dips on these days as we have citect E.M.S. power monitoring on our data centre's incoming supplies. I think that the labeling isn't the best on this trane alarm, ''phase reversal" to me sounds like someone changed the red, white or blue phases around! which i know hasn't happened.
I think maybe something to do with the power sensing devices , C.T.'s or Voltage sensors on the boards.


You could be right!
Wombat!

Lets see what any of our "Trane Guys" have to say eh!
Grizzly

[cool_tech]

hi womby
is it a phase loss or phase reversal trip?
if you look at the wiring diagram you will se the hp is wired up throught a phase fail device. if you take off the front of the hp control you will see a little red button press that in and it will fix your phase loss problem.

[THE WOMBAT]

Hi cool tech

My engineers have been telling me that they have been resetting the alarm on the controller touch screen, so to me its not a manual reset problem. I haven't personaly seen this problem myself, but pretty sure its being reset on the controller, i will check out this Hp red button though.
Thanks

P.s if you click the link on my first post and expand the window as wide as possible, you can clearly see the alarm log that was downloaded with the trane software.

[Grizzly]

The Wombat if cooltech has advised a manual reset then give him the credit he deserves. (until proved otherwise!)
If in an alarm condition a digital controller will always revert to fault.
When a manual reset is required.
Coz the fault has not been reset!
Thats normally the score anyway!
Grizzly

[THE WOMBAT]

Grizzly
All advice i receive is always taken in, i wasn't discrediting anything that was said. I was one of those barstard kids that always asked why? and how come? :)

Im not sure as the machines runs that compressor again after the reset on the controller
(My maintenance guys aren't fridgies, and they wouldnt do anything but look at the controller)

if the hp is a manual reset, i would of thought that the controller would NOT allow the compressor to run if it had tripped on HP and was a manual reset.


Cool tec, I will be definitely checking the hp. Will let ya know tomorrow


Cheers

[Grizzly]

Wombat.
Well I will go and find a corner to hide in.:o
I must learn how to interpret what people mean better.

Good luck and I hope you find your answer.
Grizzly

[cool_tech]

hey womby make sure they use an insulated screw driver live wires in there and it is the red colored button in the middle. cover of the hp/lp to be taken off. this fault will reset by the ch530 but the comp will not run and fault will come up.
more infoo @ trane.com

ct
whats a wombat doing in england?

[nike123]

I don't know anything about Trane, so my questions could be total miss.:D

From your log, it is obvious that error is occurring on compressor A1. Is there more compressors in that chiller?

What device is sensing phase reversal?

Does electrical diagram of that chiller could be uploaded so that we have reference.

[THE WOMBAT]

Hi Guys

Sorry so busy, i haven't had a chance to look at the Trane RTAC 170 chiller yet.
NIKE123 it has two compressors, CH530 trane controller, haven't found leco diagram yet, but will find it. Not sure if there is a power sensing board in the chiller , as Cooltec says that the hp/lp could be wired in series with this sensing board or something else :confused:

What i have been doing is batteling with a McCrappy chiller (otherwise know as Mcquay) Blasted corel pipe sensors, they die and go out of cal with weeks of each other. got 4 x ALS 273 units. Then they start pumping out 2*c water when the sensor fails, Then out dry air coolers dump energy to atmosphere , cause water is below ambient temp. EErrrr:off topic:

Break down engineering design !, the only way these cow boys can make money in an advancing world!

Mcquay password to adjust sensors cal: (orange blue print blue) ! for digital password....
DIE McCrappy!

[nike123]

Since error is related only to one compressor it is not likely that power source is problem. Now question is where and what is sensing phase failure to further localization. We need el. diagram.

What are compressor protection devices on compressors since some Kriwans have phase failure protection and could send that alarm to control?

[Lowrider]

A RTAC 170 has two 85 ton screw compressors!

Has the compressor been runing since or not? What version of MP software is in the chiller?
What type of CT's are in, all the same?

What version of Techview do you use?

[THE WOMBAT]

Cooltec : I Checked the HP switch and it hadn't tripped.

The chiller must have a fault on the electrical sensing board equipment.

BUT WHAT I DID FIND!

On out monthly generator runs i noticed that our BMS system sends a high temp setpoint to the enable signal to the chiller (i.e. it monitors the return chilled water building temp and when the supply hits 10*c the signal is sent to enable the chillers, with there internal setpoint of 5*c) The chiller has its local setpoint set at 5*c, so when black out happens the chillers go offline till the supply water temp hits 10*c takes about 15mins. The genny start up only takes 15 seconds, 30 to latch onto the bars.



Then the chillers start up full wack , about 600 Amps a phase between two units. This is on a saturday when building load is low, but we have had problems with generators peaking on full load capacity week days in summer ! :rolleyes:

Well haven't sorted the phase reversal problem yet but have worked out why our generator system has been almost stalling because of this peak loading condition.

If the bms delayed the chiller enable for 1min, then allow the chiller to operate at its normal setpoint , it would only run, i think one compressor on each pack unit. This would stop the peak current loading on the generators and keep the chilled water temp under control :cool:

Much bigger problem sorted with a smaller one! thats engineering algebra!

[Grizzly]

Cooltec : I Checked the HP switch and it hadn't tripped.

The chiller must have a fault on the electrical sensing board equipment.

BUT WHAT I DID FIND!

On out monthly generator runs i noticed that our BMS system sends a high temp setpoint to the enable signal to the chiller (i.e. it monitors the return chilled water building temp and when the supply hits 10*c the signal is sent to enable the chillers, with there internal setpoint of 5*c) The chiller has its local setpoint set at 5*c, so when black out happens the chillers go offline till the supply water temp hits 10*c takes about 15mins. The genny start up only takes 15 seconds, 30 to latch onto the bars.



Then the chillers start up full wack , about 600 Amps a phase between two units. This is on a saturday when building load is low, but we have had problems with generators peaking on full load capacity week days in summer ! :rolleyes:

Well haven't sorted the phase reversal problem yet but have worked out why our generator system has been almost stalling because of this peak loading condition.

If the BMS delayed the chiller enable for 1min, then allow the chiller to operate at its normal setpoint , it would only run, i think one compressor on each pack unit. This would stop the peak current loading on the generators and keep the chilled water temp under control :cool:

Much bigger problem sorted with a smaller one! thats engineering algebra!

Thanks Wombat.
A good explanation of what does indeed look like a contributory factor.
Not quite sure as to why the comps/ chillers should start up so violently.
Just a thought!
Is there a start delay timer somewhere that could be staggered?
I assume that the chiller control strategy runs independent of the remote run signal (BMS).
Anyway good luck with this one , it seems you are getting there?
And thanks for getting back to us all, it is
always nice to be kept informed!
Grizzly

[centrifs]

Wombat, You could send a BMS signal to the chiller for Current limiting during a generator run. ie. set current limit at 70% so as to not stall the genie.
If I am not mistaken their is a phase reversal relay on this machine, it also has a programmable voltage input ie set it for 380,400,415 vac(set in techview). and i think it is also a transformer tap issue, 380-415 which ties in with the phase reversal relay. I would have to check my IOM to be sure.
The HP switch ties in with motor protection.
I have seen a few of these with the emergency stop switch field wired wrong.
make sure genie output is same as utility coming in.

[centrifs]

Their should be a large CT on 3 phase coming into isolator called 6T10. It has 2 terms K&L that feeds relay 1K4, which in turn is an input to modue A6-1 term 3&4 thru field wiring and 6S3 switch (Stop manual reset switch). Check for loose connections on all these and resistance on the field wiring.. Let me know if that helps

[THE WOMBAT]

Hi Centrifs

Found the problem with the voltage detector on the wiring system, supply voltage was just above the cut out limit. all sorted nice one mate

On the back of my disscovery of chiller staging control issuse this is my conclusion report to the client.



Gents
On Saturday while the generators where running i noticed that the chillers would start up after 15 to 20 mins after the generators started.
Found that when the building is on genny the bms enables the chillers when the return building temp is 10*C.
I then discovers that the chiller internal setpoint never changes from 5*C (this is set low to overcome the loss of the undersized mixing header during summer loads. )
When the building return temp hits 10*c the chillers are enable on both south and north, still with there internal setpoint at 5*C.
This causes the chillers to see a 5K diff and rising. Then all the compressors start up on full load, a total load slug of 580A between 2 units onto the generators.
The chillers continue to run for about 20mins then shut down on the bms 10*c return temp, and the process repeats itself.
In summer during a blackout the chillers aren't allowed to run continuously and the building water has been known to hit 16*c plus, also peak and dive during the cycling of chillers by the bms. This isn't good for the chillers, they should be allowed to control on there own logic
The knock on effects of chilled water temperature ramping: 1. VAV AHU's cooling demand/capacity hunting
2. Supply air temp rise.
3. Speed increase to supply and extract fans, because of trox demand for cooling (more air flow)
4. Entire building cooling systems drive to 100% demand (zero bypass on 3 port valves,)
5. Temperatures quickly elevate in office supplies, as the AHUs supply more hot air under trox
demanding more air flow rate.
6. Site wide load increase on generators because of AHU fans, adding 150kw to site load

This chain of events was ALSO happening on the Dorset chillers last summer. This was rectified through staging control adjustments on the YORK BMS out-station. A second chiller was brought on-line to run continuously, effectively part load sharing at 70% each. The second chiller was need to run continuously to obtain better mixing in the low loss header. The chillers where then allowed to run on there own logic control




Re-commissioning of the Satellite York BMS control points will be to these settings:
CURRENT SETTINGS
Normal bms setpoint (out-station in satellite) 7*C
BMS setpoint during generator operation 10*C
Actual Chiller setpoint 5*C (this never changes)

RE-COMMISSIONED SETTINGS
Normal BMS setpoint 5*C
BMS setpoint during generator operation 5*C
Chiller will remain at 5*C
This will allow the chillers to start up instantly when the power is restored by the generators (typical chiller restart time 1 min after power reinstated)
Building water temp will be brought back under control, and WILL NOT stop the chiller ! The chiller will unload itself until condition of loading is stabilized
This will stop the BMS from start / stopping the chillers and reduce overall building peaking load on generators and maintain stable office enviroments
Cheers

Thanks for all ya help gents

[centrifs]

Well done, good luck with it.

[JohnSamsa]

Check that the CT's sensing current and phases on the micro board are all wired into the board the same way. We had one where the CT's were wired (White - Black), (White - Black), (Black - White) This was a 4160 Volt instance. The unit operated fine for a few years like this, then all of a sudden started acting up with an occasional Phase reversal failure. We switched the wiring to match the other two CT's and whala, no more problem.

Another suggestion is to make sure all load through the CT's are heading in the same direction. ie: from the source through the CT to the load. IF a lead passes through in reverse direction correct. You may have several leads passing through a single CT for a total current draw. I found one years ago that challenged many of techs from many a firms.

In situations like this my favorite saying is "Keep it simple!"

Get'er Done!

[JohnSamsa]

Excuse me it looks like situation is under control. Well it was fun to post!

[THE WOMBAT]

Yeah John will look into that one, and check the other 3 units.

what your describing is the same instance we had here. They ran fine for about 2 years now acting up.

I will check the CT's for there correct directional path and wiring terminations.

I have to seen in the past multi units wired differant, must of been when someone had a little too much beer the night before work :confused:

[sondavid75]

let's solve this matter . please you inspect three spare parts .
CT. 3 small transformer, and board modul starter.
Thanks

[Toosh]

let's solve this matter . please you inspect three spare parts .
CT. 3 small transformer, and board modul starter.
Thanks

Hi This thread is over a year old and the problem has been rectified
:eek:

[Chillermech123]

Hi This thread is over a year old and the problem has been rectified
:eek:
Glad its solved. Trane has a bulliten out on this diagnostic.