AIR COOLED CHILLER.

[Eire79]

A.C.C 225KW, 371A F.L.A. on data plate.
PROTECTION;
SCHNIEDER NSX 400A MCCB WITH MICROLOGIC 3.2 TRIPPING UNIT SET @ Io 400A,Ir x1, Isd x4 AS INSTALLED BY CONTRACTORS 6YRS AGO AND CABLE IS 4X 150sq.
Unit has 4 compressor circuits D.O.L via 160 A SIEMENS Gg fuses.
The issue has been 2 no trips on the MCCB during the last week and looking for advise as to the possible cause be it a electrical issue or some mechanical fault in the compressor putting a strain on a compressor circuit starting. I have checked mains cable, all compressors and can not find any issue with them.
I also have put ammeter on incomer which has recorded 260 A per phase with all circuits running but i understand the ampage will be higher on startup,one thing to note is the the unit does not bring in all circuits at once it ramps up over time.
with regard the MCCB i have inspected the terminals and see no heat issue and have recorded a terminal temp of 32 degrees c across all.
Can MCCBs become faulty or the tripping unit or can anyone point to any other issues . Thanks.

 

[Pete999]

A.C.C 225KW, 371A F.L.A. on data plate.
PROTECTION;
SCHNIEDER NSX 400A MCCB WITH MICROLOGIC 3.2 TRIPPING UNIT SET @ Io 400A,Ir x1, Isd x4 AS INSTALLED BY CONTRACTORS 6YRS AGO AND CABLE IS 4X 150sq.
Unit has 4 compressor circuits D.O.L via 160 A SIEMENS Gg fuses.
The issue has been 2 no trips on the MCCB during the last week and looking for advise as to the possible cause be it a electrical issue or some mechanical fault in the compressor putting a strain on a compressor circuit starting. I have checked mains cable, all compressors and can not find any issue with them.
I also have put ammeter on incomer which has recorded 260 A per phase with all circuits running but i understand the ampage will be higher on startup,one thing to note is the the unit does not bring in all circuits at once it ramps up over time.
with regard the MCCB i have inspected the terminals and see no heat issue and have recorded a terminal temp of 32 degrees c across all.
Can MCCBs become faulty or the tripping unit or can anyone point to any other issues . Thanks.

Are the condenser /evap coils blocked ? how often do yo clean these coils? are the filters clean ? could be a fouled Refrigeration cycle

 

[Eire79]

Are the condenser /evap coils blocked ? how often do yo clean these coils? are the filters clean ? could be a fouled Refrigeration cycle

The chiller get serviced on regular intervals, but as you say if any of these are blocked etc will it be intermittant or a constant blockage.
whats the effects ?

 

[Pete999]

The chiller get serviced on regular intervals, but as you say if any of these are blocked etc will it be intermittant or a constant blockage.
whats the effects ?

Chiller will trip out on High or low pressure depending on which items are blocked or dirty, look up the refrigeration cycle on you tube for details\

 

[timbobelfast]

A.C.C 225KW, 371A F.L.A. on data plate.
PROTECTION;
SCHNIEDER NSX 400A MCCB WITH MICROLOGIC 3.2 TRIPPING UNIT SET @ Io 400A,Ir x1, Isd x4 AS INSTALLED BY CONTRACTORS 6YRS AGO AND CABLE IS 4X 150sq.
Unit has 4 compressor circuits D.O.L via 160 A SIEMENS Gg fuses.
The issue has been 2 no trips on the MCCB during the last week and looking for advise as to the possible cause be it a electrical issue or some mechanical fault in the compressor putting a strain on a compressor circuit starting. I have checked mains cable, all compressors and can not find any issue with them.
I also have put ammeter on incomer which has recorded 260 A per phase with all circuits running but i understand the ampage will be higher on startup,one thing to note is the the unit does not bring in all circuits at once it ramps up over time.
with regard the MCCB i have inspected the terminals and see no heat issue and have recorded a terminal temp of 32 degrees c across all.
Can MCCBs become faulty or the tripping unit or can anyone point to any other issues . Thanks.

Can you get me the motor sizes in kw etc, and I can put this design through software for selectivity.

Do you know the duty sequence as well?

I have seen plenty of MCCBs go faulty, Schneider and Eaton.

Any schematics for the set up as well?

Is the skid controlled by PLC? Has anyone tinkered with the logic?

You could try adjusting the lsd to max setting of 8 or 9 in the mean time

 

[Eire79]

Can you get me the motor sizes in kw etc, and I can put this design through software for selectivity.

Do you know the duty sequence as well?

I have seen plenty of MCCBs go faulty, Schneider and Eaton.

Any schematics for the set up as well?

Is the skid controlled by PLC? Has anyone tinkered with the logic?

You could try adjusting the lsd to max setting of 8 or 9 in the mean time

Thanks for that I'll get details for you, that's some set up with software.

 

[Eire79]

Can you get me the motor sizes in kw etc, and I can put this design through software for selectivity.

Do you know the duty sequence as well?

I have seen plenty of MCCBs go faulty, Schneider and Eaton.

Any schematics for the set up as well?

Is the skid controlled by PLC? Has anyone tinkered with the logic?

You could try adjusting the lsd to max setting of 8 or 9 in the mean time

So here are some specs , and images.
4 compressor 40.4 HP 60.3A each
8 fans variable speed at 1.1 kw each.
The chiller is cooling various tanks for production equipment and also A.H.Us for temperature control of rooms, system runs 24/7 via a bms system which is basically monitoring temperatures and controlling pumps to different circuits.

 

[timbobelfast]

OK, thanks for that.

I'll input the loads and see what it looks like.

Has there been any maintenance, eg greasing, filter changes etc?

 

[Eire79]

OK, thanks for that.

I'll input the loads and see what it looks like.

Has there been any maintenance, eg greasing, filter changes etc?

Just general maintenance carried out by external air con contractor, not sure what they check but will have a look at the dockets.

 

[timbobelfast]

Just general maintenance carried out by external air con contractor, not sure what they check but will have a look at the dockets.

Any recent trips with the increase in ambient air temperature?

See attached which is similar to the way the Schneider ACB 'As Found' settings.

If maintenance has been tip top, and there have been recent trips then I would be sticking a power analyser at the upstream device and trend where the spike is occurring.

You could also trying adjusting the lsd setting at the MCCB.

But depending on the type of site or client that it is, will probably require an MOC!

 

[rapparee]

Any recent trips with the increase in ambient air temperature?

See attached which is similar to the way the Schneider ACB 'As Found' settings.

If maintenance has been tip top, and there have been recent trips then I would be sticking a power analyser at the upstream device and trend where the spike is occurring.

You could also trying adjusting the lsd setting at the MCCB.

But depending on the type of site or client that it is, will probably require an MOC!






View attachment 87779

So in my ignorance, I had to Google MOC

Apparently it means masculine of centre

Something about butch lesbians ?

 

[timbobelfast]

So in my ignorance, I had to Google MOC

Apparently it means masculine of centre

Something about butch lesbians ?

LOL, close!

Management of change. In this case proposing to change the characteristics of a MCCB

 

[marconi]

The trips could be due to other items of electrical equipment starting. Anything new installed recently?