# Troubleshooting the MCC



## eric7379 (Jan 5, 2010)

dronai said:


> If there is a problem, all I have to do is trace the input from the aux


Soooo.....what's the problem??

Is this for your new job? I can understand it being a little hairy in a situation like this where you don't know where everything is and just hope that the person that labeled everything wasn't a nutcase. 

I have to do this all the time, but in my situation, everything (well, mostly everything) is labeled. If there are different racks or remote I/O's scattered throughout the machine, every enclosure is labeled with what the rack number is or what part of the machine the enclosure is for. Sort of the same thing with the electrical prints.


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## dronai (Apr 11, 2011)

eric7379 said:


> Soooo.....what's the problem??
> 
> Is this for your new job? I can understand it being a little hairy in a situation like this where you don't know where everything is and just hope that the person that labeled everything wasn't a nutcase.
> 
> I have to do this all the time, but in my situation, everything (well, mostly everything) is labeled. If there are different racks or remote I/O's scattered throughout the machine, every enclosure is labeled with what the rack number is or what part of the machine the enclosure is for. Sort of the same thing with the electrical prints.


 
I'm long time electrician, but new to controls. But what I'm seeing is, that once you know one MCC in my place, the components are pretty much the same and repeat. times 92 cabinets.

Yes, the wires are all numbered perfectly, and panels labeled. Prints are in every cabinet, and document everything to the tee.

Looks intimidating at first till your familiar with the components.


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## MDShunk (Jan 7, 2007)

So why did you take pics of the Ethernet modules in the PLC rack?


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## Frank Mc (Nov 7, 2010)

MDShunk said:


> So why did you take pics of the Ethernet modules in the PLC rack?


I thought they were profibus modules...?..?

Frank


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## MDShunk (Jan 7, 2007)

Frank Mc said:


> I thought they were profibus modules...?..?
> 
> Frank


They could be _anything_bus or _anything_net and my question would still mostly be the same. I'm not super familiar with Seimens stuff the recognize the particular type of network module they are. I'm more of an A-B guy.


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## eric7379 (Jan 5, 2010)

dronai said:


> I'm long time electrician, but new to controls. But what I'm seeing is, that once you know one MCC in my place, the components are pretty much the same and repeat. times 92 cabinets.
> 
> Yes, the wires are all numbered perfectly, and panels labeled. Prints are in every cabinet, and document everything to the tee.
> 
> Looks intimidating at first till your familiar with the components.


In this case, I certainly understand why it looks intimidating if you are not at all familiar with controls, especially at a new job. 

Is the whole place on Siemens PLC's, or is there a mix of a few different types?


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## nolabama (Oct 3, 2007)

It will be a learning curve, but you will get the hang of it. Or not and leave.


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## Wireman191 (Aug 28, 2011)

Start at the beging of the problem ckt, fuse may be the problem. If thats not the problem move to the middle of the control ckt, if you have no power there then you know its upstream from that spot. Best way Ive found for finding issues. 
Check all E-stops, We had to install lights above all the E-stops at one place because the lady's wanted a break so one of them would just hit the E-stop.:laughing:


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## nolabama (Oct 3, 2007)

Wireman191 said:


> Start at the beging of the problem ckt, fuse may be the problem. If thats not the problem move to the middle of the control ckt, if you have no power there then you know its upstream from that spot. Best way Ive found for finding issues.
> Check all E-stops, We had to install lights above all the E-stops at one place because the lady's wanted a break so one of them would just hit the E-stop.:laughing:


Checking those breakers will keep you from looking like an idiot. I was troubleshooting a brake motor, so I thought....


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## Wireman191 (Aug 28, 2011)

nolabama said:


> Checking those breakers will keep you from looking like an idiot. I was troubleshooting a brake motor, so I thought....


 Control fuses are typically smaller then the breaker, thats why I would start there. No power coming through the fuse, you pretty much know its the fuse or the breaker.:thumbsup:


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## buddhakii (Jan 13, 2011)

Pretty simple to troubleshoot the newer mcc. Older installations can be time consuming because you have to trace everything. If the motor is not starting as said before make sure you have control power. If you do have voltage make sure it's getting a start command from the plc. If not check the proper plc output to make sure it is on. If all the lights on the plc are dead check the control fuse in the plc cabinet. If you have the proper start command at the mcc and nothing is happening check the coil on the starter. It all is pretty simple once you get the hang of it. Escpecially if you are just working in this one plant as a maintenance person and can learn the system inside and out.


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## dronai (Apr 11, 2011)

eric7379 said:


> In this case, I certainly understand why it looks intimidating if you are not at all familiar with controls, especially at a new job.
> 
> Is the whole place on Siemens PLC's, or is there a mix of a few different types?


 *All Siemans*



nolabama said:


> It will be a learning curve, but you will get the hang of it. Or not and leave.


 *Yep, Problem will be time to have the belts down, and find, and fix fast.*



Wireman191 said:


> Start at the beging of the problem ckt, fuse may be the problem. If thats not the problem move to the middle of the control ckt, if you have no power there then you know its upstream from that spot. Best way Ive found for finding issues.
> Check all E-stops, We had to install lights above all the E-stops at one place because the lady's wanted a break so one of them would just hit the E-stop.:laughing:


*Have to get familiar*

*Everything reports back to control via the PLC. But learning the links in the chain, from the disco, which also has an aux, all stop start stations also have an aux reporting back to the I/O cards.*

*There is probably a simple method I can use after I know the system better.*

*In general building wiring, I can locate a problem and isolate, and repair pretty fast. This is just new territory for me.*


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## dronai (Apr 11, 2011)

MDShunk said:


> So why did you take pics of the Ethernet modules in the PLC rack?


* Why not  Maybe you can help me ID all communication wiring. The PLC's have what looks like (Large Purple jacketed) Data lines. **small orange* *colored fiber optic wires ? and small purple wires that look like their ethernet ?* *The same larger purple cables are running through all the VFD's *



Frank Mc said:


> I thought they were profibus modules...?..?
> 
> Frank


 
*I found the only 120V panel that read Profi-Bus Optical Network*
*Panel 2 OLMZ 120V 1 phase I was thinking maybe it's the fiber optic network ?*


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## dronai (Apr 11, 2011)

*Fusing*

Looks like 3 control transformers per cabinet. 

I would think testing from the failure back to the MCC, and seeing if the I/O is lighting. Then test power to the Overloads, then starters, and if the coils are pulling in. Next the control transformer fusing. Am I right in the sequence ?

The cabinets would still have power to all the rest of the 10 -15 starters, so I know it's a control issue.

If it's a PLC issue, then it would be testing to see if the I/O is working or not. Possibly a bad card. Am I right ? 

More pictures


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## dronai (Apr 11, 2011)

buddhakii said:


> Pretty simple to troubleshoot the newer mcc. Older installations can be time consuming because you have to trace everything. If the motor is not starting as said before make sure you have control power. If you do have voltage make sure it's getting a start command from the plc. If not check the proper plc output to make sure it is on. If all the lights on the plc are dead check the control fuse in the plc cabinet. If you have the proper start command at the mcc and nothing is happening check the coil on the starter. It all is pretty simple once you get the hang of it. Escpecially if you are just working in this one plant as a maintenance person and can learn the system inside and out.


 
I didn't see this post ! :thumbsup: That is pretty much what I listed above in my previous post, except I started from the motor, to the disco, and then back.

My shift is understaffed, There is an Industrial electrician on the graveyard shift, who is really knowledgable.
But we only hook up for about an hour between shifts overlaps


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## Big John (May 23, 2010)

dronai said:


> ...Yes, the wires are all numbered perfectly, and panels labeled. Prints are in every cabinet, and document everything to the tee....


 Jesus, you're lucky.

-John


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## nolabama (Oct 3, 2007)

Big John said:


> Jesus, you're lucky.
> 
> -John


I second that.


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## lefleuron (May 22, 2010)

Dronai,

You are going to find out its a 90/10 game. After a while 90 percent of the problems you run into you will know exactly what to do because they are repeat problems.

The other 10 percent may be a challenge. If you are there long enough it will become a 99/1 game. Problem then is remembering the 99.


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## 76nemo (Aug 13, 2008)

dronai,

In a scenario like this, your best place to start is with the machine operator. Before you even read error codes or pull prints, see just what you can get out of the machine operator if one exists. If you have someone onboard that knows all of the sequences, ALWAYS start with them, ALWAYS!!!


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## eric7379 (Jan 5, 2010)

76nemo said:


> dronai,
> 
> In a scenario like this, your best place to start is with the machine operator. Before you even read error codes or pull prints, see just what you can get out of the machine operator if one exists. If you have someone onboard that knows all of the sequences, ALWAYS start with them, ALWAYS!!!


But be prepared for the operator to say "It was like that when I got here" or "I have no idea what happened" only to find out later that they were the cause of the shutdown and they were flat out lying about it because they thought they would get in trouble for it.


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## eric7379 (Jan 5, 2010)

dronai said:


> * Why not  Maybe you can help me ID all communication wiring. The PLC's have what looks like (Large Purple jacketed) Data lines. **small orange* *colored fiber optic wires ? and small purple wires that look like their ethernet ?* *The same larger purple cables are running through all the VFD's *
> 
> 
> 
> ...


The larger purple jacketed cables are the Profibus. Inside the cable is shielding and then 2 wires- green and red. The small orange fiber optic lines are probably for Simolink (I think I spelled it right). 

In our application, Simolink is bascically used for a "perfect" speed reference signal. The are several different machine components and everything is independently driven (no line shaft). Everything has to run at EXACTLY the same speed. The operators can adjust the gain on the operating panel to control tensions within the process. 

You might also have green colored cables going to all of the drives. Those cables are the encoder cables. 

In our application, all of the drives operate off of a main DC buss of 700 VDC, supplied by a Siemens AFE (active front end). All of the drives, including the AFE, are water cooled. Sounds crazy, but it does work. Haven't had any water leaks....YET!


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## dronai (Apr 11, 2011)

*Thanks !*



eric7379 said:


> the larger purple jacketed cables are the profibus. Inside the cable is shielding and then 2 wires- green and red. The small orange fiber optic lines are probably for simolink (i think i spelled it right).
> 
> In our application, simolink is bascically used for a "perfect" speed reference signal. The are several different machine components and everything is independently driven (no line shaft). Everything has to run at exactly the same speed. The operators can adjust the gain on the operating panel to control tensions within the process.
> 
> ...


 
*wow !!*


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## nolabama (Oct 3, 2007)

76nemo said:


> dronai,
> 
> In a scenario like this, your best place to start is with the machine operator. Before you even read error codes or pull prints, see just what you can get out of the machine operator if one exists. If you have someone onboard that knows all of the sequences, ALWAYS start with them, ALWAYS!!!



I have an operator, lets call him duma$$, That drives me nuts. Hes really new. When we were having power quality issues, I had him open the drawbridge under genny power to keep the VFDs from faulting. He asks "do I have to close it with the generator?". Wait it gets better..trouble call, bridge stuck open, he had shut the genny off when it was open....so the above advice is crucial to you learning the machines, the sequence of operation is most important for my troubleshooting


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## dronai (Apr 11, 2011)

nolabama said:


> I have an operator, lets call him duma$$, That drives me nuts. Hes really new. When we were having power quality issues, I had him open the drawbridge under genny power to keep the VFDs from faulting. He asks "do I have to close it with the generator?". Wait it gets better..trouble call, bridge stuck open, he had shut the genny off when it was open....so the above advice is crucial to you learning the machines, the sequence of operation is most important for my troubleshooting


 
Did you find out what was causing your power quality issues ?


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## nolabama (Oct 3, 2007)

dronai said:


> Did you find out what was causing your power quality issues ?


Not really, but we fixed it.


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## captkirk (Nov 21, 2007)

Big John said:


> Jesus, you're lucky.
> 
> -John


 I would stop working on my own if i got a job like that now... I love that chit..


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## ce2two (Oct 4, 2008)

I had a operator on a( plating line) tell me what was the exact problem and why , yet my leadman said here is a book, read it :no:i checked all the fuses in the enclosure, one of the control fuses opened, replaced fuse good to go:thumbsup:...never touched the book ever:no:, i had just started with the company ..12 years ago..stayed 2 months..then quit..


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## dronai (Apr 11, 2011)

*Vfd*

In the VFD enclosure, why does the control transformer have two sets of taps ?


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