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Power-User

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Terminal Marking of CT

08/11/2011 12:57 PM

c.ts are marked often with letters k,l. what does these mean and which side i.e. k or l should be towards load and which side towards source. also what does the deisgnation like "0.5 M10" and "5 P10" mean in the specifications of C.T rating.? are they related to saturation or turn ratio error of the CT ?

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#1

Re: Terminal Marking of CT

08/11/2011 1:21 PM

Isn't this covered in your text book?

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#2
In reply to #1

Re: Terminal Marking of CT

08/11/2011 1:41 PM

He doesn't have any!

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#3
In reply to #2

Re: Terminal Marking of CT

08/11/2011 2:00 PM

He's got CR4, he doesn't need any text books.

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#13
In reply to #3

Re: Terminal Marking of CT

08/11/2011 4:59 PM

Just a friendly reminder, I think too often you over do your habit of NOT being nice to people less eloquent or knowledgable than you .

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#14
In reply to #13

Re: Terminal Marking of CT

08/11/2011 5:13 PM

And I think it leads to some people not wanting to post on these forums b/c they don't want to put up with being belittled for asking a question that some may consider a no brainer, even if the resources aren't easily available elsewhere.

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#15
In reply to #14

Re: Terminal Marking of CT

08/11/2011 6:45 PM

Carry on then,

Cheers.

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Guru

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#9
In reply to #1

Re: Terminal Marking of CT

08/11/2011 4:36 PM

This is certainly not covered in text book. Text book only give basic principles and theory, this is specific question related to the trade . IMHO, there is legitimate ground for the question, don't you think so?

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#4

Re: Terminal Marking of CT

08/11/2011 2:52 PM

Can you clarify the question? I'm failing to understand it.

Typically, when using any acronyms, the first time they are used, they need to be spelled out.

CT = Clock Tower?

Cooperate Turd?

Cowardly Turtle?

Cap & Tax?

Cascading Topography?

LOL.. I could go on forever with this nonsense, but I'll save myself some of the embarrassment.

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#5

Re: Terminal Marking of CT

08/11/2011 3:06 PM

I'm gonna assume the guy is a new grad just starting out at an engineering firm where he has had no proper schooling on the symbology of real electrical equipment like C.T.'s, V.T.'s, GCB's, etc.... Just resistors, caps, inductors, transistors, diodes... Like most all electrical engineers suffer from. If it were in his textbooks, I'd assume he could find it, not that he is too lazy to find it. But rather than just copying what other drawings have done, he's trying to figure out why.

I'm sorry that I do not know the answer to your question coolyaar, but maybe if the above guys would try to help the new guy, rather than make their jokes about how easy something is that they learned decades ago, you would already have the answer.

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#7
In reply to #5

Re: Terminal Marking of CT

08/11/2011 3:25 PM

Well said Pete!

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#6

Re: Terminal Marking of CT

08/11/2011 3:08 PM

i am referring to current transformers. if some one is not interested in reply to a post, he should not read it instead of passing rubbish comments like LOL , OT , etc.knowledge is meant for sharing .

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#8

Re: Terminal Marking of CT

08/11/2011 4:21 PM

i have newly joined an R&D firm , but am realy screwed off by the fact that those engineering textbooks gave me nothing for the practical field job.i am in the very start of my job and am engaged in multifields i.e. genset O&M , UPS system handling , switchgear O&M , and above all our own 500 KV grid station. this has diversified my mind and i am a guy with engineering textbooks in my mind that contained just rubbish mathematics and useless formulas.

this forum has helped me a lot and great guys are here for help except a few jokers.

but i really admire the guy on eng-tips.com. they will even answer you how 1+1 is equal to 2 . they know that only those ask questions who know about something and the loosers just laugh.

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#10
In reply to #8

Re: Terminal Marking of CT

08/11/2011 4:44 PM

Don't be frustrated, your full answer is simply here:

For CT (Current Transformer) marking:

The CT markings are: K = P1 (Primary current in), L = P2 (Primary current out), k = S1 (secondary current out), l = S2 (secondary current in)

See this link: http://www.electricmeters.co.uk/pdf/CT-Wiring%20DiagramAndInstructions.pdf

For "0.5 M10" and "5 P10":

See this thread: http://cr4.globalspec.com/thread/43440/CT-Classes (comment # 1)

Hope you got helped.

(Note: I agree, this information is not available in the electrical engineering text book)

- MS

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#19
In reply to #10

Re: Terminal Marking of CT

08/12/2011 4:42 AM

Hi Msamad, I would have to agre with you, you get my GA.

But do you know what really hacks me off!

Globally we have a brain drain, Companies are not taking on apprentices or training people. We should be encouraging young people to look at working in the electrical field, not by negative comments (not you) that have been said in this forum.

We should help these young minds and nurture them, not scare or shame them!

We should encourage them so that they can reach their full potential and have a better understanding, that they can also pass on to the next generation.

After all they are going to look after us, when we cannot look after ourselves.

Cheers

Joe

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#11
In reply to #8

Re: Terminal Marking of CT

08/11/2011 4:47 PM

Hey now... I may be a Joker, but rooted in my nonsense was a bit of non-nonsense. I'm a lowly a mechanical guy, with a 2 year electrical degree (just enough to know that I don't know enough). I honestly didn't know what "CT" meant, I could have guessed all day, with no success, as the acronym "CT" could literally mean hundreds of things.

My point is any time you use an acronym, spell it out the first time it's used, then go ahead an use i the rest of the time, but I have seen so many posts that read something like:

"How to disable the KP on a DSS without knowing the JW, and please explain where IPC is applicable?"

I think you can all agree that that could mean anything or nothing at all. It's just a pet peeve of mine

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#16
In reply to #8

Re: Terminal Marking of CT

08/11/2011 8:53 PM

coolyaar,

You should understand that those of us long time denizens of this forum have seen COUNTLESS students attempt to get us to do their homework for them. Not only is this a waste of time, but it teaches them nothing. Or as I like to put it, they must be studying how to be managers, not engineers, because all they learn is how to take credit for the work and expertise of others.

Many of your questions have been of such a basic nature that they appear to be exactly like the student postings we see so often. If, as you claim, you are not a student then we owe you a sincere appology. You have it from me on those grounds.

On the other hand you could just as easily be a student not above lying about your circumstances in order to elicit sympathy. We have no way of knowing.

As to the other forum, that is much more rigorously moderated and the reason you do not see as much acrymony there is because they very unceremoniously delete all student postings and any records of such, then the students are banned for life from ever participating again. But believe me, when students post there they are lamblasted just as vehimently, if not more, before the moderators quickly delete the entire thread. Had you been posting these kinds of questions there in the same volume as I've seen here, you would have been banned by now. I know, because I would have requested it! Maybe it's draconian, but those of us who VOLUNTEER our time and experience in these forums do not like being taken advantage of.

Just a suggestion, a little humility on your part would go a long way toward repairing the relationship here. Speaking only for myself I'm willing to forgive and forget and move on, but I can't speak for some of the other curmudgeons in here, we are a crabby bunch sometimes. I only ask that you maybe do some of your own investigative research first, then ask us for clarifications after showing that you got stuck on something that isn't obvious. This thread was actually a good example of that, I myself had no idea what those meant as they appear to be IEC related and I am in North America (something else to consider when posting questions, engineering standards differ all over the world).

Don't give up on us and we won't give up on you.

Soapbox rant complete.

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#12

Re: Terminal Marking of CT

08/11/2011 4:53 PM

Bye, bye.


The Joker on the cover of Batman: The Man Who Laughs.
Art by Doug Mahnke

Publication information

Publisher

DC Comics

First appearance

Batman #1 (Spring 1940)[1]

Created by

Jerry Robinson (concept)
Bill Finger
Bob Kane

In-story information
Team affiliations

Injustice Gang
Injustice League
The Society
Club of Villains

Notable aliases

Red Hood[2]

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#17

Re: Terminal Marking of CT

08/11/2011 10:09 PM

i agree that many things may not be in the text books, but are surely available on the web, for example....

http://www.kappaelectricals.com/technical.html#current

An extract from that website....

Where there is a will...there is Google

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#18

Re: Terminal Marking of CT

08/12/2011 3:05 AM

There is a ppt file here which gives quite a bit of information on CTs.

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#20

Re: Terminal Marking of CT

08/12/2011 5:17 AM

thanks a lot for encouraging me and replying to my posts. i have recently joined this forum ( probably in this august ) and do not know that questions are posted by students for their assignment soultions. but to clarify my status let me give you refrence of some of my posts :

1: i asked about the colors of indicating lights on HV,MV and LV switchgears . now have you seen any university having such switchgears and studenst asking about them ?

2: the firm where i am has switchgears from siemens, so i asked about the control drawings logic symbols of siemens drawings. i think no student will care about sysmbols used by siemens in their control drawings

3:i asked about reverse power setting of my 300 KVA genset and shared an experience of my friend from cummins engine (maximum 20% settings ). will any university student know about cummins engines and their settings ?

now if any one still has doubt , then he has the right not to read and not to reply to my post. if some one has any information about a forum where there are people asking basic question, then kindly tell me. i will switch over to that forum / website .

regards,

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#21

Re: Terminal Marking of CT

08/12/2011 5:39 AM

I apologize for the question and it 's been 20 years ago that I left school,

and I know how to use a current trafo (CT) but untill now, I don't know what the initials l, k, L and K stand for

Like P stands for Power, and I stands for intensity, m for mass, etc..

What is the meaning of l, k, L, K

Most regards.

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