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### How to Read and Understand Industrial Electrical Schematics

07/05/2012 1:26 AM

Hi all,

this is my first post on this forum.

I have just recently seen an electrical schematic for the first time and i was actually scared when i flipped through the pages.

I have had no prior experience regarding this as I am a fresh engineering graduate.

So i would like to know how to read the drawings as I need to learn many of them.

Are there any online videos or books regarding this?

I am not able to get much help from seniors so thats why I am asking in this forum.

I am trying to understand the Autochangeover scheme for a 3I/C:1B:C scheme(third I/C is from a DG for Emergency)

Pathfinder Tags: drawings electrical help schematics scheme
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Guru

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#1

### Re: How to Read and Understand Industrial Electrical Schematics

07/05/2012 1:40 AM

Just search for "schematic tutorials" or "understanding schematics".

You'll find things like this: Tutorial - How to Read a Schematic

There's many more to find.

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#2

### Re: How to Read and Understand Industrial Electrical Schematics

07/05/2012 1:47 AM

I saw it but what i want isn't in that.

That was just the utmost basics...

I am trying to figure out the control circuits of the 3 incomer:1 bus coupler schematic.

Specifically the closing circuit,tripping circuit,auto-changeover circuit

Its made by L&T and has 29 pages...

Guru

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#3

### Re: How to Read and Understand Industrial Electrical Schematics

07/05/2012 1:53 AM

Good luck.

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#4

### Re: How to Read and Understand Industrial Electrical Schematics

07/05/2012 2:11 AM

can i get help regarding the closing circuit,tripping circuit and autochangeover scheme?

Guru

Join Date: Sep 2007
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#5

### Re: How to Read and Understand Industrial Electrical Schematics

07/05/2012 2:27 AM

if your schematic has component names, you can look them up at suppliers, like RS or Alibaba, usually you can download the specifications there, which explains the component, from symbol to electrical characteristics.

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#6

### Re: How to Read and Understand Industrial Electrical Schematics

07/05/2012 2:30 AM

it has component names only like VAGM-11,CDG,SKE-11

i found out what these components are for but i am not able to understand the logic of the circuits

Guru

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#8

### Re: How to Read and Understand Industrial Electrical Schematics

07/05/2012 3:12 AM

The purpose of a drawing is to communicate. If the symbology is abstruse then the originator of the drawing has failed to communicate.

Go back to the originator of the drawing and ask for an explanation of the content.

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#9

### Re: How to Read and Understand Industrial Electrical Schematics

07/05/2012 3:45 AM

I don't think the problem lies with the originator of the drawing.

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Guru

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#12

### Re: How to Read and Understand Industrial Electrical Schematics

07/05/2012 6:25 AM

Just oiling the bearings...

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#14

### Re: How to Read and Understand Industrial Electrical Schematics

07/05/2012 9:02 AM

You may look for the write-up on the interlock logics envisaged in the technical specification/contract of the relevant project.

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Guru

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#7

### Re: How to Read and Understand Industrial Electrical Schematics

07/05/2012 3:11 AM

You could contact Larsen & Toubro training center for more education on the equipment.

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Guru

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#23

### Re: How to Read and Understand Industrial Electrical Schematics

07/08/2012 2:54 AM

Yes! Mr. Rao! I am from the L & T's Training Centre at Coonoor and we do conduct a training programme on Design of Control Circuits. You may enrol for the same.

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#24

### Re: How to Read and Understand Industrial Electrical Schematics

07/09/2012 1:28 AM

i will ask my boss and contact you at the earliest regarding the same..

thanks!

Guru

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#10

### Re: How to Read and Understand Industrial Electrical Schematics

07/05/2012 4:53 AM

Why don't you try posting the schematics and identify the components and equipment they are controlling....If you start by identifying the process involved, and what has to be done, then it's much easier to find the control components and how they work in relationship to one another.....Then you can concentrate on one step at a time...

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#11

### Re: How to Read and Understand Industrial Electrical Schematics

07/05/2012 5:01 AM

its a 29 page drawing...

and i dont see any option here to upload images

Guru

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#13

### Re: How to Read and Understand Industrial Electrical Schematics

07/05/2012 7:31 AM

Use the insert/edit image button under Reply to Forum Thread. It looks like a green camera with a flashbulb on the top, only no-one recognises the symbol these days as it is difficult to tell the difference in appearance between a camera, a telephone and a personal spirit level.

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Guru

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#15

### Re: How to Read and Understand Industrial Electrical Schematics

07/05/2012 9:21 AM

Dear Chinnarao,

First thing to do is to stop getting scared. Reading electrical drawing is not any thing that some one can teach on line. It is real practical job unlike tutorial to be injected in your head or memorised. It is learned by by actually understanding the concept. These are not taught in engineering college syllabus.

First try to read simple drawings to start with. Learn or understand the symbols used which are normally common. A child does not start to eat a full meal first, instead with simple food they can eat with out chewing and digest. They have to learn it by eating and not watching the video on line.

Instead starting with complicated drawings first start with a simple direct on line starter,then go to star delta starter and so on. Understand the concept of a circuit. Once you understand the concept you can read any complicated drawing. This I am telling from my on experience. There is no short cuts in learning it has to come the hard work.Way back in 1963 when I came out of college I also felt the same way as you feel now when I was directly posted as electrical maintenance in charge of a large production shop floor, with out even a day's training because it was war time and no one had time to teach you. But the the breakdowns have to be attended on priority.So had to work all day and learn all night . That is how one learn it. Those days there was no organised training facility in India.

Now it is much easier in India. You can get ready made practical training packages by training facility provided by reputed organisations like L&T . If you are employed ask your employer to arrange for an induction training. So learn the hard way. Best of luck.

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#18

### Re: How to Read and Understand Industrial Electrical Schematics

07/06/2012 3:03 AM

wow...

you have taught me so much in so little words....

thanks alot abe...

i will start from the basics and then go up...

thanks alot to all you guys for the help

Guru

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#16

### Re: How to Read and Understand Industrial Electrical Schematics

07/05/2012 8:29 PM

If you really cannot find an explanation on certain symbols, zoom in on a symbol, press Ctrl+ Prnt Scr button open MS paint, push paste, the whole copied screen should d be visible in MS paint, cut out the symbol, clear screen, paste symbol and save it as JPG.

Then use the green camera button above, to put the pictures here.

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#17

### Re: How to Read and Understand Industrial Electrical Schematics

07/05/2012 11:12 PM

I agree with Mr Abraham . Reading and understanding of electrical schematics can not be taught in forums. To start with 29 page drawing with under voltage relays and synchronising relays are too much to understand. Please see some simpler drawings like motor feeder circuit,incomer of panel circuit etc Broadly any schematic diagram will have Power circuit,metering circuits,control circuits etc Please try to understand the devices mentioned in the drawing and its purpose then only it will be easy to understand If you want further please contact over phone , it can be briefly explained

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#19

### Re: How to Read and Understand Industrial Electrical Schematics

07/06/2012 3:04 AM

thanks for the help mr ramesh... i will contact you

can i have ur mobile number?

or ur mail id?

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#20

### Re: How to Read and Understand Industrial Electrical Schematics

07/06/2012 3:16 AM

CR4 administration do not permit to reveal explicit information about individuals Please get permission to give my contact details

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#21

### Re: How to Read and Understand Industrial Electrical Schematics

07/06/2012 3:55 AM

ok sure!

Guru

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#22

### Re: How to Read and Understand Industrial Electrical Schematics

07/07/2012 2:58 AM

You can click on the person's user name for a private email to them.

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#25

### Re: How to Read and Understand Industrial Electrical Schematics

07/09/2012 1:35 AM

Hi all...

I found this diagram of a control circuit for a 3 phase induction motor...

can anyone explain to me how the circuit switches from star to delta?

i can't find any timer device in the diagram...

the original link for this file is here

i would be very grateful for your help

Guru

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#28

### Re: How to Read and Understand Industrial Electrical Schematics

07/09/2012 9:48 AM

Hi! The said drawings were made by me for a training programme to electrical engineers from Afghanisthan organised thro IEEMA, New Delhi. You have at last come to the original author. As I said, it is better explained in person rather than thro aforum or mail. Pl. register for one of our training programmes and meet us at our place. We will try to clarify all your doubts on control circuits.

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#29

### Re: How to Read and Understand Industrial Electrical Schematics

07/10/2012 6:11 AM

oh wow...!

haha...

i would surely attend your programme if not for the fact that i am the only Graduate Engg Trainee in my dept.

a lot of office issues are present here...and it would be very difficult for them to send me for a training...

Btw i work in petronet lng @dahej

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#26

### Re: How to Read and Understand Industrial Electrical Schematics

07/09/2012 4:40 AM
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#27

### Re: How to Read and Understand Industrial Electrical Schematics

07/09/2012 5:04 AM

i have read it but what lines should i trace?

i understood the power circuit connection...

but i dont understand the control circuit operation

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#30

### Re: How to Read and Understand Industrial Electrical Schematics

07/15/2012 2:35 AM

I have just completed my vocational training at L&T(pre final year,B.tech) and came with the same problem.U must be talking about EME MCC(or some another 415V MCC). The best thing to do is to ask ur guide and other seniors(just with some more experience than you), and spend some more time with the L&T circuit schematic.

All the best for your future. :)

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