Control Panels-What the books don't tell you...

Hello guys,

If y'all haven't read the previous post click on the links below:

1)https://electricalmaniacs.blogspot.in/2017/09/electrical-control-panels- interesting.html
2)https://electricalmaniacs.blogspot.in/2017/09/detailed-study-of-electrical-control.html

In the previous post we understood somethings about the control panels sans any book or anything,we just used our basic electrical engineering knowledge.

Now, start by typing "control panel" in google or open the first page of your book and just read the first page.This is what I got.!

"Control panel is a cabinet which contains electrical components to control the motors and equipment".

From this one line only we can understand that control panel is a cabinet that contains electrical equipment (why only electrical equipment,why not mechanical or thermal or some other?/Which electrical equipment?/Why that particular equipment only,what is its importance?)

Then comes..

"A control panel is a flat, often vertical, area where control or monitoring instruments are displayed or it is an enclosed unit that is the part of a system that users can access, as the control panel of a security system (also called control unit).

They are found in factories to monitor and control machines or production lines and in places such as nuclear power plants, ships, aircraft and mainframe computers. Older control panels are most often equipped with push buttons and analog instruments, whereas nowadays in many cases touchscreens are used for monitoring and control purposes".

Questions:

1. Why is the control panel flat or vertical (any specific reason!)?
2. What are control and monitoring equipment?
3. Why are the panels enclosed?
4. Why are they used only in factories,why not in our houses?

One more...

"Electrical control panels control equipment. They include power, control and operator devices that allow an operator to control a piece of equipment. Electrical control panels are used to control every piece of equipment in every industry."

Questions:

1. What are power,control and operator devices?
2. What is the role of operator while using control panels?

These are some of the questions that came into my mind, there may be many more feel free to add them in comments.

These are just the questions and I know most of them are stupid.Most of the times it is those stupid questions,that help us understand the real problem. Try to get some answers to them, in the process of getting answers you will learn a lot more i promise you that.

Also I am not asking you guys any questions , giving you a rather new perspective of understanding a topic(according to me).

Cheers.!!

Keep asking why...

Till the next post...

Detailed study of Electrical Control panels-Part 1

If y'all haven't read the previous post click on the links below:

1)https://electricalmaniacs.blogspot.in/2017/09/electrical-control-panels- interesting.html
2)https://electricalmaniacs.blogspot.in/2017/09/detailed-study-of-electrical-control.html

In a control panel according to my experience, the high voltage stuff is usually kept on the upper part of the panel (this is not a rule though, you can keep them wherever you see fit). For example let's assume that we need some high voltage supply, say 480 V A.C, then it would make a lot of sense to keep the input power source at the top cause one of my reasons is that you obviously need to isolate or keep the electronics (components working at a lower voltage like PLC etc.) far away from the main supply. This is mainly to reduce the electromagnetic interference.

What I believe is that we need to know at least the working of the components that are used in the control panel. We will take all the topics one by one, first one is the Cables/Wires:

• Cables:
  They are one of the most basic components of control panel that are used for the purpose of interconnection.Now cables come in a lots of sizes and other stuff.So utmost care is needed in selection of proper cables for proper application.This looks very simple but if proper size of cable/wire is not selected ,then there will be heating due to which the wire gets damaged and if the wire gets damaged then the equipment connected to it is in the danger of getting damaged , it also could have disastrous circumstances for humans.There also is a lot of wastage of money.So it is important that we use proper cable size.Let's see how can i decide it.
• Before doing that let me first give you some basic info. About the control panels.In the control panels there are basically two kinds of circuits.

1)Power circuit*(contains higher voltage components).

2)Control circuit*(contains electronic and electronics works at much lower voltage level).

*This classification is given just for the sake of understanding this topic, A detailed explanation about both would follow in the later posts.

So, if you think logically both the circuits would have different ratings and would work in different conditions, so obviously the cables/wires used for their interconnection would be different.

Now, basically there are two kinds of wires/cables in a control panel,

1)Power cables (one's that have a higher rating,also called as FIELD DEVICES WIRES)

2)Control cables(used in the control circuit,also known as PANEL WIRES)

Basically the wire size is determined by generally by two basic factors(these are the basic , there are more smaller factors)

1) Current load of the wire.

2) Insulation rating of the wire.

• First make a list about what do you know about your panel.
• In the list ,first of all we should know what kind of load is supposed to be connected to our panel.
• Then what kind of power sources are present : A.C. / D.C. power for 3ph. OR 1 ph. (mostly H.V 3ph. A.C is used ).
• Next is the full load current.
• Then you need to know the circuit breaker size.
• The types of cables(PVC,XLPE,fire proved)
• Installation condition(whether it is underground,overground,trunking,tray or conduit)
• Distance / length of cable run from source to the load.

I think these are the things that you should know before starting building/understanding a panel.

Once you have all those data then we move on to the calculation step for the cable size.

There is a little formula for the calculation:

Ib≤ In ≤ Iz

Ib = Amperage load

In = Circuit breaker size

Iz = Current rating for cable/wire

Using the above formula you can decide the current rating of your wire.There is a whole post on that ,but let's not get into that now first just concentrate on the basics ,then we will get into the design aspect.

Till then stay cool!!

Keep asking why??!

Bye...(till the next post).

Note:Guys if you find something better than this please comment and i will be more than happy to     learn from you.

Thank you.

ELECTRICAL CONTROL PANELS -An interesting perspective ( part 1)

Hello again,

This title must confuse you especially after my first philosophical post (not a big fan of philosophy),but the first post was important for understanding my purpose for writing.This is the first step that i am taking towards educational redemption.

First a little Disclaimer: "I am not an expert or something,i am a student who is trying to share his whatever little knowledge he has with you people.I  may be wrong sometimes,so if i am at any point feel free to comment on it".

The topic that i have chosen is "Control Panels".I basically am an electrical engineer and this interests me so,lets give it a try.The method i am talking about is about asking more and more questions,from something you read or imagine (even better).The first step would be to see it from a visual perspective.Let's take an example picture.
So,what do we see here?. Let's make a firsthand raw impression.

• I see a metallic box in which there are switches,lots of wires,channels on which the components are mounted,switches,circuit breakers,terminal blocks etc.
  

Let's see another picture...

And another one...(they say pictures are the best form of learning )

A big panel..

Let's talk about the various components that we can understand that should be a part of a control panel

1. A metallic box
2. A PCB or panel for mounting .
3. Switches
4. Switch-gear(circuit breakers,relays,fuses etc.)
5. A A.C to D.C converter for the electronics(mostly up to 24 V).
6. Batteries or something(for backup maybe,NOT SURE!)
7. Terminal blocks (for wires termination).
8. Rails on which all the components are mounted.
9. Temperature controller (as control panels are enclosed,so i suppose temperature control becomes necessary).
10. A display (obviously!!).
11. A computer(here it is a PLC to control all these guys).
12. A lot more things i suppose, but these were just firsthand visual observations.
    

First of all let's make some questions for some of the parts...

• What kind of metallic box are used ?why,can't we keep them in open?What kind of protection is it supposed to provide?What standard does it comply to?
• What kind of PCB or panels are used ?Why?
• What kind of switches are used?
  

Let me me interrupt you here,before all this things just sit back and imagine that you want to control something (like something electrical of course) let's take a D.C motor.Now mind you that there is a basic difference between running and controlling.We could plug the motor directly to the supply and it would start running,but alas! controlling it ain't that easy .Now the key to controlling a D.C motor basically is that you need to control it :

• By varying the supply voltage
  
• By varying the flux, and by varying the current through field winding
  
• By varying the armature voltage, and by varying the armature resistance
  

Again this is just the listing of technicalities(so don't ask “how or why?”) our main goal here is to have a rough idea about the components in a control panel.This post is just the part of pre learning experience about control panels.

In the next post we are gonna go into much more detail about the introduction to control panels and also i will be posting the answers to those questions in this post.Also a bunch of new questions are on the way,so stay tuned!!

So long guys!!

Until the next time..

Keep asking why???.

Cheers!.