Discuss From Voltage Source to the Machine in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

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amantelnar

I have a project assigned to me, i.e. to calculate/compute the wire size, length, put a motor control in a Plastic Machine.

I have some sources available, but still I want to know from the best people of this Forum.
Please assist me on how to compute the wire size, wire type, type of controls I will be using for the machine.

Thanks for your help. God Bless!


Amantech
 
Well as a start this is Homework so review your notes, second you have given us absolutely no relevant info to even calculate your query so really thinking about this you are either not understanding what you have been taught and thus need to be asking a very different question, the fact you haven't supplied the relevant info leads me to believe you are out of your comfort zone or don't understand how to do it. Show your working out first and then we will correct you on your cable calcs if needed.
 
To Identify the Wire Size, I have the following value available:

Voltage Requirement : 380 VAC
Electrothermal Furance Power : 15 KWatts
Vacuum-Pump Power : 1.1 KWatts
Length(distance from the power source) : 10 meters (32.8 feet)

Here's my Calculation/Computation:

Ampere = Power/voltage

= (15KW+1.1KW)/380

= 16.1 KW/380

= 16,100 watts / 380

I = 42.4 Amperes


For the Wire Size, I used this link: Amps and Wire Gauge - 12V Circuit


The rows above for Current is = 42.4 A I used the 50 A Column
The column at the left side, the distance is 32.8 meter = I used the 40 feet

SO, the intersection of 50 A and 40 feet is = # 2 AWG


I'm not pretty sure if my calculation is correct. Please enlighten me. Thanks in Advance!
 
you need an amarican forum, in the UK, we use metric cable sizes and so can't help with awg sizes.
 
You are a bit lost in your calculations there, you have a 3 phase power supply and resistive and inductive loads.
You have used a 12V table for looking up the current.
You want to know the power factor of the motor (if this is covered in what you are studying) to find the actual power consumed.
Then you want to calculate the current for each phase, assuming it is a balanced load.
Then find tables of current carrying capacity and volt drop for the cable type you will be using.
Apply your local limits on volt drop and select a suitable cable then compare the current carrying capacity (in three phase) to see if it complies.
 
As Richard has kindly pointed out you are seemingly lacking in knowledge of key thingd which will allow you to calculate this, I ask if this project is real world or theoretical?. You can't simply convert the KW rating of a motor using ohms law as it seems you are doing, you cant simply google cable sizes off the internet as these are just distance per csa of cable and load related.... you need to apply many factors such as installation method, cable type, grouping, temp etc etc . Google is a wonderful tool but these tables are a guide for current carrying capacity after you have applied all relevant de-rating factors and not for allowing you to calculate a cable size by using basic ohms law and picking from a table, it doesn't work like that.... you need to get an electrician or electrical engineer to overview the project and to correctly calculate the cable size. As you are not UK based our own guidelines, tabulated values etc may differ as well as regulations so even with all the relevant info supplied we would only be able to give you a answer based on our BS standards which may contravene your own local regulations.
Don't take this the wrong way but from the general response and initial posting its clear you are not educated and competent to do this and to be honest we don't really run a free 'do all the calculations' for me service, we are here to aid those who just need a light nudge or small correction not for those who are clearly delving into things they have no basic understanding of.
 
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The other surprising thing here, is that the Philippines no longer use AWG, it's now Metric like the rest of the world!! lol!! Not totally sure, but as far as i know, only the USA still use the AWG, and sooner or later they too will have to go over to the Metric international standard. Even Canada no longer use AWG conductors, ...still use those crap American 120/240V style sockets and plug tops though!! lol!!
 
I just sensed that all of you who replied were really non-sense. Logic is very simple, truth & truth = truth, or truth + false = truth...I'm after the good answer and not your comment of who am I or what I've done was wrong. I hope you know the word "enlightenment" all your answers are non-sense. If you don't want to help, then don't ever bother to reply... you are not helping at all!!!
 
Don't take offense but your the one that asked a question and supplied only part of the info required to work out a cable calculation, when asked to show your working out you obliged but showed a formula of basic ohms law, you can apply that to the motor as a straight equation to get a current demand.
You haven't told us the front end device you wish to use, the cable, the installation method you have chosen, the temp' which may or may not be a large factor as its supplying a plastics machine if it heats the plastic up ...in essence we can't possibly know what would be the correct cable size until you supply all the info to calculate it... and if you think all this is wishy washy talk then im out of here!! The very fact you seem to think you can just do a simple equation is worrying if this is a real project... if its just homework then you should have suitable notes to refer to... the de-rating factors applied to cables ae vital to ensure they meet the requirements and don't become a safety or fire hazard. We are not over complicating matters this is how our British standards work and must be adhered to to comply with BS7671. You will need to follow your own local standards which may differ to calculate the cable size.

You also ask us for the control wiring type and size but we have absolutely zero on the control system we would need a spec, what kind of containment your using what thermal effect the elements if present may have on the cables as im sure you'll have some kind of temp' monitoring system ...the list goes on so if your serious about the question you been asked please supply the required info we have requested or don't expect any useful replies.
 
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