why the two out of phases is called single phase ??

[Jim Dungar]

You are correct there would very few reasons to create the system you describe in your question 1. However, you might use this if you were feeding multiple residences from a single phase transformer that is configured like your previous figure C.

If there is no phase angle difference between your sources, you can not create a three phase source simply by connecting them in a star/wye or delta configuration. Because the three sources are in phase, there will only be one magnetic flux and therefore only a single phase.

 

[magdyfayad]

i.e : i named only " three single phase voltage sources " if and only if the the tree coils are separated , is not right ??

when these three coils are connected as star or delta then we can not named three single phase voltage sources , but only named three phases power source or three phases current source or also can be named three phases voltage source , is not right or not ??


is there any comment for my final results for for the both two cases ( two hot wires and three hot wires ) at posts 87 , 88 , and 90 ??


note : i found all write " three phase current source or three phase power source " without putting " s " at "phase" and all my statements i put " s " as i said " three phases current source or three phases power source " ,

is there any reason to not putting " s " at "phase" after word three or what ??


thanks

 

[keithkyll]

...is there any reason to not putting " s " at "phase" after word three or what ??


thanks

Improper English. No 's'. It is 3 phase.

 

[magdyfayad]

thanks


but first three is a plural so we must say three apples and also must say three phases , what is the difference ??

second what about my final results ?? , is there any comment for my final results for the both two cases ( two hot wires and three hot wires ) at posts 87 , 88 , and 90 ??

i want you to comment for eash statement separtely to be sure my understanding is correct for for each result

also , you now agree with me as when three coils are connected together as star or delta then we can not be named three single phase voltage sources , and also can not be named three phase voltage sources , and also can not be named three phase power sources , because there is no multi voltage sources , as it is only one voltage source with three phase coductors which means three phase(s) voltage source is not right or not ??

but only named three phase(s) power source or three phase(s) current source or also can be named three phase(s) voltage source , is not right or not ??


thanks

 

[keithkyll]

I will not answer another package of 12 questions. You are asking the same things over and over again.
You need to study. If you would study a generator and how it makes electricity with magnetism, you would understand this. I told you a long time ago that until you understand how a generator works, you will never understand this. We are now at page 7, and you still ask the same questions. You still don't understand.
I will not answer anymore until you post a drawing of a generator and explain how it works.
Go study!

 

[tragically1969]

I got bored about 6 pages ago with the barrage of questions, i applaud your patience for sticking with it for so long !!

 

[magdyfayad]

first : i thank you for your help and for your continue with me

second : yes , i ask the same questions , but the main reason is :


yesterday , you agreed with me at post 54 and said to me :

" You are correct. Also, you get 100% for spelling. Your English grammar is almost perfect! I am impressed "

when i said before that:

" also if i take R ( phase conductor ), S ( phase conductor ) and T ( phase conductor ), - either from star connection or delta connection - and applied R , S , and T to a three phase load , i must say it is three single phase voltage sources - not say three phases voltage source - with three phase conductors or with three hot wires "


but after more posts , i found that is not correct !!

you can read post 75 which is :

" I agree that if you had three separate single phase sources (3X2 wires), you could refer to them as

" three single phase voltage sources "

I thought you were refering a single three phase source (3 wires) in which case you should be saying

" three phase voltage source "


and also you can read post 85 which is :

" That's "three phase", or more correctly, "three voltage sources with their frequency out of phase". Note there are three voltage curves. Got it?

Now, for "three single phase", the three lines would be on the same curve; you would see one line of frequency rather than three. There is no staggering of frequency on a "three single phase" arrangement."

and also you can read post 86 which is :

" 3 phase voltage has (1) set of (3) conductors, like A-B-C.
3 single phase voltages have (3) sets of (2) conductors, like A-B, B-C, C-A or A-C, A-C, and A-C. Notice how the first set can be combined into a 3 phase system (A-B-C), but the second set cannot "



so i want to modify the data which i take from you and to be check for it


there is no doubt i benefit from you at this discussion and all your disccusions with me



and also i thank you again for your help



that is enough for this forum for me and i do not ask any question again for this forum !!



thanks all

 

[Lancie1]

the figure c explains the delta connection which are two phases between two hot wires B , C ..

NO! NO! NO! Between wires B and C there is only one "phase". Between (or across) ANY two hot wires of a transformer there is ONLY ONE phase (whether the transformer is delta-delta or delta-wye or some other configuration).

The above error in your thinking is leading you to a lot of confusion and mistakes.

 

[magdyfayad]

thanks all


as i told before that is enough for this forum for me and i do not ask any question again for this forum !!

and i thank keithkyll , Lancie1 , Jim Dungar , tomalbright , and leitmotif


i took some very important basics from this discussion

thanks all

 

[Lancie1]

...but first three is a plural so we must say three apples and also must say three phases , what is the difference ??

To use techincally correct English, the term is "3-phase". Thus you can say "3-phase power, 3-phase voltage, or 3-phase current". 3-phase used like this is an adjective modifier, describing "what kind".

On the other hand, in "3 phases", the phases is a noun, and the 3 is an adjective teling how many. To say "3 phases power" is using incorrect English grammar. You would be putting two nouns together back-to-back, which is usually a grammar mistake.

For example: "That is an apple orange" would be confusing and not mean very much to most people. Two nouns, apple and orange, next to each other do not reveal the real meaning.

If I said instead: "That orange looks like an apple", it would be clearer. "That is an apple-looking orange" would be equivalent in grammar structure to "That is a 3-phase power line".

You can say: "That power line has 3 phases".
You can say: "That is a 3-phase power line".
You should not say: "That is a 3 phases power line".

The lowly and often forgotten hyphen makes all the difference.

 

[magdyfayad]

thanks again Lancie1

good information to me

 

[keithkyll]

I was patient with you. Now I ask you to do one thing. Study one subject - Generators. Instead, you say 'enough' and you are leaving? Does this mean you are too lazy to study what I ask?

 

[magdyfayad]

i know you are patient with me , so i thank you more times

but , i am not lazy !!

i want to study and study !! as i asked power electerical engineers at Egypt and also i asked you and put my questions here to collect the basics for this forum , but the problem i have not any good idea about generators or the electerical power , as the basics for the electerical power in general are not clear to me !!

as you know the main reason for this forum which i do not understand why the seconfary of the transformer - which is applied to a bridge four diodes - are two hot conductors with a nuetral as at USA homes and we called these two hot conductors are in phase not two phases !!

at all i thank you again for your help

and i repeat there is no doubt i benefit from you at this discussion and all your disccusions with me
thanks all

 

[Lancie1]

As you know the main reason...which i do not understand: Why the seconDary of the transformer - which is applied to a bridge four diodes - are two hot conductors with a nuetral (as at USA homes) and we say these two hot conductors are "in phase", and not two phases !!

Two conductors do not make two phases. To create one phase, it takes two conductors. To create 3 phases, it takes 3 conductors. Each phase of a 3-phase system shares each conductor with another phase.

A "phase" is a concept that only exists and can be measured and observed BETWEEN two conductors, not at the nodes, poles, or points where the conductors are connected.

 

[magdyfayad]

thanks again Lancie1

thanks all