Need to clarify this

Discussion in 'Homework Help' started by bwd111, Aug 7, 2013.

  1. bwd111

    Thread Starter Member

    Jul 24, 2013
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    In one of my post I was told that E stands for line voltage and E should be phase voltage in this equation if Im thinking this out correct in the calculation P=√3 x E X I

    (√) I know this isn't the correct symbol and I don't know how to get the squared symbol to show
     
  2. WBahn

    Moderator

    Mar 31, 2012
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    The use of E and V is not very standardized. Both generally mean electromotive force, which is measured in volts.

    Similarly, what is meant by the term "line voltage"? Is it the voltage between one line and another? Or between one line and ground (or the neutral)? In most cases, it means line-to-line, but there, in practice if nothing else, there isn't universal agreement on what "line voltage" means and what "phase voltage" means. So best to be explicit in any situation in which it matters.

    To get the "squared" symbol, use Alt-253 or just type ^2. So 3^2=3²=9.

    If the square root symbol isn't the one you wanted and you wanted the squared symbol instead, then what equation were you trying to express? It sounds like it was completely different than the one you actually expressed, which begs the question of what purpose was served by posting an equation that you believe is incorrect?
     
    studiot likes this.
  3. studiot

    AAC Fanatic!

    Nov 9, 2007
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    Alt + 253 - I never knew that.

    Thanks.
     
  4. WBahn

    Moderator

    Mar 31, 2012
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    Someone (Georacer?) has a blog or a sticky somewhere that lists many of the Alt-code characters. I used to use them alot (I didn't even know about the panel of characters that has many of them in the Go Advanced mode).

    Unfortunately, most of my work is now done from a notebook without using an external keypad and I've never figured out how to input Alt-codes with it. So I've forgotten most of them. But you can quickly run through many of them by holding down alt, entering the code, and briefing releasing the alt key. The nice thing about entering the characters via alt-codes is that the cursor automatically advanced, unlike when you select them from the Go Advanced side panel.
     
  5. bwd111

    Thread Starter Member

    Jul 24, 2013
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    So are you that E is line voltage or voltage to ground or voltage to netural in that calculation? and not phase voltage when its a calculation for three phase? If I learned anything from all my post it was that one simple calculation
     
  6. WBahn

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    Mar 31, 2012
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    Go back and look at where I have used that equation and you will see that I have explicitly stated what the necessary conditions were.

    This is why it would be a good thing for you to work through the derivation of that equation yourself. So that you don't have to rely on memorizing what someone else somewhere on the internet has told you.

    Just make a start at an attempt and I will help you work through it.
     
  7. bwd111

    Thread Starter Member

    Jul 24, 2013
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    I know it is phase voltage and going on that
     
  8. WBahn

    Moderator

    Mar 31, 2012
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    You do? You know this how? It came to you in a vision? A dream?

    What do you mean by phase voltage? The voltage from one each phase to ground?
     
  9. bwd111

    Thread Starter Member

    Jul 24, 2013
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    Missed the test question where the correct answer was line to ground
     
  10. t_n_k

    AAC Fanatic!

    Mar 6, 2009
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    @WBahn

    How does the proverb go ..

    "You can lead a horse to water .."
     
  11. WBahn

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    Mar 31, 2012
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    My version: You can lead a student to water, but it's still a felony to drown them.
     
    Last edited: Aug 8, 2013
  12. LDC3

    Active Member

    Apr 27, 2013
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    That's not a felony, unless you're missing an 'r'.
     
  13. WBahn

    Moderator

    Mar 31, 2012
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    What missing 'r'? :rolleyes: ;)
     
  14. WBahn

    Moderator

    Mar 31, 2012
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    All the more reason to walk through it yourself.

    Why are you so adamant about not wanting to understand anything about the field you are studying? Do you want to be nothing more than an equation monkey that is a disaster waiting to happen?
     
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