Current and voltage Waveforms

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K8MHZ

K8MHZ

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electrics said:
http://books.google.com/books?id=h1...&resnum=1&ved=0CCUQ6AEwAA#v=onepage&q&f=false

Here in 214. page the current and voltage waveforms are given as sum of two different sinus waves, why?

İn fact any sinusoidal current or voltage is sum of all its harmonics and fundamental wave, so why is there indices such as m,n,p instead of only n?
İs not it bizarre? why does this book takes a current as sum of two different (frequency ) sinus waves?
Click to expand...

I went there and there is no page 214. Between 213 and 215 is the number 214 followed by some foreign words.
 
glene77is

glene77is

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Electrics,

It refers to figure 7.28, an example of a Non-Linear Load and a Capacitor.
This would be the complex waveform for the equation.

This looks like a good read, thanks for the link. :)
 
Smart $

Smart $

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electrics said:
http://img828.imageshack.us/img828/2859/adsznd.jpg

Not at all, but I cant understand what do the orders m,n,p here mean? it is weird for me.
Click to expand...

(n) signifies variables of the initial phase and phase-shifted waveforms.

(m) and (p) signify variables of an initial waveform harmonic, respective of voltage and current.

The equations only encompass the initial and one harmonic waveform. There are better ways to write the equations and include all harmonics.


Usage of parentheses around subscripts, a very unusual convention in my opinion, is enough to scare me away from the book as a reference :D
 
J

jghrist

Senior Member
Smart $ said:
(n) signifies variables of the initial phase and phase-shifted waveforms.

(m) and (p) signify variables of an initial waveform harmonic, respective of voltage and current.

The equations only encompass the initial and one harmonic waveform. There are better ways to write the equations and include all harmonics.
Click to expand...

I thought so too at first, but there are summations for m, n, and p, indicating that each is a range of values.

I don't know why there are more than one range of harmonic orders.
 
E

electrics

Senior Member
no I dont agree, there are two different sinus wave summation with different orders , not one sine wave (fundamental )plus harmonics, it is many sine waves plus many sine waves, it is ununderstandable for me...
 
Smart $

Smart $

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jghrist said:
I thought so too at first, but there are summations for m, n, and p, indicating that each is a range of values.

...
Click to expand...
Look again at the summation symbol. There is no upper range value or variable (should be just above the top of the symbol)... just a single variable at the bottom.

I understand this can be interpreted to mean a set or range of values for m, n, and p, respectively... but I don't see that set or range defined anywhere.
 
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wirenut1980

wirenut1980

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Plainfield, IN
The formulas are under the sub-heading "power factor", so I wonder if the first term in each formula should be cosine and not sine? To signify real and reactive parts of the current...but that explanation does not explain why it is that way in the voltage equation...I give up!:confused:


The formula does not make sense to me either as written. Too many summations.
 
J

jghrist

Senior Member
But the power factor is taken care of by a constant angle ? in the first of the current terms. Why only in the first term? Another mystery that might be cleared up if we knew what the second term was there for.
 
mivey

mivey

Senior Member
electrics said:
Here in 214. page the current and voltage waveforms are given as sum of two different sinus waves, why?

İn fact any sinusoidal current or voltage is sum of all its harmonics and fundamental wave, so why is there indices such as m,n,p instead of only n?
İs not it bizarre? why does this book takes a current as sum of two different (frequency ) sinus waves?
Click to expand...
The author is distinguishing between the load voltage & current (n terms) and any series voltages (m terms) and parallel currents (p terms) between the load and the source.
 
mivey

mivey

Senior Member
Smart $ said:
Usage of parentheses around subscripts, a very unusual convention in my opinion, is enough to scare me away from the book as a reference :D
Click to expand...

electrics said:
There is no still a good answer, I think this is a difficult question, or maybe the book is wrong..
Click to expand...

Nah, The author is Italian so his notation (and some of the terms he uses) might be a little different than what we are used to. I have the book and it is a good reference.
 
mivey

mivey

Senior Member
jghrist said:
But the power factor is taken care of by a constant angle ? in the first of the current terms. Why only in the first term? Another mystery that might be cleared up if we knew what the second term was there for.
Click to expand...
Because the "n" terms are for the load and ? shows the phase shift between voltages and currents in the load. The other terms are for other loads, etc. between the nonlinear load of interest and the u(t) source. The others result in series voltages and parallel currents that also impact the source that feeds the nonlinear load we are investigating.
 
Smart $

Smart $

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Location
Ohio
mivey said:
Nah, The author is Italian so his notation (and some of the terms he uses) might be a little different than what we are used to. I have the book and it is a good reference.
Click to expand...
Tends to make me question math as being the universal language :D
 
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