K2500 said:
We've been working long hours, sorry for the delay.
No apology necessary, but appreciated all the same.
Take it easy guys, I think if you take a look back through the thread, that you will find that you are both right from one perspective or another.
Thank you.
That said, this is where I am at:
I have no formal higher education. I metioned previosly that I was begining to study PF, then decided, after reviewing this thread(once again) that an understanding of vector math would be nessasary to do this. The majority of my studying lately has been here
http://www.ibiblio.org/obp/electricCircuits/AC/AC_2.html
Are you not participating in a formal apprenticeship program? Recognized apprenticeship programs are a form of formal higher education. I heard some even provide participants with college credits.
The website you linked has some great reference material.
I study on my own time, when the days work is done, so I apologize for the amount of time it takes for me to reply(where is spell check
). I'm still looking for a decent app to apply the vector stuff, once i find it, I will be able to toy with more (hypothetical type) problems. I can only learn so much just reading about it.
The initiative you demonstrate is commendable.
To achieve Rms values I'm thinking I would take the product of the waveform peak and .707. Would I be able to take the avarage multiplyed by 1.414 to get the peak, then go from there? Is the practical avarage, as apposed to the technical avarage of 0, the same as nonimal(120, 240...), are these even the correct multiplyers for this application?
I'm not sure what you mean by practical average, but the relationships are:
Effective value = 0.707 ? maximum value
Maximum value = 1.414 ? effective value
Average value = 0.636 ? maximum value
Maximum value = 1.572 ? average value
The average value is not much use to practical people... [I see in the midst of previewing my message that rattus has covered this and elaborated already. There is no point in my being redundant :wink: ]
How do the reistive loads cause the current to lag the voltage?
You have gotten the wrong impression somewhere along the line. Purely resistive load current neither lead nor lag the voltage. However, there may be some reactance (induction) on the circuit from wiring method. That causes lagging current, but it is usually minimal in effect.
It seems like peak power occours at the intersection of the V and I waveforms, so I can see why a (unity?)PF would be the most efficient. Why do reactive loads cause a leading PF?
Reactive loads are ones which have at least two [edit: which are resistive and one other type, though the resistive component may be very near zero], but possibly all three types of impedence: resistive, capacitive, and inductive (RCL for short). Capacitive reactance results in a leading current and inductive a lagging current.
Would a three phase induction wound motor be considered a purely reactive load?
No. While it achieves its purpose through induction, it also has at least a resistive component to its impedance from the wire used in its windings.
On a system that is technically a three phase four wire wye, but in practice is a three phase three wire, would load balance be of much greater importance or less? The system in question is 480v with the neutral feeding only the HRG equipment.
"...feeding HRG equipment"? High resistance grounding equipment? Help me out here, I must be having a premature senior moment
Balancing a system is more critical when the system is heavily loaded. Whether the system is being utilized as 3?, 3-wire or 4-wire makes no difference AFAIK.
Belive me when I say, I have more questions than the ability to conjure them. Thank you for all the replies.
I thought as much... but keep 'em coming :grin: