ggunn
PE (Electrical), NABCEP certified
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- Austin, TX, USA
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- Consulting Electrical Engineer - Photovoltaic Systems
Crossthreading alert!
2 Phases of a 3 Phase System
- Thread starter Fitzdrew516
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ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
Relative to what? Take a piece of paper, rotate it to a random orientation, and draw a single line on it. What is the angle of that line?
No. :happyno:
Over on Dictionary.com is a blog about just this issue.
http://blog.dictionary.com/fewer-vs-less/
Comment on that blog:
mivey
Senior Member
Did they have a listing for "burn"?
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
Phase angles are relative. If all you have is a single wire for a three phase system I maintain that it makes no sense to call out a phase angle for that conductor. It is 120 degrees ahead of one of the other conductors and 120 degrees behind the other, but without something to reference it to, a phase angle makes no sense. If you draw a vector out in space with no coordinate system to reference it to, it has no angle.
winnie
Senior Member
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- Springfield, MA, USA
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- Electric motor research
An AC voltage can be represented by cos(omega*t + p) or Re(e^(j * omega* t +p) or by whatever 'sine' type function suits your fancy. That sine function has a phase.
So if you have _any_ AC voltage you can say it has a phase.
But it is still relative to something, because you have to have a time = 0 reference somewhere.
Phase angle _difference_ is the only useful measure of phase. This might be phase angle difference between different lead pairs in a power distribution system, or phase angle difference between two systems about to be connected, or even phase angle difference caused by modulation.
Yes, your single phase system will have a phase angle relative to the USNO clocks, but that doesn't help you run a motor.
-Jon
So if you have _any_ AC voltage you can say it has a phase.
But it is still relative to something, because you have to have a time = 0 reference somewhere.
Phase angle _difference_ is the only useful measure of phase. This might be phase angle difference between different lead pairs in a power distribution system, or phase angle difference between two systems about to be connected, or even phase angle difference caused by modulation.
Yes, your single phase system will have a phase angle relative to the USNO clocks, but that doesn't help you run a motor.
-Jon
:?Did they have a listing for "burn"?
Not from where I sit.
mivey
Senior Member
As in: Duuude! Burrrrn!
Probably not in that sense of the word... but that's just a guess. :happyyes:
Then might I politely suggest that you read the quote I posted which is from the definition you kindly cited?
But we ought to return to the topic.
With just the voltage between two lines there is no voltage phase shift to measure. Thus it is single phase. Whether there a phase shift between current voltage because of a non-zero power factor doesn't alter that. It's an irrelevance.
You forget... that quoted comment was written by a person representing Dictionary.com. That person is no more credible than you or I when it comes to the adoption of English grammar rules.
Additionally, this is just another cascading of "As with many prescriptivist grammar rules, someone transcribed that opinion into a book and suddenly it became standard." I'm not saying you are wrong for subscribing. I'm just cascading "Quite simply, using 'fewer' or 'less' for countable things is strictly a personal choice."
I agree.
But it concurs with the J. C. Nesfield manual of English grammar and composition that sits on the shelf above my desk. Along with the Chambers Dictionary.
I'd take these as more credible sources than you or I.
Personal choice does not ascribe validity or accuracy.
Good. At least we agree on that matter which pertinent to the topic.
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FIFY
Although the argument can be made that it is part of an elliptical prepositional phrase rather than the object of the preposition.
(...than you are or I am.)
Examples: "My brother is 6'3'' and therefore is taller than me" versus "My brother is 6'3'' and therefore is taller than I am."
Credible only in cascading the original opinion, not in the validity or accuracy of that opinion.
Is zero less than one? ...one less than two? We all know each to be true. So to ascribe to the 'rule' is to say the conclusion just stated is invalid.
- Location
- Placerville, CA, USA
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- Retired PV System Designer
That is a shaky example, since you are dealing with mathematical cardinal numbers for which a greater than/less than formal ordering exists.
That one is less than two is not enough to say that one apple is less than two apples. (Although in quantity of apple it usually is, apples being equal.)
If I were making applesauce, the recipe might call for more than three and less than five apples but I might have fewer than five apples in my basket.
I try to avoid pontificating about prescriptive grammar whenever possible. But I will use descriptive information to indicate what is currently considered to be "proper" English.
jumper
Senior Member
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When did I join an English grammar forum?:huh:
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