chris kennedy
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All in good fun my friend. Now back to the topic at hand.
What was the topic???
Power factor and VA vs Watts
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All in good fun my friend. Now back to the topic at hand.
What was the topic???
Hameedulla-Ekhlas
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The topic is Real, Reactive, apparent and power factor. I think , long long discussion has been done.
The point here is that we have instantaneous information for a time period equal to or exceeding one cycle of voltage (or current, or two 'cycles' of power). So the correct statement would be instantaneous current times instantaneous voltage is instantaneous apparent power at every instance, for we know from the collective information there is an out-of-phase relationship between current and voltage.
Hameedulla-Ekhlas
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Smart$:
Let me add some informtion. Since rattus explained v(t) / i(t) equals to a constant number same for reactive. So, Constant number is a real number same as Resistive and dut to voltage divided by current as a general it is called watt for an instantaneous power for an instant of time.
We are not discussing v(t)/i(t) here. We are discussing v(t)?i(t) where t has a range of at least one cycle. No one is contending that the v?i product is not expressed in units of a watt.
However, from the power engineering aspect of the discussion, we dub the v?i product as volt-amperes (VA), which is an electrical equivalent unit of measure to watts. We do this to distinguish apparent (VA), real (Watts), and reactive (VAr) power. Each of these units of measure are equivalents. This is no different than 1 red delicious apple + 3 yellow delicious apples = 4 differently-colored apples. But they are all apples. I don't know how many times this has to be reiterated before it sinks in... but I'll do it however many times is necessary.
Hameedulla-Ekhlas
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sorry for mistake, I meant just consider it v(t)*i(t) for power but it is still not look good for me to call it VA. I know it does not make any difference here saying watt or VA but I feel like this to say watt.
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Not a problem by me, as long as you don't try to correct me for using VA.
mivey
Senior Member
Is that even possible? :grin:
Can you throw a potato chip? Can you bend a cracker? If so, then maybe so!
Sure... trying is possible
I can do both
Hameedulla-Ekhlas
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Not a problem by me, as long as you don't try to correct me for using VA.
Ok now lets bring some changes.
Just say yes, or no
1- v(t) / i(t) = Constant (K) or real number or R with unit ohm
2- p(t) = v(t) * i(t)
Now v(t)*i(t) what will you call this
1- Real power or watt
2- Apparent power VA
3- product of Voltage and current VA
But I will think the difference between these two like this
"Apparent power ( VA ) is the product of RMS voltage and RMS current. True (or active) power is a time average of the instantaneous power (product of instantaneous voltage and current."
I need others comment too for deffination
weressl
Esteemed Member
Time period and instantaneous is contradiction in terms. Instantaneous current and isntantaneous voltage is instantaneous real power at every instance.Out of phase only exist in TIME.
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Not precisely...
A more precise statement is time period and an instant are a contradiction in terms.
Let's say we have two sets of values representing exclusive instances of a mutual event: v1 and i1, and v2 and i2. The 1's correlate with each other as being values of one instant in time, as does the 2's being of another instance in time. However, all four are instantaneous values with time being involved, as they cannot be of the same instant in time.
There is no [ultimate] rule or law that says we cannot evaluate multiple instants in time, and the proper descriptive term (adjective) for the instantaneous values at different times is still "instantaneous".
There is no point to discussing this aspect until you accept the premise I described above.
weressl
Esteemed Member
There is not point in discussing anything on a false premise.
I couldn't agree more, but yet you seem to be hypocritical in this regard
Nope.
Just power.
weressl
Esteemed Member
Unless, unless, unless, unless, unless, unless, unless, unless, unless, unless, unless, unless, unless, .........V1 and I2 is involved AND the T1-T2 equals the phase shift between V and I.
Of course those are NOT an instantaneous measurements in the SAME instant. Humpty-Dumpty weould be preoud!
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Back at it again
Well I guess I'll have to approach from a different perspective. Hopefully not a futile attempt...
As we know, all the variables we use in rms/average calculations have their instantaneous counterparts. For apparent, real, and reactive power, please show me their instantaneous counterparts in some form.
On what throne does or did the person that said we had to use instantaneous measures of the same instant sit? Perhaps he sits in your bathroom?Unless, unless, unless, unless, unless, unless, unless, unless, unless, unless, unless, unless, unless, .........V1 and I2 is involved AND the T1-T2 equals the phase shift between V and I.
Of course those are NOT an instantaneous measurements in the SAME instant. Humpty-Dumpty weould be preoud!
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