please refresh my memory: what a PFC capacitor does and a real life example of what it mea...

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I recently installed a mercury vapor light fixture.  It is a 125 W lamp  
with integrated ballast in the housing.  Today, I check the current with  
a clamp ammeter on the 120 VAC/ 60 Hz line going into the housing.  
After a 10 minute warm up, the current reads approximately 2.3 A AC.  
Not being sure, I then wired a series multimeter in line for a moment  
and it too read 2.3 A.  Unfortunately, there is no PFC with this yard  
light, only the bulb and ballast, so I don't think anything can be done.  
  However....

In another set up I have on the way, there is the 175 W MV bulb, ballast  
and the PFC capacitor that will be used with the ballast.  Any ideas as  
to performance would be welcome.  I'm just looking for in general as I  
realize we can't get too specific without any more figures, but I'm  
really hoping the efficiency is better than with the 125 W set up.

Thank you in advance.

Re: please refresh my memory: what a PFC capacitor does and a real life example of what it means??
wrote:

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Since I have no idea about them I searched for > PFC capacitor <
and there is plenty of information about them which my help you.


KenW

Re: please refresh my memory: what a PFC capacitor does and a real life example of what it means??
On 9/22/19 2:42 PM, KenW wrote:
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I was just hoping to cut to the chase with someone using the examples  
above.  I'm not all that pleased with the lack of efficiency with the  
125 W lamp, just wondering if the capacitor would increase efficiency  
with the 175 W set up.

At one time, 25+ years ago, in college, we actually had to calculate the  
correct capacitor to use in a circuit for PFC, but that's the last time  
I did it.

Re: please refresh my memory: what a PFC capacitor does and a real life example of what it means??
On 9/22/19 2:42 PM, KenW wrote:
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Ok, this shows me what happens:


https://www.youtube.com/watch?v=dPFKcUxbNuQ


Great refresher!  So the capacitor in the mercury vapor circuit should  
reduce the current if matched correctly.  I wonder why there is no such  
capacitor in my 125 W mercury vapor yard light?

Re: please refresh my memory: what a PFC capacitor does and a real life example of what it means??
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Because it does not really matter for lamps that are typically used
solitarily or with 2 or 3.  It is of course different when hundreds
of streetlights have to be powered.

Re: please refresh my memory: what a PFC capacitor does and a real life example of what it means??
On Sun, 22 Sep 2019 15:02:07 -0400, Larz wrote:

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Obviously not *that* great.


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Oh dear oh dear.



--  
This message may be freely reproduced without limit or charge only via  
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Re: please refresh my memory: what a PFC capacitor does and a real life example of what it means??
Larz is amongst the Invincibly Ignorant - reminds me of Jimmy Neutron it its own way - might even be the same creature.  

Let it be.

Peter Wieck
Melrose Park, PA  

Re: please refresh my memory: what a PFC capacitor does and a real life example of what it means??
On 23/09/2019 14:43, snipped-for-privacy@aol.com wrote:
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Wait till it starts posting lots of links and answers its own questions.

Then you have id :-)

--  
Adrian C

Re: please refresh my memory: what a PFC capacitor does and a real life example of what it means??
On 9/23/19 10:25 AM, Adrian Caspersz wrote:
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*Laughs* You're thinking of that carbuncle on the ass of humanity Arlen
Holder.


--  
"I am a river to my people."
Jeff-1.0
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Re: please refresh my memory: what a PFC capacitor does and a real life example of what it means??
You know, everytime I post here I am met with sarcasm and other negative  
commentary.  I asked a simple question and only two people answered,  
appropriately.

You might be surprised what degrees (yes, degrees) I have, but none in  
electrical engineering.  I did have an electric circuits course as part  
of my major, but that was over 30 years ago and I forgot some things.  I  
never have liked working with AC and maybe, if you do in fact want to  
poke fun at my questions as some obviously can't seem to resist for some  
odd reason, then credit my lack of AC knowledge as the reason.  I much  
prefer DC, but unfortunately these lamps need AC circuitry.

So.... that being said.... I won't bother this patronizing, sarcastic  
group anymore.  I must say I have been using Usenet in various  
capacities for over 20 years and I have never been meet with conduct  
like I'm experiencing here.  Some of you must be college professors  
because you are a lot like some of the aholes I had.

I bid you farewell.  My hat is off to you.  Whatever floats your boat,  
but know this: I won't respond nor post any further commentary in this  
pathetic group.  Goodbye.

Re: please refresh my memory: what a PFC capacitor does and a real life example of what it means??
On 9/23/19 1:55 PM, Larz wrote:
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d,  
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I take some of this back:  I will, in the future, respond to those who  
responded to me appropriately but as for the rest, you are being  
filtered.  I won't let the negativity and sarcasm of a few select ruin  
it for those who did answer or try to answer appropriately.


Re: please refresh my memory: what a PFC capacitor does and a real life example of what it means??
On 9/22/2019 2:02 PM, Larz wrote:
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  Kind of interesting, this website shows an electric motor has a PF of  
0.15 with no-load, and 0.7 to 0.85 with a load.
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                                         Mikek



Re: please refresh my memory: what a PFC capacitor does and a real life example of what it means??
amdx dickhead wrote:

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 https://www.electricalengineeringtoolbox.com/2016/12/typical-power-factors-for-common.html

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** Fraid the info is so minimal, it's highly misleading.  

Motors used in domestic appliances like washers and fridges operate on full or near full load at all times - so have good PFs.

What they might do off load is not important, as it is very rare.  

In any case, the current draw and power consumed off load is much lower.  



....   Phil  

Re: please refresh my memory: what a PFC capacitor does and a real life example of what it means??
On 9/23/2019 10:11 PM, Phil Allison wrote:
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  The reference was to the video where he used an unloaded motor.
Then as you say, "current draw and power consumed off load is much  
lower". So how often do you run a motor unloaded and is it worth the  
cost of PFC.
  How often does a factory run a motor unloaded?
                                    Mikek

Re: please refresh my memory: what a PFC capacitor does and a real life example of what it means??
Larz wrote:
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** You are working under a serious delusion.  

PFC caps or circuits have *NO* effect on a device's efficiency.  

Power consumption remains exactly the same, with or without.  

The sole purpose is to reduce the *current draw* and allow more lights or whatever to be used on the same AC supply circuit.  

Current draw that is non-sine wave or not in phase with the voltage is always higher than when it is.  


.....  Phil  



Re: please refresh my memory: what a PFC capacitor does and a real life example of what it means??
On 9/22/19 11:05 PM, Phil Allison wrote:
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Ok, I can accept that answer and will try and learn more.

Re: please refresh my memory: what a PFC capacitor does and a real life example of what it means??
On Sunday, 22 September 2019 19:30:46 UTC+1, Larz  wrote:

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done about what?

PFC is normally immaterial in domestic discharge lamps. You're not paying for the reactive current.


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google mercury lamps to get the figures. They're poor compared to fluorescent, led, sodium or more modern discharge lamps, hence they're obsolete.


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higher power discharge lamps do tend to be more efficient, but you're stuck with a poor efficiency lamp. Unless you change the lamp for something compatible & a lot more modern.


NT

Re: please refresh my memory: what a PFC capacitor does and a real life example of what it means??
On 9/23/19 5:27 AM, snipped-for-privacy@gmail.com wrote:
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Thank you!

Re: please refresh my memory: what a PFC capacitor does and a real
On Sun, 22 Sep 2019 14:30:42 -0400, Larz wrote:

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Without a Wattmeter, you have no idea what the actual power draw is.  
Some of that 2.3 A is reactive current, at 90 degrees to the voltage, and  
you are not billed for that.  Measuring the current and voltage  
separately, you only get the VA (volts * amps) which is NOT the power in  
Watts.

Jon

Re: please refresh my memory: what a PFC capacitor does and a real life example of what it means??
systems.com says...
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I never could get it in my head about AC power either.  I know how volts  
or amps can lead if there is any reactance in the circuit.  I have an  
inline power meter that shows voltage, current, and power (watts )_ A  
heater element will show about the same watts as the voltage times the  
courrent.  A load with a large transformer in it will show a much  
differant V times A than the watt meter.  I understand it doing that,  
but not how the power company realy charges for the power.


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