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

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.

Reply to
Larz
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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

Reply to
KenW

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.

Reply to
Larz

Ok, this shows me what happens:

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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?

Reply to
Larz

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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

Reply to
Phil Allison

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.

Reply to
Rob

done about what?

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

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

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

Reply to
tabbypurr

Obviously not *that* great.

Oh dear oh dear.

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Reply to
Cursitor Doom

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

Reply to
peterwieck33

Wait till it starts posting lots of links and answers its own questions.

Then you have id :-)

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Adrian C
Reply to
Adrian Caspersz

*Laughs* You're thinking of that carbuncle on the ass of humanity Arlen Holder.
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Reply to
Fox's Mercantile

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.

Reply to
Larz

Ok, I can accept that answer and will try and learn more.

Reply to
Larz

Thank you!

Reply to
Larz

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our boat,

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.

Reply to
Larz

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

Reply to
Jon Elson

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.

Reply to
Ralph Mowery

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.

Mikek

Reply to
amdx

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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

Reply to
Phil Allison

Wow, I didn't know this or had forgotten. I am fully used to working with DC, seldom AC I see digital plug in wattmeters on Amazon in the $10-15. Would something like those be satisfactory? I really would like to find out the true wattage.

Reply to
Larz

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