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- Licensed Electrician
Lots I don't know either. I did not know that that the cap in HID a fixture was for power factor correction. Did you?
150 watt hps
- Thread starter domnic
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jumper
Senior Member
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Nope. I just wired it up, never thought why.
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- Massachusetts
I am not sure all HID caps are for PF correction.
I don't recall seeing a capacitor in an HID fixture that was connected line to line ahead of the ballast.
They always seem to be in series between the ballast and the lamp.
Or on its own winding.
I don't recall seeing a capacitor in an HID fixture that was connected line to line ahead of the ballast.
They always seem to be in series between the ballast and the lamp.
Or on its own winding.
- Location
- Massachusetts
I am going with 'It depends on the application' if the cap is for PF correction or some other function.
Here is a cut sheet that seems to show the OPs application. An optional line to line connected cap. I don't think I have ever seen that out in the wild.
http://www.venturelighting.com/VLPS/BallastDataSheets/HPS/V90B1422.pdf
Here is a cut sheet that seems to show the OPs application. An optional line to line connected cap. I don't think I have ever seen that out in the wild.
http://www.venturelighting.com/VLPS/BallastDataSheets/HPS/V90B1422.pdf
kwired
Electron manager
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- NE Nebraska
I don't believe the primary function of the capacitor when in series with the lamp is PF correction either, but I also think it still does improve PF to some degree. Seems like all luminaires with a capacitor in them have fairly high power factor.I am not sure all HID caps are for PF correction.
I don't recall seeing a capacitor in an HID fixture that was connected line to line ahead of the ballast.
They always seem to be in series between the ballast and the lamp.
Or on its own winding.
Same for a PSC motor where the capacitor is in series with a winding, they usually have higher PF then a similar size motor that doesn't have a capacitor. The primary function in such a motor is phase shift to develop torque - not sure what the function of the capacitor in series with the HID lamp is though.
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Approximately.
mbrooke
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I am not sure all HID caps are for PF correction.
I don't recall seeing a capacitor in an HID fixture that was connected line to line ahead of the ballast.
They always seem to be in series between the ballast and the lamp.
Or on its own winding.
Jeez, am I talking to actual electricians? :blink::slaphead:
That's because your showing a CWA ballast followed by a magnetic regulator. CWA, CWI and Regulated lag (3 core ballasts) all use the capacitor as a method of regulating lamp wattage and limiting arc current in addition to power factor correction (one reason the slightly off term constant wattage applies to them). Plus the advantage of lower starting current vs running current. R-HPF and HX-HPF ballasts on the other hand only use them for PF correction and can functionally operate without them. Yes, caps are connected line to line, or line to auto transformer tap for multi-tap ballasts so each voltage doesn't need a different cap.
The ballasts in question are pure inductors or inductor auto transformer types (reactor and reactor auto-transformer) which do not use a capacitor for lamp regulation. If they did and ran without a cap they would have failed thus far.
Reactor and HX-NPF all have the option of a cap connected before the ballast line-line. These ballasts make up 90% of low wattage 150 and below high power factor lighting fixtures. Just because you have never seen a high power factor reactor or HX ballast doesn't mean they doesn't exist.
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- Massachusetts
Jeez, am I talking to someone who can follow a thread? :blink::slaphead:
I will try to 'splain it to ya.
I jumped in when I read this exchange.
It seemed to me that Dave and jumper had jumped to the conclusion that caps in HIDs were only for power factor correction. I felt that might be incorrect.
I offered up some examples in my first post of what I had worked with and did not believe the caps in those examples where for PF correction.
After that post I kept looking for more info and finding the document I posted showing what you were talking about. While I have worked with many of those ballasts the caps were absent.
Never said that, I even posted a cut sheet with diagram showing one.
My point was simply that I have not been finding line to line connected capacitors in those ballasts in the real world. That being the case I doubt Dave or Jumper have been working with them either.
Capeesh?
mbrooke
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Ok good enough
:lol: I thought you were referring only to my comment... sorry for the misunderstanding! :ashamed1:
jumper
Senior Member
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Ain't seen, worked, or ever heard (til now) of one.
Cap has always been inline between ballast and lamp like diagram#1 you posted.
- Occupation
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Yup. Same for me too. Had no idea till iwire posted that pdf.
kwired
Electron manager
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- NE Nebraska
I can't recall ever seeing a ballast not inline with lamp either, didn't really know what it's purpose was being in line, but did figure it still had some impact on power factor as well.
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