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High Pressure Mercury Lamps

Sigurthr

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Anytime, =) .

Interesting forum there!

Yeah, the incandescence of the electrodes and the electron/ion interactions all create continuum bands, which are often swamped out of our vision by the strong emission bands. Feel free to post the image I linked on that other site for the benefit of all, I don't mind, and I'm not about to register to do it.

Re: 405nm; an interesting coincidence is that nearly all of the common laser wavelengths lie close to emission spectra of Mercury. It's one reason I'll always lust over a HeHg or Hg-ion laser.

Starlight: your shutter speed is running at a harmonic of the ballast frequency, adjust your shutter speed to compensate.
 



The Lightning Stalker

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How the heck do I photography HPS lights? I get the scrolling lines in the camera screen and lines in the pictures when taken. My MH light is doesn't happen.
Aperture mode, set ISO as low as it will go,
stop all the way down, shoot through a ND
filter if you have to. (Or several, welding
mask, etc.)

Oh, and it should be very obvious, but do
not use flash!

- Oh, wait, you are using a RAZR
cameraphone, I'm not sure what settings
those have for the camera, but otherwise I
don't think there is much you can do
besides shooting through a neutral density
filter.
 
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DashApple

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tiny gap in the phosphor coating on my 1.25kw SB Mercury lamp , Made for a good internal photo -

230V AC , 1.25Kw Arc tube and tungsten filament ,

IMG_1024 by TwirlyWhirly555, on Flickr

IMG_1025 by TwirlyWhirly555, on Flickr

Photos are as best as I could get , the gap was only about 4mm wide .
 
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trencheel303

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Saw that on LG - are you sure it's a 1.25kW Arc tube? Normally in SB mercs the stated wattage includes that of the arc tube and the filament, so the arc tube in these would be like 500W or something. Although I know you had them custom made so it may be a different story?
 

DashApple

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Saw that on LG - are you sure it's a 1.25kW Arc tube? Normally in SB mercs the stated wattage includes that of the arc tube and the filament, so the arc tube in these would be like 500W or something. Although I know you had them custom made so it may be a different story?
If that's how they are spec'd then its 1.25Kw overall as you said , Arc tube and filament together .

I just kinda worded it very wrong : P .


I did get them made to order from the EYE catalogue , after I spoke to a sales person this was the largest and only SB of this size they made as I was originally after another 1Kw SB lamp .
 
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trencheel303

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Yeah definitely - those filaments look like they've got balls of steel too :p

what's the rated life - do EYE even give one? I have an SB merc but it's tiny compared to these, 160W total and it's rated at a generous 6000 hours.
 

DashApple

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Yeah definitely - those filaments look like they've got balls of steel too :p

what's the rated life - do EYE even give one? I have an SB merc but it's tiny compared to these, 160W total and it's rated at a generous 6000 hours.
Haha Yeah :p

EYE specs for the 1.25Kw Flood SB is -

Rated life -16000 Hours
Beam Lumenst - 26000 ( I think that's total lumens but im not sure )
Running current 6.1A .


The Clear non flood 1.25Kw SB is rated to 39000 lumens

Data sheet - http://www.eye.co.jp/sources/mercury/pdf/p52-53.pdf , Mines the 1250WSB/R88 Flood
 
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trencheel303

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16,000 hours is an epic lifetime for a tungsten filament, I wonder if they use one rated for 415 volts or something (if there is even a thing) to result in hugely prolonged life? TBH that's a pretty ideal lifetime as by then the arc tube will be starting to lose lumens at a steep rate and you're beginning to creep into failure territory past early failures as well.
 

The Lightning Stalker

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I'm guessing the filament runs colder than
its incandescent counterparts. They can
get away with that since they have the MV
tube to generate most of the light. The
filament just basically runs thermal.
 

trencheel303

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I don't think you can control the temperature the filament runs at as it's just in series on the circuit (there is no control gear or dimming equipment to otherwise limit power to the filament), it ballasts itself by means of its resistance increasing the more power is put through it, like any resistive load. That's why it's a self ballasted merc, the filament reaches its saturation and that stops the arc tube blowing up from power overload. They also reach near instant brightness so the filament just acts like a normal filament bulb.
 
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Cyparagon

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I don't think you can control the temperature the filament runs at

...

They also reach near instant brightness so the filament just acts like a normal filament bulb.
The arc tube voltage starts off very low, so the voltage/power/brightness of the filament starts off high. As the lamp heats up, arc tube pressure and arc tube voltage rise while the filament voltage and filament brightness drop. That's why you see a rather drastic color change as the lamp warms.
 

trencheel303

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Oh interesting. I noticed hardly any colour shift on my self ballasted merc so naturally believed that the filament stays a constant brightness, ie full brightness.

But then the more I think about it that indeed wouldn't be the case as doesn't the resistance of a HID arc tube drop as it warms, hence the very need for a ballast in the first place? I think this is why ballasts tend to be noiser at startup and then settle as the lamp warms too.

Sorry TLS; it appears you were correct!
 
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trencheel303

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bump.

I got myself something a bit special for the collection.



Yep, a lifeguard. Not just an ordinary coated one and thankfully not a Philips one either, but an early '80s /C. To the best of my knowledge, these are virtually unheard of in the UK, I don't even know if they're all that common in others' collections except for the diehards (of which I am not one of, I am just very fond of BT-25 and BT-28 Westys).

I managed to get it going, none of my E40 lamp holders would fit the mogul quite right and I was running wires from one of my existing lamp holders so it took a few tries to get a connection. Very nice light from it actually although the red band is a bit more muted than on DX lamps, and noticeably it takes a lot longer for the colour and output to stabilise than DX lamps, as apparently the C phosphor only works properly when the lamp is roasting hot.



I ran it a good 30-40 minutes (enough to scrub the arc tube as a few earlier false starts had caused some sputter, which I wasn't happy about on a NOS lamp) and then let it cool and gave the cap a polish with brasso. It came up beautiful.



Back in its packet and safe in the cupboard. I'm now looking at a clear top /DX version on ebay and potentially having a clear 175W sent over although the guy isn't sure about shipping it. I really *really* want a clear lifeguard, tbh.
 
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Sigurthr

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Wow, very nice find! Beauty of a lamp you got there. Don't mind ya bumping or rezzing this thread; I try to keep my threads rather informal as long as good content is being added. Practiced Forum Necromancers welcome.
 

Down with Umbrella

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Picked up a couple of these guys today at work for free. Some were still in the box. Haven't found a good ballast yet but the old ones say 250W. Also I pulled a few .35uf Capacitors From some of the older ballasts. They still look good.
I was told they were switching the Mercury vapor out for the sodium lamps But I was able to snag a few sodium lamps as well.
 
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joeyss

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Will these lamps light up under a plasma globe like fluorescent ones do.?
 




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