Author Topic: Dutch MV lanterns  (Read 1995 times)
Raphael
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Dutch MV lanterns « on: March 10, 2009, 02:50:37 PM » Author: Raphael
Sadly they're gone now.  :'(

All that's left is this:

http://www.youtube.com/watch?v=OZaAG3NrC5Y&feature=channel_page

http://www.youtube.com/watch?v=9Jog6CtBPc0&feature=channel_page
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Mercury Man
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Re: Dutch MV lanterns « Reply #1 on: March 27, 2009, 12:01:51 AM » Author: Mercury Man
What was causing the lamps to flicker like that before they went out completely?  I've never seen a fixture with TWO MV lamps in it!!!  And why were they taken down?
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TudorWhiz
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Re: Dutch MV lanterns « Reply #2 on: March 29, 2009, 04:53:20 AM » Author: TudorWhiz
What was causing the lamps to flicker like that before they went out completely?  I've never seen a fixture with TWO MV lamps in it!!!  And why were they taken down?

Actually Brian, MV, HPS, fluorescent, and gas related lamps (except anything electronic ballasted) flicker 60 times per second or in this case 50 times per second....but most human eye can't see the flicker....) So the movie was a low frames per second also camera can see it...if you use your camera at a MV lamp and hold the shutter lightly (it may also depend on the camera model and brand) you'll see them flickering on the camera screen..but not your eye...that is because of the "flashing 60 times per second (or 50) so thats the flash pattern...

So understand that your eyes don't see flicker (well sometimes you'll see a flicker on your corner of your eye) but the camera with slower frame per second can catch all the flickering....


Also for the "2 lamp thing" is common in European area.....notice one lamp is dimmer than the other? it's all like that because the dimmer one is on all night long while the brighter one would be on at a certain time...like during rush hour but at midnight or something like that when most people are sleeping its turned off......so the dimmer one is used more....making arc tube blacken....



« Last Edit: March 29, 2009, 04:55:40 AM by TudorWhiz » Logged

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bluelights
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Re: Dutch MV lanterns « Reply #3 on: June 04, 2009, 03:30:39 PM » Author: bluelights
Actually Brian, MV, HPS, fluorescent, and gas related lamps (except anything electronic ballasted) flicker 60 times per second or in this case 50 times per second....
Actually it is 100 or 120 times per second because the arc fires on every half-wave of the mains waveform.
The interference is the difference between camera's frame rate and the lamp flicker, while taking in account the harmonics, so with a 30fps camera and a 50Hz bulb which flickers 100 times a second, you'll see a 10Hz interference (the third harmonic of 30Hz is 90Hz which is the closest to the lamp frequency so the interference is 100-90 = 10hz flicker on the camera).
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TudorWhiz
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Re: Dutch MV lanterns « Reply #4 on: June 08, 2009, 08:00:04 AM » Author: TudorWhiz
That sure makes sense...

But here's another thing that J-frog (Jeremiah showed me) that a HX ballast and a CWI/CWA ballast flashes differently. what would be happening here?
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bluelights
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Re: Dutch MV lanterns « Reply #5 on: June 12, 2009, 03:33:55 AM » Author: bluelights
That sure makes sense...

But here's another thing that J-frog (Jeremiah showed me) that a HX ballast and a CWI/CWA ballast flashes differently. what would be happening here?

It's because the current waveforms are different, HX has a current pattern which is close to wine wave and I believe CWx has more "spikey" current so the flashes would appear a bit shorter and more intense.

But again I have never used a CWx ballast, I just know how does a current waveform of a MOT and series capacitor look, which is kind of similar to CWI.
« Last Edit: June 12, 2009, 03:35:32 AM by bluelight » Logged

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