Reignition of a HPS lamp in a flood in the shopping center of Nesher city, « on: March 08, 2010, 07:55:13 AM » Author: dor123
http://www.youtube.com/watch?v=MQ5LFUPLV1s Warning: Picasa web albums are only visible with: Internet Explorer and Google chrome!!! The movie is blurred because of the digital zoom and the low resolution (320x240). This is a video of a cycling HPS lamp hot reignition and restrike in a flood in the shopping center of Nesher city. As you can see, the lamp flashs exactly like a xenon flash tube but with much lower intensity then the real thing. Have anyone ever saw such type of an ignitor start (Pulse start in US terms for MV and MH lamps) HID lamp reignition?
« Last Edit: May 02, 2011, 08:43:33 AM by dor123 »		Logged

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	Re: Reignition of a HPS lamp in a flood in the shopping center of Nesher city, « Reply #1 on: March 08, 2010, 01:41:55 PM » Author: Medved
This is normal hot reignition behavior of all pulse-start lamps, unless the ignitor has a timer pausing ignition attempts for given time after unsuccessful burst (5 minutes after 10seconds for HPS or 15minutes after 30seconds for MH ignitors). For successful reignition is not enough the ignitor break down the gas somehow. The pressure should be so low, the avalanche ionisation tahe place with given ballast OCV (=mains in EU). Timers are added to ignitors to avoid lamp electrode and ignitor wear, when it is not guaranteed, then the reignition would be successful.
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	Re: Reignition of a HPS lamp in a flood in the shopping center of Nesher city, « Reply #2 on: March 08, 2010, 02:03:35 PM » Author: dor123
I don't means ignitors timers. I means the ignition behavior. In most of the hot restrike videos i saw in this site, www.galleryoflights.org, www.youtube.com and also in private sites of lamps collectors and enthusiasts that contained videos of HPS and MH lamps hot restrike, the reignition was smooth and not pulsed. With the HPS lamps displayed a dim arc, sometime with a lightning shape, that was at permanent brightness or was increased brightness until the lamp restruck, or with the MH that streamers appeared coming from one electrode until a continuous dim arc is formed, the lamp started to flash randomally and the lamp restruck. I bet you was saw only the text and not clicked the link and saw the video itself.
« Last Edit: March 08, 2010, 02:42:36 PM by dor123 »		Logged

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Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

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	Re: Reignition of a HPS lamp in a flood in the shopping center of Nesher city, « Reply #3 on: March 08, 2010, 02:40:54 PM » Author: Medved
What i observe here (230V area, so series choke reactor ballasts - quite low OCV compare to CWA's used in US) some time (few seconds for HPS or minutes for MH) before successful reignition, is only dim glow (tiny sparks) with irregular flashes (the arc build up, but is not able to survive the current zero cross) and after some time in such "condition" it reignite to steady arc. In the video you posted only these flashes are visible and after few of them the steady arc build up. So in my eyes such behavior is normal here...
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	Re: Reignition of a HPS lamp in a flood in the shopping center of Nesher city, « Reply #4 on: March 08, 2010, 02:49:01 PM » Author: dor123
Hey! don't you saw that the flashes are at a regular speed (Exactly like a xenon flash tube)? This is because the ignitor are designed to make a pulses at a regular speed. There was several ignition attempts that wasn't producted a flash and so the lamp wasn't flashed then.
« Last Edit: March 08, 2010, 02:54:53 PM by dor123 »		Logged

I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the international date format (dd.mm.yyyy).

I lives in Israel, which is a 220-240V, 50hz country.

	Re: Reignition of a HPS lamp in a flood in the shopping center of Nesher city, « Reply #5 on: March 08, 2010, 03:12:49 PM » Author: Medved
Modern igitors make at least 2 pulses per mains period (one for each halfwave), some realy old ones make one pulse per mains period (only one polarity), what is all way much faster then these flashes. Ignitor pulses are seen only as the dim glow (one spark per pulse, but because of the frequency it look like steady dim glow). Tese flashes are the case, when ignitor pulses successfully start an avalanche ionization, but it is not strong enough to reignite by the ballast OCV after the current zero cross moment. So the bright discharge sustain only for about half of the mains period, causing such flash. This flash generate some amount of heat, momentarily pumping the lamp pressure up a bit, so next few mains cycles the avalanche ionization does not occur anymore, yielding quite regular (low frequency) flashes. As the average lamp mass temperature continue to decrease, the frequency of these flashes speed up. Only when the lamp cool down to so low temperature, so the OCV will be enough to reignite the arc even after the current zero-cross, the steady arc build up, so the reignition is successful.
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	Re: Reignition of a HPS lamp in a flood in the shopping center of Nesher city, « Reply #6 on: March 21, 2010, 08:09:29 PM » Author: arcblue
That kind of blinking makes me think the lamp is quite old. You are not seeing the individual pulses of the ignitor here, but rather the lamp starting a discharge but not being able to sustain it, so going out and then lighting again some milliseconds later (there are short cool-down periods in-between). Medved explains it better though. Usually the colour will be greenish-white (mercury) indicating sodium loss in the lamp. Some HID lamp/ballast combinations (and this goes for HPS, MH & MV) put on a real show at restrike, blinking and flickering wildly, sometimes for minutes. This usually seems to be the case with older lamps, but not always. Others simply cool down and strike the first time once they are ready.
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	Re: Reignition of a HPS lamp in a flood in the shopping center of Nesher city, « Reply #7 on: March 22, 2010, 08:08:02 AM » Author: dor123
arcblue: This HPS lamp in that flood is indeed cycling and it reach the orangey red of old HPSs before wenting out again. But the ignitor don't reignites it with HF pulses but with a speed of 3 pulses per sec, so each flash is actually an individual pulse from the ignitor that according to Medved successfully start an avalanche ionization, but it is not strong enough to reignite by the ballast OCV after the current zero cross moment. Several of these pulses are indeed invisible.
« Last Edit: March 27, 2010, 05:09:21 AM by dor123 »		Logged

I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the international date format (dd.mm.yyyy).

I lives in Israel, which is a 220-240V, 50hz country.