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#32263 12/19/03 05:38 PM
Joined: Dec 2002
Posts: 228
J
JCooper Offline OP
Member
Hello and happy holidays to all. I have not really done anything related to lighting service but I have a friend who asked me to look at a metal halide light that keeps going on and off. It comes on and stays on for about a minute, then goes out for a few, comes on for another minute, and so on. Any suggestions on what to look at? I will take a look in the technical reference to see how these things are supposed to work. Thanks

Jim

#32264 12/19/03 05:41 PM
Joined: Jan 2003
Posts: 4,391
I
Moderator
Try a new lamp if it still does the same thing buy a ballast kit.

Do not leave a new lamp in place if it does not stay lit, you will just kill the new lamp.


Bob Badger
Construction & Maintenance Electrician
Massachusetts
#32265 12/19/03 05:46 PM
Joined: Dec 2003
Posts: 35
S
Member
You may also want to test the photocell on the fixture, if there is one....

#32266 12/19/03 09:22 PM
Joined: Dec 2000
Posts: 4,289
Member
Although it's not as common for MH lamps to do this as a High Pressure Sodium, it still happens.
Just replace the lamp...S

[This message has been edited by electure (edited 12-19-2003).]

#32267 12/19/03 11:39 PM
Joined: Oct 2000
Posts: 2,722
Broom Pusher and
Member
Sounds like an end of lamp life scenario.
Arc tube would be noticably darkened, or sometimes a bit warped.

Also may be an indication of:
<OL TYPE=A>

[*]Input AC Voltage Is Too Low,

[*]Incorrect Lamp / Ballast Matchup,
or,

[*]Excessive Heat Trapped Within Luminaire.
</OL>

Don't exclude a "Logical Paradox" setup between the fixture and a Photocell which controlls it! [Linked Image]
(Light from fixture shines on Photocell, Photocell turns off Lamp; No light on Photocell, so it turns on Lamp; Lamp produces light output which is detected by Photocell - Photocell turns off Lamp; No light on Photocell, so it turns on Lamp: Light detected by Photocell..... yadda yadda yadda!!!)
In BASIC, this would look like:

10: P AT 100: "Light On/Light Off"
20: GOTO 10
run
[Linked Image]

Scott35


Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!
#32268 12/19/03 11:44 PM
Joined: Jul 2002
Posts: 680
W
Member
Change the bulb, see this all the time.

#32269 12/19/03 11:46 PM
Joined: Feb 2003
Posts: 939
F
Member
also if this metal halide lumaire do have thermal protcter in the ballast housing ..

some "f" metal halide ballast do look like fluroscent ballast if so it will useally come with overheat protiectin in there.

i did see it happend when the insluation got too close to the ballast housing and do weird way .

merci, marc


Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)

#32270 12/20/03 12:00 AM
Joined: Dec 2002
Posts: 228
J
JCooper Offline OP
Member
I will look into replacing the lamp, it was in use for about a year, what is the average lifespan of the bulbs? If I remember correctly this unit is on 110, there is no photocell because this is an indoor installation. It is mounted right behind another much larger, I think about 250 watt this is a 90 watt, light, could heat be an issue? They are wall mounted in a rather large old warehouse, now an indoor rock climbing gym so there is also a lot of dust. I appreciate all your quick responses.

Jim

#32271 12/21/03 04:06 PM
Joined: Nov 2002
Posts: 267
W
Member
I use to go to a supply house, they had their own lamp tester. I don't think too many supply houses would bother investing in one these days because metal halide and hps bulb prices are so cheap now.


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