strobing hps

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big vic

Senior Member
I have two 150 watt hps wall packs that are cycling on and off about every ten minutes. Changed the photocells and it still keeps doing it. There is no other lighting in the areas
 

barclayd

Senior Member
Location
Colorado
Do they cycle together? Are they old existing? or new?
HPS lamps tend to cycle on/off at end of life.
I'd say clean & relamp. If there are other, similar luminaires in the area of about the same vintage, you might consider cleaning & relamping all of them (group relamping).
db
 

raider1

Senior Member
Staff member
Location
Logan, Utah
Do they cycle together? Are they old existing? or new?
HPS lamps tend to cycle on/off at end of life.
I'd say clean & relamp. If there are other, similar luminaires in the area of about the same vintage, you might consider cleaning & relamping all of them (group relamping).
db

I agree, this sounds like the bulbs are near the end of their life and cycling due to that.

Chris
 

ActionDave

Chief Moderator
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Location
Durango, CO, 10 h 20 min from the winged horses.
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Licensed Electrician
Provided there is no problem with the circuit, any time I work on a HPS light it gets an new ballast kit and lamp and most likely a new photo cell. One trip and done vs. several to replace the next failed part.

If it is one of those shoe box wall pacs I just replace the fixture.
 

hurk27

Senior Member
Provided there is no problem with the circuit, any time I work on a HPS light it gets an new ballast kit and lamp and most likely a new photo cell. One trip and done vs. several to replace the next failed part.

If it is one of those shoe box wall pacs I just replace the fixture.

Sure hope you dont buy a new car because you get a flat tire:confused: replaceing a $100.00+ ballast because a $8.00 lamp is going out is kind of costly?
 
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hurk27

Senior Member
I have to take back some of what I said in my other post, I have to agree with your method if it is a fixture that is hard to get to such as ball field lights up about 90', or any other hard to reach fixtures that labor would out weigh the cost, but for the most part I don't get that many ballast ever fail, and while I have replaced starters and caps, they are more likely to fail because of poor maintenance of people letting bad lamps cycle when there at their end of life, I try to explain to owners and managers that letting a lamp cycle for very long can cause the starter to go bad because of the cycling of the lamp so it is in their best intrest to replace the lamp asap, although the starter is a solid state device and tend to be either good or bad, a EOL lamp can cause it to fail.
Caps are another item that rarely fail, and these along with the ballast I have found that most fail because of either a lightning strike, over voltage or an unsecured cover allowing insects and or birds building nest in around them damaging the windings, I did have one that some one previously didn't re-install all the heat shields back in the fixture causing a lot of heat damage to the wiring and components to which I just replaced the whole fixture, as for the photo cells, that would depend upon how hard the fixture was to reach, and if the element was pointed toward the sun (in a southern direction) as they tend to fail more often then if pointed north (not always possible)
 

ActionDave

Chief Moderator
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Location
Durango, CO, 10 h 20 min from the winged horses.
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Licensed Electrician
Then we agree much more than my other post may have indicated. Bug infested, bird nested or just plain ol' neglected, that's where I'm coming from. We used to repair rather than replace, but parts are getting cheaper and labor keeps getting higher.

If you are in a plant that has a good maintenance program or working with a familiar customer then changing the lamp or fixing the part makes good economic sense, but on a plain vanilla service call changing everything works out better for us.
 
Sure hope you dont buy a new car because you get a flat tire:confused: replaceing a $100.00+ ballast because a $8.00 lamp is going out is kind of costly?

It's economics.

Group lamp replacing have proven to be cost efficient, when you replace all bulbs at the lamps 85% life expectancy.

Depends on the circumstances a two-man-crew, a rented JLG or manllift cost could easily exceed $100 for the replacement of a single bulb. The cost per bulb gets drastically reduced when you change the bulbs all at once in an area.

So if you don't have a group replacement program and you change the bulbs as they burn out, there is some merit in replacing the ballast.

You don't find the fallacy of this approach until you look at the expected failure/life of a balllast. It is about 80,000Hrs for HID or about 4 times an HPS bulb. So the near perfect approach is to have group lamp replacement AND have group ballast or complete fixture replacement at every 4th cycle. Burning hours and environmental factors do affect the actual length of the cycle.
 
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