Slow cycling dimming of fluorescent cans

[e57]

I got one of these tomorrow.... 3 of 6 Fluorescent cans on the same Lutron Diva Tu-wire dimmers dimm slowly to ~70% then back up over a 5 minute period.

I would say the dimmer - but they are all on the same switch leg, only 3 of 6 do this.

Any ideas????

 

[LarryFine]

Nothing beyond swapping the CFL's around to see if the trouble stays with the cans or the lamps.

 

[e57]

No electrical defect found - two legs of a switch, one to one joist bay, one to the other, 3 cans each, same voltage, same current. But the cans having the problem have one differing factor - all in one joist bay have a cold breeze blowing through them from an opening under an over hang - no insulation either. So the temp of one set of cans is 65, the other effected ones is 45....

Plausable?

 

[captaincrab55]

Check the operating Temp on ballast...

 

[Dennis Alwon]

I got one of these tomorrow.... 3 of 6 Fluorescent cans on the same Lutron Diva Tu-wire dimmers dimm slowly to ~70% then back up over a 5 minute period.

I would say the dimmer - but they are all on the same switch leg, only 3 of 6 do this.

Any ideas????

I am confused as usual. If this is a 2 wire dimmer it will not work on CFL's or fluorescents of any sort. Diva makes one but I believe it is 3 wire and you need dimming ballasts.

 

[cadpoint]

hyperphysics.com

hyperphysics.com

Not for the Average guy!

Well here's the physic's of it, note that at the bottom page there's calculation that you can plug in the subjected numbers of your problem. Also note there is an Index to understand your terms. Hopefully this might help with understanding a 20?F seperation in your service. The Temp. is done in ?C.

http://hyperphysics.phy-astr.gsu.edu/Hbase/electric/restmp.html

This is was based on search for temperture coeffieient of resistance other related subject matter is available for viewing.

 

[LarryFine]

But the cans having the problem have one differing factor - all in one joist bay have a cold breeze blowing through them from an opening under an over hang - no insulation either. So the temp of one set of cans is 65, the other effected ones is 45....

Plausable?

To me, yes. You found a difference that you can eliminate. Pull out the can closest to the outside and stuff some insulation into the bay, and let us know.

By the way, do the three lights brighten and dim in unison, or independently?

 

[e57]

By the way, do the three lights brighten and dim in unison, or independently?

All 3 are the same bay, all have the same breeze. The install was done in the summer, and have been fine untill it got cold..... Really hard to tell about if in unison. The lighting goes on, and they with the other 3 start - gradulaly gain brightness to near full - the others continue to brighten, the 3 in quest never make it full bright, as they did before this recent cold snap.

Dennis - the Advanced ballast and 2X26 cfl lamping are listed compatable

 

[Dennis Alwon]

Dennis - the Advanced ballast and 2X26 cfl lamping are listed compatable

I am still confused. It may be the terminology. Are these CFL's or plc fluorescents. My understanding is cfl's fit into a standard screw in socket and the plc's are pin type bulbs.

The fact that the ballast and bulbs are compatable does not address the issue of the dimmer. Lutron Diva TU -wire dimmer. I assumed you meant 2 wire dimmer which is a standard dimmer but I am guessing that the dimmer is also a fluorescent dimmer.

Sorry for the misunderstanding.

 

[cadpoint]

http://www.advancetransformer.com/uploads/resources/hid-troubleshooting-guide.pdf
Advances High Intensity Discharge Lamp Ballasts has got a real good trouble shooting page on all there different types of ballasts.

About 36 is testing voltage. Along with end of life cycle issues per type of fixtures. About 46 is where you can read about inoperable ballasts.

 

[LarryFine]

The lighting goes on, and they with the other 3 start - gradulaly gain brightness to near full - the others continue to brighten, the 3 in quest never make it full bright, as they did before this recent cold snap.

That's gotta be it. If you don't follow my advice, above, then tell the customer they'll be brighter than the other three in the summer.

 

[e57]

That's gotta be it. If you don't follow my advice, above, then tell the customer they'll be brighter than the other three in the summer.

Thats kinda what I said... :grin: Insulation is not my forte / not my job... - and this is the same place I recently had to add heaters to because the lady under said lights was cold - so I'm leaving this to the GC to insulate and close the hole outside.

Dennis, I think CFL is becoming the general terminalogy for anything that isn't a t-5 or above. Got bent tubes about 6-8" long and goes in on one side - Call it a CFL....:grin: Why confuse the hippies right....
http://www.lutron.com/ballast/tuwire.asp
This is my guys right here - the one with the 50F start temp...
http://www.advancetransformer.com/eCatalog/out/4819160981.pdf