My daughter uses a special light for light therapy-- these are mainly used way up north (Like in parts of Alaska) for people who's bodies get "confused" because sometimes there is virtually no daylight for a long period of time. (It can cause severe sleep issues.)

The lights are expensive and someone else we know thought he'd like to have one but he wanted to make it himself (he doesn't have a lot of money).

I told him what sort of bulbs the light has and he headed on to make a similar light box for himself.

I'll leave out some strange details that got the partially built box in my hands to finish. Save to say that I'm already doing this for free so I'm not in a position where I need to go and buy parts-- I just need to know if this will work and if not, tell him what to buy.

Both my setup and his use two bulbs. These bulbs are U-Shaped with 4 pins on one end but the "U" is VERY tight-- both sides of the bulb together may be slightly over an inch and the gap between each "half" of the bulb is no more than 3/16 of an inch.

My bulbs are Sylvania DULUX L 55 Watt lamps FT55DL/841.

He got OSRAM DULUX L 55W 21-840's when he gave the supply shop the Sylvania number. If I'm not mistaken that makes the color temp slightly different (4000K vs 4100K). Probably not a real breaker.

They sold him a T5 Ballast by Damar PN: 26947A

My ballast is a Kesio Cat. No. A2100120

The form factors are quite different and though that doesn't always mean anything, his setup does not work at all-- not a flicker or hum-- nothing.

I wired this per the diagram on the T5. Have checked and rechecked it. Don't love his sockets-- they don't feel as tight as mine but I think the fit is acceptable-- just not as snug as I'd like, and it seems that if the sockets were too loose I could at least get a flicker or hum when I gently tap and wiggle the bulbs.

I have put his bulbs in my light-- they're fine. With a meter, I confirm that power is getting TO his ballast for certain. Also, with a meter, some power is getting to the sockets for the bulbs. I cannot seem to get a steady reading, but it is clear that power is there. Does an unsteady voltage mean anything? This is a "no load" reading anyhow...

Resistance on all filaments seems the same on my old and his new bulbs as well for whatever that may be worth... (Just over 2 ohms.)

Sorry for the long road to my ultimate question-- should this T5 Ballast work for my application?

The ballast in question only references the following bulbs:
F54T5HO, PLL55, PL50. I could be a hair off on those numbers as the text is tiny, but I think I have them correct. But who is to say if that is a complete list of applications or just the most common, and the 50, 54, and 55 make me think that is perhaps the wattage of bulbs that it is made for, and these are 55 watt bulbs...

This is one of those things where I thought the fellow just needed me to wire together the correct parts and now it has become a pretty big hassle, but he's a nice guy and he needs this thing working, so I'd really like to at least be able to tell him why this won't work.

Many thanks,

Richard H.

 

Does this fixture have a metal case behind the lamps that is grounded? Many of the new ballasts require the lamp to be near metal that is grounded or they will not start.

 

Yes, the case is metal and everything is firmly connected and well grounded. I have also double checked the path with a meter. Good idea but that's not the casue...

 

From what I read, the ballast in your friends' fixture is not operating properly. Probably a replacement will solve the problem.

 

If the bulbs and ballasts are not exactly matched then that is most likly your problem.

Puhaps that is why the OEM lights are so expensive....

In addition, until you match the lamps and ballasts, any further troubleshooting advice that we might possibly give is of no value.

 

Send me a PM to remind me at home ... I have a fixture that takes 2-55W CF bulbs. I recall a manufacturer's warning about an issue with how the pin sockets were wired so the full current was not routed through the pins, or something like that.

Maybe I can get a ballast nameplate photo for you.

 

Yes there are some issues with the 55W CFL but i am not sure what manufacter have the issue with this but as i know i allready ran into at least 3 allready so far this year [ gas station capanony luminaire ] so i have to replaceed with the MH and slove some quirks with it.

Merci, Marc