Flourescent Lighting Question

[Shray]

Hello, I am a Plant Engineer at a Factory in which money is very tight ( like everywhere else ha ha) My question is regarding lighting. Many areas of our facility have Flourescent F34 T12 Philips Alto 4 bulb fixtures with older Magnetic Ballasts in them. As a controlled test our electricians in one small quadrant replaced the bulbs and nothing else with F32 T8 Philips Alto bulbs. First, I must say I was surprised that the T8's fit in a T12 fixture but they do, the T8 just has smaller diamter pins. My question is, I am getting more light out of these bulbs then the T12's. I realize part of this is the light output degradation over time. But am I degrading the life of the existing ballasts or fixtures by running these T8 bulbs in these old T12 fixtures ? 2nd question is am I actually saving some electricity or is the old ballast just driving these T8 bulbs harder and perhaps going to make them die a quicker death..... Looking for input from any lighting experts. Thanks very much !

 

[EEJaime]

I've not seen this combination actually work before, so I am somewhat surprised it is working. Your higher light levels are probably due to just having new lamps. I don't know what color temperature lamps the T-8's are, but that may add somewhat to the perception of added lighting. The socket-pin interface can be a problem as you will not get a good connection which will cause arcing and heating of the pins. Not to mention you probably don't have an installation that any manufacturer will back up and I think your lamp life will suffer.

Some "fixes" may work for a while, but in the long run may cause more problems and costs than you are saving. The t-8's have specific Lamp/Ballast combinations which result in the lower energy usage, especially with electronic ballasts,so I doubt you're saving any energy at all with the old magnetic ballasts.

 

[burnt2x]

I haven't used much Philips units but I do know GE has recommended ballasts for its T8 tubes (see attached).
Try googling "approved ballasts for Philips T8"
Glad to be of help.

 

[jbelectrical]

The increased output can be attributed to the following:

-The T12 ballasts are overdriving the T8 lamps.
-T8 lamps, by design, possess a higher lumen output than their T12 counterparts of similar length.
-The T8 lamps are new and have not suffered from lumen depreciation.

Anyways, I hate to repeat something that another person has already posted, but T8 lamps are best suited for high-frequency, electronic ballasts. Since the T12 ballasts are overdriving them, as you already pointed suspected, lamp life will be reduced. Ballast life should not be compromised, however.

As for any energy savings, the ballasts' input wattage should remain the same.