Very basic Fluorescent lamp/ballast power consumption question

[pasd1977]

Apologies if this question is too basic for this forum, but any help would be appreciated:

I am trying to determine the probable power consumption for the following: 4 x 60" (F60) High Output lamps. I have read around as much as possible and found this page

http://67.19.219.136/en/lighting/HOF_signballasts.aspx

my interpretation is that the 472 model (second table) would be suitable for 4 lamps totalling 20' and that it would consume 312 watts.

Are my assumptions correct? I am looking for general figure (to use in some calculations relating to power use in outdoor backlit adverts).

Thank you again, Patrick

 

[mc5w]

Sign ballasts are designed to give you almost constant current over the range of total lamp length specified. They are generally designed to give you 100% ballast factor ( actual light output versus a theoretical laboratory ballast ). They are NOT designed for the best efficiency but rather to provide full power to the lamps particularly during cold weather.

The only way to measure the power consumption is to build your sign and then hook up a wattmeter. You would then need to run the test at several different temperatures from -20 degrees Fahrenheit to 100 degrees Fahrenheit.

Mike Cole. mc5w@earthlink.net

 

[mc5w]

I forgot to mention that the sign ballasts are designed to tolerate the capacitance of extra long leads that are needed when wiring a sign.

Advance makes an electronic high output ballast that will give you 89% to 115% ballast factor for 1 or 2 lamps with a total length of 8 to 16 feet. You might be able to use this in place of the sign ballasts if the red leads do not extend more than 20 feet and the other leads do not extend more than 5 feet.

However, you might have to use the electromagnetic ballasts if itnturns out that your wire lengths are longer.

 

[pasd1977]

Thanks very much for your help mc5w. I still have a few questions you, or someone else on the board, might be able to help with:

What I am trying to do with these calculations it work out the likely (not exact, but a reasonable estimate) power consumption of a series of bus shelter type backlit advertising boards which I am looking at the costs of. I do not have direct access to the suppliers/manufacturers as I am not involved in the project. What I do know for sure, from speaking to a helpful guy at the company that designs these signs is that:
a) They use four 60" HO lamps running vertically.
b) They use a 'standard' ballast.
c) The company that does the manufacturing links to Allanson Lighting Electrics as a supplier, so I am assuming that they use their ballasts.

From there I do some more research and find this page

http://67.19.219.136/en/lighting/HOF_signballasts.aspx

which seems to tell me that the Alanson 472 would be an appropriate model and that it has an input watts value of 312W.

Temperature variability, as mentioned by mc5w, may also be a significant factor here. These signs are located outdoors in Toronto, Ontario. Mean minimums here hover around or below freezing for 5 months of the year.

What I am trying to determine is this: Based on all of the above, is it reasonable for me to use 312W as the power consumption of the lamps/ballast for my calculations? If it isn't and there are too many conmplexities, is there some rule of thumb I can apply or other methjod of getting a useful power consumption to work with without having access to the signs or their electrical specs?

Again, Any help very much appreciated.

 

[RonShap]

Use the ballast input power rating 312W.