Ballast Energy Consumption

[barney12]

Hi, I am trying to determine the approximate energy consumption of the ballasts used with 400W light fittings. I am getting very different answers and hope that someone can help me. We have a few hundred fittings in our warehouse and we are considering replacing same with LED alternatives. To calculate the payback period I need to estimate the energy consumption of the exisitng ballasts.
We also have an area where the 400W lamps have been removed from the fittings. Will the energy consumption of the ballasts remain even though the lamps have been removed? Any advice would be very much appreciated.

 

[waross]

Don't confuse VA consumption with Watts consumption.
A 400 Watt ballast will consume a little more than 400 Watts. The VA consumption may be about the same for a high power factor ballast or quite a bit more for a low power factor ballast. The nameplate may show Watts in, or you may have to check the specs in the catalog. Use the nameplate Amps to calculate the VA consumption.

Bill
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"Why not the best?"
Jimmy Carter

 

[DRWeig]

Yes, do what Bill says -- check the data sheet for the ballasts you have.

Ballast will still use energy with no lamp attached, but not as much. This is often in the data sheet as well, or you can ask the manufacturer (or measure it yourself).

Rules of thumb for nowadays are 15-30W for high-efficiency electronic ballasts, 50-60W for standard magnetic ballasts (both for 400W metal halide) with lamp burning. I don't have data handy for no-lamp conditions. Here's a link to a chart with some typical values:

http://www.lithonia.com/Micro_Webs/PulseStart/default.asp

Good on ya,

Goober Dave