Electric peeps - ballast question
 

I think I know the answer, but I want to confirm.

I have a couple of Workhorse 5 ballasts in a single box. They are 128 watts "maximum power output" and are described to operate 1-3 39W T5 bulbs each.

Does that mean if I run:

1-39W bulb it will be over-driven at 128 watts?
2-39W bulbs will be over-driven at 64 watts each?
3-39W bulbs will be operated at 42 watts each?

Or is it not that simple? I imagine the ballasts will not pull exactly 128 watts...?

Means if your ballast is rated @ 128watts and you run 1 39watt t5 the ballast will run a lot cooler and last much longer than if you ran 3 39 watt bulbs which heats up the ballast much more. The higher the load/bulbs used the harder the ballast has to work to fire them. :amen:

It won't overdrive if you connect as directed, regardless whether you run 1, 2 or 3 bulbs (not sure you can run just one bulb though). The ballast will pull the power needed to power only the bulbs connected plus a little more depending on the power factor.

I think this may have been true with the older magnetic ballasts but I'm not sure if this is the case for the small electronic ballasts.
From my experience with fluorescent lighting, if a ballast is trying to fire a lamp that is faulty or not there, the ballast will eventually fail. Same with HID.

Fluorescent lighting "general". 39W lamp will draw 39W until it gets older, then I'm told it will draw a bit more. Over ballasting a lamp will cause the lamp to burn out quicker. Using a 2 or 3 lamp ballast for a single lamp will cause the ballast to fail quicker.

I have never used the workhorse series of ballasts, they look adaptable to different situations. Probably more expensive and why I don't see them on jobs. If you can find the right wiring diagram for what you want to set up I'd go with that. Wiring diagrams should be on their website.

Ok, so it's not like halide lamps which the ballast puts "X" watts into the bulb. T5 draw the power they need rather than receiving whatever is given.

Straight from the Fulham website, I can find wiring diagrams for the Work Horse 5 for both 2-39W bulbs and 3-39W bulbs (not for just one). I don't see anything about their recommended combination - maybe I will email them.

Given the information you guys have provided though, I would be best off running 3-39W lamps on each of these ballasts?


What do they mean by "for linear lamps use a starting aid"?
http://www.fulham.com/images/WDgifs/wire9.gif

http://www.fulham.com/images/WDgifs/wire8.gif

I think a starting aid is just grounded metal down the length of the lamp, within a half inch or so. Usually just the metal body of the fixture, haven't heard that term I a while... It will help draw the electric arc down the length of the lamp to the other end while it's trying to start.

Are you able to post a pic of the ballast?

Just looked at the website. They probably don't show the wiring diagram for a single lamp because most people would buy a smaller ballast if they wanted to run 1 39w lamp. It would probably work using 1 of the red leads, but I would e-mail manufacture to be sure.

As for how many lamps you want to run on each ballast? Should get rated life of ballast with 2 or 3 lamps. Slightly more electrically efficient with 3 lamps but negligible considering everything else we have in our tanks.

I used a couple of Workhorse 7 or 8 ballasts to overdrive some 48 inch T5HO tubes. They're great ballasts and very flexible in their ability to run different tube combos. I have some additional data saved on a hard drive. Along with the diagrams, which you've found, I also have a chart showing all the Workhorse ballasts & what tube combos you can run with them.

Still have the ballasts somewhere in the basement, need to wade through the junk & find them. Got some stuff going on this evening, but I should have more info for you tomorrow. Basically it comes down to not exceeding the rated wattage of the ballast by using the correct number of wires for the bulb combo you wish to run. I played around a bit with hooking up extra wires to overdrive my tubes.

Thanks Mike, I was hoping you would chime in! I'm not sure that I want to intentionally overdrive the bulbs - I just want to know if that will be the case before finishing up my designs for my new T5+LED custom combo fixture. :lol: