flourescent ballast question

[battlelance]

I have a two-lamp ballast, and I'd like to modify the wiring so I can
run either one, or two lamps. Right now, if I remove one of the lamps,
the other lamp shuts off.

From the looks of it, they would be wired in series. Do you think I
could wire it in parallel without having the ballast explode or burn
down my house?

TIA

[Bill Kirkpatrick]

Depends on your ballast. Generally speaking, if it isn't
electronic - no way. Then, generally speaking, if it is
electronic there's no certainty either.

My IceCap does 2, 3, or 4 bulbs, but not 1.

In any case, even if the ballast does support alternative
wiring, it is most unlikely you will be able to select 1 or
2 bulb operation simply by installing 1 bulb or 2. It will
be a choice made in the way it is wired.

Now, some ballast types will keep 1 of their 2 bulbs "lit"
when the other is either missing, or burned out in certain
ways. "lit" doesn't mean good. The remaining bulb is
subject to burning, and the ballast is subject to
overheating. It is a failure mode, not a neato
configuration feature, and surely not one you want to run
with as standard operating procedure.

But today is a wonderful world. Look for the Manufacture's
sticker and give them a call.

******************************
battlelance wrote:
> I have a two-lamp ballast, and I'd like to modify the wiring so I can
> run either one, or two lamps. Right now, if I remove one of the lamps,
> the other lamp shuts off.
>
> From the looks of it, they would be wired in series. Do you think I
> could wire it in parallel without having the ballast explode or burn
> down my house?
>
> TIA

[Rikko]

On Thu, 05 Feb 2004 16:32:13 GMT, battlelance
> wrote:

>I have a two-lamp ballast, and I'd like to modify the wiring so I can
>run either one, or two lamps. Right now, if I remove one of the lamps,
>the other lamp shuts off.
>
>From the looks of it, they would be wired in series. Do you think I
>could wire it in parallel without having the ballast explode or burn
>down my house?

Find the exact model of the ballast and see if you can find a
manufacturer's site. A load sensing ballast should compensate for
whatever amount of lamps you have hooked up to it.
You may want to check the available wattage first, however. It's been
far too many years since high school electronics, but you may find
that having 2 lamps connected in parallel will draw more power than 2
lamps in series - or they might not light at all. If you end up trying
to draw too much power (ie. 2 x 20W lamps from a 4-24W rated ballast),
something bad will happen.

[Harry Muscle]

"battlelance" > wrote in message
...
> I have a two-lamp ballast, and I'd like to modify the wiring so I can
> run either one, or two lamps. Right now, if I remove one of the lamps,
> the other lamp shuts off.
>
> From the looks of it, they would be wired in series. Do you think I
> could wire it in parallel without having the ballast explode or burn
> down my house?
>
> TIA

If your goal is to control which lamp is on via a switch, it's going to
prove a lot more difficult that it looks at first. I looked into such a
design a little while back. The biggest problem with using a switch to turn
the bulbs on or off is that there is sometimes almost 600V between the
ballast and the bulbs (sometimes even more, upwards of 1300V, depending on
the ballast) Finding a switch or relay rated for that can prove expensive,
usually more than simply getting another ballast (ie: having two ballasts
for two bulbs).

Harry

P.S. Ballast are a lot more complicated than most people realize. As far
as I'm aware, I have never heard of a ballast that's designed for either
series or parallel connection, it's always one or the other.




-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

[battlelance]

On Mon, 9 Feb 2004 10:00:17 -0500, "Harry Muscle" >
wrote:

>If your goal is to control which lamp is on via a switch, it's going to
>prove a lot more difficult that it looks at first. I looked into such a
>design a little while back. The biggest problem with using a switch to turn
>the bulbs on or off is that there is sometimes almost 600V between the
>ballast and the bulbs (sometimes even more, upwards of 1300V, depending on
>the ballast) Finding a switch or relay rated for that can prove expensive,
>usually more than simply getting another ballast (ie: having two ballasts
>for two bulbs).

Your right... The reason I haven't replied to this thread for a while
was that I was doing some research, and the switch issue you mention
was exactly the item that stopped me in my tracks.

So, I took the ballast out of the hood, mounted it in my garage, and I
now have a nice new light.

I picked up one of those Hagen Glomat 2 thingies, and now I can run my
25w T-8 marine glow lap, or my T-12 30w GE cool white lamp, or both -
all I have to do is yank off an end cap. As a bonus, my hood is now
5lbs lighter, and 10x cooler than it was before. All for $40.

I'm happy, my fish look great, and no one got electrocuted! :)