Rewiring my Workhorse 5 ballast?

Hi, I've got a Workhorse 5 ballast driving a single 96 watt PC bulb.
It's turned out to be too much light for the tank, so I'd like to
drive the bulb at a little lower wattage. Unfortunately, I lost the
documentation that came with it, and I couldn't find the info I needed
on the Fulham website, so does anybody know how to rewire this ballast
to do this?

I'm assuming that I somehow would take only three of the wires and run
the bulb off those, but I'm unsure how to arrange this exactly. That
would be about 72 watts?

Also, if it's possible, this wouldn't damage the bulb, right? Might
it even increase its lifespan?

Thanks for any info!

Kristen

(Kristen) wrote:

96 watt bulb...
I'm assuming that I somehow would take only three of the wires and run
the bulb off those, but I'm unsure how to arrange this exactly. That
would be about 72 watts?

D'oh! Sorry to reply to myself, but I started out with the wrong "max
voltage" for my calculation. The max volts for this ballast is 128
volts. So that would be 2 wires for 64 volts. I would cap off two
wires, connect the remaining two together and run that into the bulb,
right?

And that wouldn't hurt the bulb, to run at 64 volts? Would it even
make it last longer?

Thanks,

Kristen

(Kristen) wrote ...
96 watt bulb...
I'm assuming that I somehow would take only three of the wires and run
the bulb off those, but I'm unsure how to arrange this exactly. That
would be about 72 watts?

D'oh! Sorry to reply to myself, but I started out with the wrong "max
voltage" for my calculation. The max volts for this ballast is 128
volts.

No the max WATTAGE of the ballast is 128W. The ballast is either a
120V version or a 277 volt version. Since I doubt you have 3-phase
service at your house, I assume you have the 120V version.


So that would be 2 wires for 64 volts. I would cap off two
wires, connect the remaining two together and run that into the bulb,
right?

Fluorescent lamps don't work that way. First off, the are current
devices, NOT voltage devices. Meaning, the ballast limits the current
to the lamp and the voltage developed across the lamp is whatever it
is. Without the ballast, the lamp would try to draw all the current it
could and blow up. The ballast's job is to limit the current to the
design specs for proper operating.

To dim the lamp you would need to figure out how to change the current
limit of the ballast. Maybe a different wiring diagram for a lower
wattage lamp will work, but only if that different lamp is SUPPOSED to
run on a different current. For example, the wiring for the 55W and
the 96W are the same because they use the same current. To do it
safely you would have to find out what the design currents are for the
various lamps and then wire up for one that used a lower current than
your 96W normally does.


And that wouldn't hurt the bulb, to run at 64 volts?

You don't have any control over the output voltage, so you can not set
it with the way you are thinking.

Patrick

Why not just change to NO bulbs? They are cheaper and the ballast is capable of
running a bunch of different bulbs in dofferent configurations. The web site
has a neat diagram engine.

www.fulham.com

(Paulio629) wrote:

Why not just change to NO bulbs? They are cheaper and the ballast is capable of
running a bunch of different bulbs in dofferent configurations. The web site
has a neat diagram engine.

I don't have the money to buy anything new.

Maybe I should just ask my father-in-law, since he's an electrical
engineer out of Standford...

Sorry I mixed up the WORDS volt and watt, Patrick, but it was the
middle of the night. You know I'm not stupid. :/

Thanks,

Kristen

On Thu, 25 Mar 2004 07:12:47 GMT, (Kristen)
wrote:

(Kristen) wrote:

96 watt bulb...
I'm assuming that I somehow would take only three of the wires and run
the bulb off those, but I'm unsure how to arrange this exactly. That
would be about 72 watts?

D'oh! Sorry to reply to myself, but I started out with the wrong "max
voltage" for my calculation. The max volts for this ballast is 128
volts. So that would be 2 wires for 64 volts. I would cap off two
wires, connect the remaining two together and run that into the bulb,
right?

And that wouldn't hurt the bulb, to run at 64 volts? Would it even
make it last longer?

I have a WH7... I assume the WH5 is configured the same way, except
with two "red" wires and the single "yellow" return wire.
Unfortunately, unless there's some magic behind electronic ballasts
that blows my knowledge of the theory out of the water, you can't
"underdrive" a fluoro bulb.

*Boring explanation for people to correct and poke fun at me with*
A ballast is basically a device to produce a high voltage jolt.
Electronic ballasts even more so. Upon startup, power builds up in the
ballast's coil and after a moment (ignore the reasons for it) it
HAMMERS that voltage into the circuit. End result is that my WH7 will
put out well over 700 volts when starting (this according to my volt
meter - I didn't take an exact reading). This jump in voltage excites
the electrons in the fluorescent bulb.. The jump is enough to cause
electron flow within the bulb itself and in effect "light" the bulb.
Once the bulb is burning, you could remove the ballast from the
circuit and just let the bulb run off your 120V house line (in theory,
anyways.. Unless you can unplug the ballast and make the power
connection at the speed of light it's not really likely).. The ballast
isn't doing anything (useful) once the bulb is burning.
So if you have a 96W rated bulb, then it's going to need exactly 96W
to keep it burning. Any less and you simply don't have sufficient
power to excite the happy little guys inside and you won't get light.
That's why the wattage always increments with bulb length - more space
in the bulb means more power needed.

Now, then, an easy solution would be to just buy your basic bulbs and
plug those in instead. Head to a hardware store and grab a couple cool
white bulbs and wire those in.. They'll work fine.

Now I need to find myself some 48" T5s.

Rikko wrote ...
*Boring explanation for people to correct and poke fun at me with*

OK I will go with a correction. I won't poke fun at you however.
smile

Once the bulb is burning, you could remove the ballast from the
circuit and just let the bulb run off your 120V house line.
The ballast isn't doing anything (useful) once the bulb is burning.

This is incorrect. The ballast plays a VERY important roll in that it
limits the current thru the lamp. Hence the name "Ballast" (like how a
ship's ballast regulates how deep in the water the ship sits). Without
the ballast, the lamp would appear as a short circuit (after it is
fired up) and it will try to pull as much current as possible and
obviously would blow itself up. The ballast keeps the lamp from self
destructing by limiting the current to the design specs of the lamps
it is designed to run.

PT

This brings up another subject... sort of....
Overdriving bulbs to *squeeze* a little extra out of them. If you havent heard
of read about this yet look here http://www.icecapinc.com/rev1.htm

and here

http://www.icecapinc.com/rev2.htm

also do some web searching. No I dont work for Icecap inc. I have tried this
but I used Fulham ballasts.