Running a 120V Load From a Fluorescent Ballast

Uh, since the ballast is fed with 120VAC, why even use the ballast?

Why would you need to regulate 120V if you have 120V in the first place.

This makes no sense. Why not just use a UPS?

You should be able to find something here...

http://www.ebay.com/sch/i.html?_nkw=++UPS++Battery+Backup+Power+Supply+&_sacat=0&_odkw=APC+Back+UPS+ES+500+Battery+Backup+Power+Supply+Plus&_osacat=0

If power fails to the fluorescent light, then its ballast is not energized, and thus not available as an emergency power source, anyway.

This is about when the bulbs fail and there's no replacement available. Not if the power fails.

A fluorescent light ballast is a specially engineered device to control the current flow in fluorescent light bulbs, you see gases don't conduct electricity in the same way as solids. One major difference between solids and gases is their electrical resistance (the opposition to flowing electricity). In a solid metal conductor such as a wire, resistance is a constant at any given temperature, controlled by the size of the conductor and the nature of the material.

In a gas discharge, such as a fluorescent lamp, current causes resistance to decrease. This is because as more electrons and ions flow through a particular area, they bump into more atoms, which frees up electrons, creating more charged particles. In this way, current will climb on its own in a gas discharge, as long as there is adequate voltage (and household AC current has a lot of voltage). If the current in a fluorescent light isn't controlled, it can blow out the various electrical components.

A fluorescent lamp's ballast works to control this. The simplest sort of ballast, generally referred to as a magnetic ballast, works something like an inductor. A basic inductor consists of a coil of wire in a circuit, which may be wound around a piece of metal. If you've know How Electromagnets Work, you know that when you send electrical current through a wire, it generates a magnetic field. Positioning the wire in concentric loops amplifies this field.

This sort of field affects not only objects around the loop, but also the loop itself. Increasing the current in the loop increases the magnetic field, which applies a voltage opposite the flow of current in the wire. In short, a coiled length of wire in a circuit (an inductor) opposes change in the current flowing through it (see How Inductors Work for details). The transformer elements in a magnetic ballast use this principle to regulate the current in a fluorescent lamp.

http://home.howstuffworks.com/fluorescent-lamp6.htm

Don't think your novel addresses, "what type of voltage regulator would stand up to the output of a fluorescent ballast for emergency lighting".

"Emergency" says it all. That means battery power. As in DC.

Looking for a way to juice up a standard bulb if the tube goes out and there's no replacements available. And removing or bypassing the ballast is not the option I was looking for as a replacement T8 will be reinstalled.

Don't be a fool. Just plug this in till you get a new bulb.

Now, you'll tell us there are no outlets???????????

Item Number: NAT40007

If there were outlets this question would have never been posed. Questions is not about finding options like "use a flashlight or find a candle". Question was not a riddle.

Just looking for a way to light up an incandescent bulb from a florescent fixture without removing the ballast.

If it can't be done, than the discussion is moot.

No problem. Sure you can. I'd use LED's though.

There are so many better ways to do this.

Hook the bulb up to the incoming 120v wires to the ballast. I think this has already been mentioned. Why on earth would anyone ever think of going to the other side of the ballast??

Because the end user would have to open the fixture. You realize some people don't even know how to remove a wire nut?

And how do they wire it to the other side of the ballast without opening the fixture?

As for wire nuts, is that the voice of experience? Hint: lefty loosy, righty tighty.

Yes. My experience has shown that many people can't even handle a wire stripper. My final design has to be "turn key" simple. You realize there's even some that can't install a fluorescent bulb no? My clients are not technical.

If the fluorescent bulbs goes, you can't simply plug in an incandescent bulb. To remove the ballast, you would need to take apart the fixture. Not an option for some people. The ballast takes control over the bulbs lack of adequate resistance. There's got to be a way to present a load and safely grab 120V from the outputs of the fixture.

Well, Mr. NY CLean Water,

You seem to be kinf of an a$$. For people replying to your amazingly detailless original post with a simple question, you rate their answer as off-topic. Now, after the 20-questions game, we finally find out specifically what you want to do (but we may not have the full picture even now, hmmm.)

What you are describing is not emergency lighting, but automatically-deployable backup lighting.

What I could/would do would be to have a load detection relay circuit tied into the primary of the ballast. When a drop in load is an indicator of a blown fluorescent tube, a relay switches power from the 120VAC ballast primary to a 100W incandescent load.

You'd better stock up on 100W incandescents before they dissappear from the market

Questions? Rebuttals?

I'll beat you to it and already mark this ass Off-Topic

Unless I'm being thick, Guv, you need to grab your 120V from the wires feeding the fixture. So why the hell are you messing about with the ballast?

If you want an emergency light that stays on when the power goes, don't mess about, just buy one.

Fluorescent ballast will generate high voltage ,as high as 1 kv during start up to ignite the FL tube. Is it easier just to tap from AC mains.

I know. This is why my original post mentioned voltage regulator. No one else really addressed it.

Bravo you think a varistor based circuit, feeding a drop down 120-15V transformer, into a rectifier to a 12V Reg would work to give me a constant 12V DC supply? Weighing all the options here.

How do you imagine that someone who can't even handle a wire nut will manage all of that other stuff?

This whole story is amazingly incoherent.

If you already have a 120v to 15 v transformer , why not just connect this trafo to the 120 v AC supply?, forget the ballast!

In that case, "flocking off" [as in #16↑] would seem to be the best thing to do with this post.

_{<unsubscribes>}