Fluorescent dimmers

Probably not. There's a limit to how low the ionization voltage level can be. Have you searched for a lower wattage bulb/tube?

Hmmmm if you were to make the ballast inductance variable to limit the current to differing degrees wouldn't that dim the fluorescent tube?

I'm sure I have seen very old lamp ballasts with an adjustable iron core to change the power level, maybe?

Guest said: "It is possible to adjust internally a fluorescent dimmer to obtain a lower illumination level?"

I assumed he had a dimmer that he wanted to adjust internally to get less light output, but after reading your post, I'm now not sure he does. There are a few economical fluorescent dimmers on the market (and some mighty danged expensive ones too ). I've used a few of these, but they're riveted together, and I suspect the internal circuits are not adjustable to further reduce the light output.

The way fluorescent lamps work requires a minimum ionizing voltage level, and once ionized, the thing has a negative resistance curve which used to be exclusively controlled by inserting a ballast inductor in the circuit upon reaching ionization. Some early dimmers used a multi-tapped ballast inductor to reduce current, and therefore ionization energy, to lower levels, but they weren't to popular. Others used rheostats in series with the inductors, but those weren't too popular either, as they produced a lot of heat.

Electronic choppers are typically used these days for fluorescent lighting fixtures designed for dimmability.

later . . .

Hmmm yes Bill, sometimes its difficult to tell exactly what the questioner IS asking about isn't it??!!

John

If you are wanting to dim lights with in easy reach there are plastic sleeves available with printed patterns to block out some of the light. You simply install the sleeve over the fluorescent tube. Then with the light on you rotate the sleeve until you reach the desired level of brightness. This is a mechanical fix with limitations. It does not change the actual output of the lamp. These are typically used around offices to reduce glare. I realize this is not the method you were asking about. I just like to keep options open when looking for a solution and thought I would extend the same courtesy to you.

Wouldn't it be easier just to purchase a multi-tube fixture and simply switch off some of the tubes?

I religiously subscribe to the KISS principle.

provided the ballasts were also switched out of circuit. I remember fitting a different (larger) capacitor in an 8 foot fluorescent, it got incredibly bright. I didn't leave it running for long, it scared the c**p out of me.

Some fluorescent dimmers do have a trim pot on them to set low light level, usually accessed through a hole in the yoke (heat sink) but that will only work if the dimmers been adjusted up. The minimum dimming level is a function of the ballast, there are 1%, 5% and 10% ballasts, the percentage being the % of light at low end. So you may want to look at the ballast and determine what the minimum light level the ballast will give you.

Shawn

KinoFlo Fluorescent Lights have been in service to the Motion Picture Industry since the late eighties and early 90s, and are wonderful as they produce a soft light, without much heat, plus they can be dimmed. I don't know how they made these lights, but they are great. Optima 35 tubes are Tungsten Balanced tubes, and Chroma 50s are daylight, at least they were last I was working sets. The tubes are expensive, but the quality of light is superior to run of the mill fluorescents. In one case I put neutral density gels around standard fluorescent lights that were in a cove, so to get the bar lighting acceptable. Lee, Rosco, and GAM are manufactures and suppliers of lighting Gels, used to alter the color, or color temperature of lights. GAM produces and supplies sleeve gels specifically made to easily slide over tubes. If cost is an issue, and this is a application problem, I suggest the Gels. If you are desiring to create a product, as an option for Bars, and Resturants which will stick with dimmable lights, so CFLs (compact florescents) can compete there, you are on a profitable track should you create one of reasonable price for that application.

Hello guest,

can you tell us if you want to 'dim' the main florescent light or, did the switch or light controller switch either remotely or on the wall?

babybear