Author Topic: Old style FL dimming with starter transformers. is resistive baseload must?  (Read 1131 times)
Roi_hartmann
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Old style FL dimming with starter transformers. is resistive baseload must? « on: October 07, 2009, 12:15:08 PM » Author: Roi_hartmann
Hi everybody. I have not been around here for a while due to "massive overload of work" but I hope I can finally find some time to continue this great hobby. But to the point. Im about to instal old dimmer I bought, which is meant to be used with fluorescent tubes and starter transformers. I have one 2X36W fixture. I have installed starter transformer to that fixture and have not yet tested it. In the manual of the dimmer. there was this note that resistive baseload type xxxxx or 25W incandescent lamp should be used. Is this necessary or will it work without it?
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SeanB~1
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Re: Old style FL dimming with starter transformers. is resistive baseload must? « Reply #1 on: October 07, 2009, 02:00:29 PM » Author: SeanB~1
Most likely the resistive load is there to provide a path so that the dimmer can operate reliably and not flicker at lower power settings, or act erratically. Best to put one in, it will improve the control range and allow smooth operation. A 25W lamp could even be inside the fixture if needs be, provided it can dissipate the heat generated easily, and wiring near it uses high temp insulation.
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Roi_hartmann
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Re: Old style FL dimming with starter transformers. is resistive baseload must? « Reply #2 on: October 08, 2009, 12:38:14 PM » Author: Roi_hartmann
My starter transformer seems to be broken. lamps dont start at all. I would guess that there is partial short circuit because one of the ballast heats up pretty quickly after powered up. Becauso of that failure I modified that "rs-project"-fixture I made some time ago to fit for dimming. But could not find better transformer for cathodes so I used previous one. So now cathode voltage is 9 volt wich I think is too high. There was this chart in dimmer manual wich mentioned that cathode voltage to 20-40W "nomal lamps" should be 6,5V and for 65-80W should be 7,5. For rapid start lamps, voltage should be 20-40W 3,6V and 65-80W 5V.

I tested without resistive baseload and adjusting was no good at all. it started very easely flicker. btw, the tube I use is philips F20T12/cw ALTO.

And another question that came my mind. was how to adjust the "dimming level zero"(sorry I dont know right translation for this word) but there is mentioned in the dimmer manual, that as a factory defaults. this level(tiny adjustable resistor) is set for incandescent lamps and its need to be readjusted if used with fluorescent lamps, but there is no instruction for this. So any idea how this level should be adjusted? I remember once seeing instruction in somewhere else I just could not find them anymore. I post pics when I find my camera. lost that too
« Last Edit: October 08, 2009, 12:44:00 PM by Roi_hartmann » Logged

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SeanB~1
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Re: Old style FL dimming with starter transformers. is resistive baseload must? « Reply #3 on: October 08, 2009, 03:27:48 PM » Author: SeanB~1
That adjustment is to provide the level below which the lamp cannot be dimmed further. It is just there for convenience, and can be safely left where it is. Turn the control to lowest setting and then adjust the preset until the lamp is at the lowest brightness level you are happy to run it at ( or where it will start if power is applied when the lamp is first turned on with the setting at low) as the lowest light output. This does have a small effect on the operation of the dimmer if you go too far, but is not too severe.

Sad to hear of the camera, did it go for a long tumble from a tower>

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