Dimming Quickstart Circuits

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Dimming Quickstart Circuits

Post by SuperSix » Fri Mar 04, 2011 11:40 am

I thought I might as well post this in case anyone's interested in having a go!

I've done some experiments dimming fluorescent tubes on circuits not designed for dimming. To my surprise I've had great success with dimming quickstart circuits. I've found that by using a phase control dimmer suitable for inductive loads you can dim down fairly low before any problems occur. As the tube dims the quickstart transformer seems to compensate and starts heating the cathodes, the further you dim down the higher the heating current seems to be.

I've had even greater success using a rheostat, you seem to be able to dim right down to a uselessly low light level without any problems with flicker and the tube will even start on the lowest setting as quickly as it would normally.

I know normally you need a cathode heating transformer on a separate supply to the choke so the filaments are continuously heated the same as a US rapid start circuit but this seems just as good.

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Re: Dimming Quickstart Circuits

Post by Tom » Fri Mar 04, 2011 3:04 pm

That sounds very intersting! I would have never guessed this worked without a proper dimming transformer as mentioned. My old boss at a disco shop where I used to work did something similar in the early 80s running 4' coloured tubes from a 'Sound To Light' controller in modified Pop Packs with Transtar ballasts! I never saw them working but I'm sure it looked awesome! I think the controllers were Pulsar Zero 3000s! 8-)

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