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SearsHome
Light Dimming on its own

I have a newly installed 600W dimmer and a newly installed 75W ceiling mount flushmount light fixture. When the dimmer is set at its lowest setting, the light brightens and dims on its own.

There are no other loads on the circuit at that time.

I am guessing that (1) one of the newly installed dimmers or lights is faulty; or (2) there is a loose or faulty connection.

Any ideas?

JLMCDANIEL
Re: Light Dimming on its own

Most likely you are at a low threshold level for the solid state dimmer and small fluctuations in the line voltage is causing the problem.
Jack

canuk
Re: Light Dimming on its own

It's not likely the lights themselves ... since it happens when set to maximum dimming I've seen many dimmers that have poor quality variable resistors ( the dimmer slider or rotating knob ).

If you have ever experienced a stereo with a scratchy volume control ..... corroded internal contacts within ..... similar thing with the dimmer....... rather than a scratchy sound there is poor resistance control for the internal SCR.

Providing the total wattage of the lights doesn't exceed the rating of the dimmer it could also be poor heat dissapation of the SCR.

Bottom line .... sounds like the dimmers are the problem.

SearsHome
Re: Light Dimming on its own

Thank you! The SCR is a silicon-controlled rectifiers in the dimmer itself? Just not sure of the terminology...

It sounds like I should start with replacing the dimmer. I installed Lutron Qoto Single-Pole Dimmers. They are 600W dimmers. They are fairly good quality dimmers; so perhaps it is a warranty replaced issue anyway.

If this does not work I will let you know. Thank you for the insight.

JLMCDANIEL
Re: Light Dimming on its own

One thing that is going to become more and more of a problem is harmonics caused by the use of more and more non linear devices such as Florescent ballasts, CFL's, and UPS's, and some power supplies. The harmonic wave form superimposed on the AC sine wave will play havoc with solid state devices such as dimmers.
Jack

canuk
Re: Light Dimming on its own
Quote:

The SCR is a silicon-controlled rectifiers in the dimmer itself? Just not sure of the terminology

Yep .... sorry about that.:o

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