Buzzing dimmer switch

[Eigenvector]

Is it normal for a dimmer switch for a light to hum or buzz when turned on? My new dimmer switch is humming so I'm wondering if something was screwed up during the installation.

[Al Bundy]

"Eigenvector" wrote in news:J-adnaZakP2IP0PZnZ2dnUVZ [e-mail]:

First you say it's the light humming then you say it's the switch humming.

I've never heard of the switch humming.

I've heard lights and fans make a noise. Bet when the dimmer is all the way up there's no humming?

[CJT]

FWIW, mine don't.

Perhaps yours is heavily loaded (relative to its capacity) or overloaded, or poorly designed, or defective. There's not much that can go wrong with the installation.

Dimmers are cheap, so I'd probably replace it even if for no other reason than to eliminate the annoyance.

Are you sure it's the switch and not the lamp(s)? I don't think it's unusual for lamps to buzz when dimmed; dimming can cause thermal stresses that some lamps don't handle well.

[Chris Porro Email List]

i remember these cheap halogen lamps everyone had in college. those things all had dimmers and when you used them they got very loud.

my advice would be to demo some other dimmers at the store and find a quieter one. i'm thinking you most likey have a very cheap dimmer.

on another note, i'm a musician and doing some remodeling in my basement. in this search i discovered there are 2 very different ways that dimmers work. one quickly switches on and off the power (solid state), the other actually changes the voltage (variable power transformers). for muical purposes, that is, not having a buzz creep into your audio signal you want the later (variable power transformers). here is a link with more info then you probably care to read.

but if i were you, i'd just try and find a better solid state dimmer. the variable power tranformer type are more expensive and may require a housing. i have a solid state dimmer for 6 50watt lights in the kitchen and the thing is very quiet to the ear (although it does cause minor noise in my recording signal....a different issue you are not concerned with)

my 2 cents.

[Eigenvector]

A cheap dimmer, well that sucks! It is most definitely NOT the light that is buzzing, but the dimmer. I can hear it clearly when I put my ear to the wall next to the switch. Damn, I'll go shopping around tomorrow then.

On a second note, aside from the buzzing, is there anything dangerous about its condition, or is it simply buzzing because of cheap construction. I believe I understand how dimmers work, is it possible that the lights might also affect how it performs.

[CJT]

I doubt it's dangerous. Depending on the design, it might contain an inductor with an iron core that's mechanically not too stable, or some other component that is converting either a thermal or magnetic stress into noise.

[Steve B]

I had one like that. Humming was the last thing it before it exploded. I never figured out what happened because the pieces were so small. I just bought a better one, repaired the box, drywall, wiring, paint, and door jamb, and replaced it.

Steve

[Al Bundy]

CJT wrote in news: [e-mail]:

About 3 mos ago I tried testing a dimmer with a DVM before installing it. Nothing. Dead. I got another one. Put the DVM and analog on it. Nothing. WTF? I Put it in. It worked but yet NG with meters.

Now I am very curious as a lifelong debug method is out the window. I actually called the tech line at Leviton. Guy says yea you can't do that any more. The dimmers are all solid state. Nothing works until power is applied.

Maybe the WallyWorld is unloading all those dimmers with coils left on the planet :-)

[rickandroll]

[ppp]

In a solid state dimmer switch circuit the control is a timer circuit that sends pulses to a triac. The triac is normally OFF. Each pulse switches ON the triac to conduct electricity and light the bulb. During the dimmer LOW setting there are fewer pulses and therefore less current passes through the triac. At HIGH setting the pulse train is almost continuous and the lamp is at full illumination.

[Eigenvector]

See now that's what I would have thought. My dimmer is a solid state device so far as I know, it's not a rotary dial type rather its a 5 button selector style, off, low1, low2, low3, on. I doubt it has a core or a magnet in it as that wouldn't make sense. So that's why I asked, I can't see a solid state device buzz as there is nothing mechanical about it, the only thing I could think of was some sort of wiring issue.

[CJT]

I don't see why it wouldn't make sense. We're not talking about a transformer here, but a component of a filter that might be used to cut down on the RFI from all that switching.

[Tony Hwang]

Hi, Triac maybe loose on the heat sink.