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humming halogen monorail lights when dimmed

Posted by farmgirlinky (My Page) on
Mon, Dec 27, 10 at 21:20

Hello, all

the Edge Lighting monorail lights are up in our new kitchen, which is getting closer to completion; only a couple of anxiety-provoking maneuvers remain. But here's the thing: when we dim the monorail lights -- with halogen bulbs in the heads for now -- they hum! It's not horrible, but audible when there is no other background noise such as the radio. The electrician says the filaments in the heads are vibrating when they bulbs are dimmed. Any solution for this?

Thanks,
Lynn


Follow-Up Postings:

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RE: humming halogen monorail lights when dimmed

The electrician is right. Try different brands of bulbs.

The problem is the way a thyristor dimmer distorts the AC waveform. Sine wave dimmers don't do that and they're becoming more widely used in theatre, but I don't know of any yet made for homes.

Autotransformer dimmers would eliminate the hum, but they're hard to find, large, and quite expensive.

You can also minimize the hum by sizing your lights (or switching some off) so they run at or near full brightness most of the time.

Finally, LED lights don't buzz. But they're still quite expensive and limited in selection. They're more efficient than incandescent, but those currently available are not as efficient as fluorescents.


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RE: humming halogen monorail lights when dimmed

Those are typically low voltage MR16 lamps. Make sure the dimmer is compatible with the transformer.


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RE: humming halogen monorail lights when dimmed

Right: low voltage MR 16 lamps they are. I think we now have Leviton dimmers in place, on a gang of five switches. Thanks for the dimmer advice -- I think we should try the Lutron C-L Diva dimmer, which supposedly is compatible with both halogen low-voltage and dimmable LEDs -- or even a mix of the two? -- that way we can phase in LEDs as their light quality improves and they become less expensive. Thanks for setting me off on this track.
Lynn


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RE: humming halogen monorail lights when dimmed

I had this problem a few years ago. We tried changing bulbs and dimmers but the humming continued. We had to change the magnetic transformer to an electronic transformer, at an additional cost, but it fixed the problem.


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RE: humming halogen monorail lights when dimmed

Thanks to davidr, spotted cat, dim4fun for your good advice. We have improved the situation a good bit by changing the dimmer to one by Lutron that is intended for either dimmable halogen low-voltage lamps or for dimmable LEDs. I'm hoping that the latter soon are available at a good price and with high-quality light: that should solve the issue completely. I haven't yet investigated the potential for change from a magnetic to an electronic transformer; the hum will have to be bother me more before I contemplate additional investment, I guess!

When oh when will LEDs be ready for prime time, with warm light and good spill etc.?

Another issue: these Edge "Harley" halogen/LED compatible monorail heads are designed so that there is "spill" up toward the ceiling, which I love. Looking at the existing LED bulbs, it doesn't seem likely that they will spill light out the back of the lamp. What do you think?

lynn


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RE: humming halogen monorail lights when dimmed

I have yet to see an LED light which is truly omnidirectional. All of the existing ones I know of radiate mostly or entirely in a rather narrow beamspread.

I don't think an omni LED is going to happen any time soon, if ever. LEDs are directional by nature.

Part of the reason is their size. The dies are small, and they generate a surprising amount of waste heat when producing substantial luminous flux. Getting rid of that heat so they don't burn themselves up generally requires that they be attached to something big and metallic - which if nothing else tends to block the light in at least one direction.

It's something of a miracle that the manufacturers have been able to make LEDs work as well as they do for area lighting. They are sort of out of their element.


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RE: humming halogen monorail lights when dimmed

Thanks, davidr,
a girl can hope
lynn


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