Humming led light with dimmer

Friend of mime installed a led ceiling light. It's fine until he put a dimmer on the switch. Now it's humming like an old Florence fixture, only louder. Any easy way to fix it?

Reply to
edward.ming.lee
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Have you tried taking the dimmer off?

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Rick C
Reply to
rickman

Yes, then the humming stop. Question is anyway to fix it with the dimmer? Dimmer is probably chopping up the input source to the led regulator. But what's causing the noise?

Reply to
edward.ming.lee

Some LED lights are rated for use with dimmers and some say non-dimmable. So is his fixture for use with dimmers?

Dan

Reply to
dcaster

It works, but too noisy. He is using a digital dimmer with remote. Perhaps he need a different type. He prefers to change the dimmer (5 minutes) vs. the led chandelier (5 hours). Yes, we spent 5 hours installing it.

Reply to
edward.ming.lee

Currently using this from home depot: Lutron Caseta Wireless 600/150-Watt In-Wall Dimmer with Pico Remote Control Kit

Reply to
edward.ming.lee

The dimmer is likely a phase control dimmer which turns the power on into each half cycle so there is no power being delivered during much of the cycle. The caps in the LED lamp might not be large enough to support the LED for this amount of time and so the LED turns off. If there is an inductor in the LED it is being pulsed at 120 Hz with the abrupt edge of the AC line when the phase control turns on giving a mechanical pulse and causing the sound.

A bit of speculation, but there it is. Does the hum sound like 120 Hz?

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Rick C
Reply to
rickman

The LED lamp probably has a DC converter in it. That means you are now driv ing a semi capacitive load.

Dimmers reduce the DC peak voltage, but the current, not so much. Incandes cents were mostly resistive so it was not a problem. The resistance might h ave went down, but it was still mainly resistive and with a teeny bit of in ductance thrown in.

They need to have a high speed chopper dimmer. Maybe they do, I haven't loo ked. The technology certainly exists. But regular dimmers chop at the line rate. It is probably literally the wires vibrating inside the fixture.

You might try some series inductance but I have no idea how much. You have to pick a value that will not have too much loss, yet smooth out the curren t i.e. get rid of the big spikes. You can't even figure that out with a deg ree without all the parameters. Like the total wattage. And then, the induc tor might hum. And you are not getting one big enough that is air core with out a ton of money. I found that out o speakers. The best coils for use in speakers are air core because they do not saturate easily.

I found out quite recently that they actually do but I don't see how, what the permeability or whatever goes from that of air to what ? A vacuum ?

I would talk to the people who sold all this stuff. Others have no doubt al so had this problem so there may be an off the shelf solution and for the w ant of a few bucks and changing the dimmer it could be solved.

I've had the hum problem with incandescents actually. The hum went away whe n it was all the way up, but that did not suit my purposes. I put 300 watts worth of them into the light so that I could see when I wanted to, but kee p it dimmed usually when I was just surfing or whatever. (there was alot of whatever back then)

If it was a store, pick up the phone. If it was online there may be a FAQ a nd if not you might be able to email them. They might just say "Oh, you're using the wrong dimmer for these, you need...".

Reply to
jurb6006

More important is the lamp. You are tossing the dimmer. What lamp is it?

I've tried a number of times to find LEDs that are compatible with dimmers including once when I bought an LED which had specific recommendations with part numbers and I bought one of the part numbers. The LED and dimmer still didn't work well together. I've never had one make noise though. That's the domain of old fluorescent fixtures. I have one in my kitchen that hums. I guess it doesn't know the words.

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Rick C
Reply to
rickman

Don't know much about the lamp. It's a $3000 custom (or limited edition) chandelier from Italy. Not going to open it up to check.

Yes, it does sound like 60/120 Hz humming.

Reply to
edward.ming.lee

maybe with a different dimmer?

film cap? inductor?

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Reply to
Jasen Betts

** No easy way.

It's not really a "celing light" - is it?

It a flaming great chandelier.

If you really need to dim it silently, replace the dimmer with a Variac or a sine wave dimmer.

.... Phil

Reply to
Phil Allison

If you don't know anything about the LED lamp, how do you propose finding a compatible dimmer? Can't you contact the maker?

BTW, I bet they are using a $10 Chinese lamp module. The $5000 was for the bling. You are probably better off buying new guts and retrofitting with something that comes with a dimmer. The Chinese stuff seems to be big on remotes. The US stuff often uses a 10 volt DC control, either from an active voltage source or a passive resistor on the 10 volt line from the controller. The whole thing of dimming seems to me like a big mess unless you stick with one manufacturer for all components. I'm working on my own.

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Rick C
Reply to
rickman

Or use a switchbank & a couple of capacitors. Then you can select several light levels.

NT

Reply to
tabbypurr

** Have ANY credible evidence that the idea will work?

Or are you PUI as usual.

.... Phil

Reply to
Phil Allison

Teach it the lyrics, then it won't need to hum.

Allan

Reply to
Allan Herriman

OK, my mistake in wordings.

Yes.

But can they fit inside a regular light switch box?

Reply to
edward.ming.lee

Yes, if i have enough time, i can redo the controller. But looking for quick and dirty ways for the moment. I am sure someone can do it for $1000, but not in days.

If i redo it, i would dim it at the output of the controller, not the input.

Reply to
edward.ming.lee

Just need to have different sounds. Mozart would be great. But still need a way to shut off Mozart or Beethoven, no matter how good they are.

Reply to
edward.ming.lee

Why might it not work?

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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John Larkin

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