Incandecent Buzzing


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Old 01-30-08, 05:52 AM
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Incandecent Buzzing

I had a question regarding a couple of torchiere lamps i bought at home depot which use a three way switch for a three way bulb - 50, 100 and 150. i plugged them into outlets controlled by lutron dimmers and even when they are full-on, they buzz. When you dim them, they buzz louder.

i have several other hanging fixtures controlled by these same type of dimmers and there is no noise at all. Is this a function of the lamp wiring or maybe the type of bulbs?

i don't want to use them if i keep getting the annoying buzzing.

Thanks for any advice.
 
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Old 01-30-08, 05:58 AM
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Hmm. Receptacles are not allowed to be dimmed, so you have an issue already.

Three way bulbs, to the best of my knowledge, are not designed to be dimmed, since they are for plug in lamps, which cannot be dimmed since they have a cord and plug.

Fix your problem, install normal switches.
 
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Old 01-30-08, 05:59 AM
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First problem you have is receptacles controlled by dimmers. That is not permitted by code. You should change the dimmers back to switches.

Buzzing from dimmers is caused by the brand of bulb you are using. Switching to a different brand might help.
 
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Old 02-02-08, 06:43 AM
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i tried a regular 150 watt bulb (not 3-way) - same buzzing
 
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Old 02-02-08, 09:03 AM
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What other two guys been telling you PLEASE remove the dimmer from the repectale circuit this is not allowed on genral circuits at all.



i have several other hanging fixtures controlled by these same type of dimmers and there is no noise at all. Is this a function of the lamp wiring or maybe the type of bulbs?

is this controled by table top dimmer switch ??

tabletop dimmer photo

please tell us so we will know the answer

Merci, Marc
 
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Old 02-04-08, 04:50 AM
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not a table top dimmer switch.

this is a lutron dimmer with IR remote control just like all the rest of the ones in the house which control regular mounted fixtures.
 
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Old 02-04-08, 07:10 AM
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Originally Posted by racraft
Hmm. Receptacles are not allowed to be dimmed, so you have an issue already.
Just curious--why does the NEC disallow this?
 
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Old 02-04-08, 10:47 AM
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Originally Posted by jumpyg
Just curious--why does the NEC disallow this?
BEcause you could plug a vacuum or TV into the dimmed receptacle which would result in damage(possibly fire) to the dimmer, the TV etc. or both.
 
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Old 02-04-08, 10:56 AM
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Originally Posted by joed
BEcause you could plug a vacuum or TV into the dimmed receptacle which would result in damage(possibly fire) to the dimmer, the TV etc. or both.
Ah, yes, that makes perfect sense. Thanks.
 
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Old 02-25-08, 08:33 PM
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When you dim them, they buzz louder.

inside the dimmers are ferrite cores, this helps prevent back EMF (high frequency oscillation of magnetic fields from forming). If you still hear allot of buzzing , the triacs (voltage phase controllers) are NOT ON ALL THE WAY.

replace the dimmer, probably the series resistor in the dimmer potentiometer, is the wrong value, for your situation ... what ever their using, 1/2 the value if you want to open it up, then the full 360 degrees of the sine wave will be fully connected to the appliance / bulb, not only 280 degrees of it, you can buy ferrite rings that coil around your chord , 2" or 3" ones will usually 'help' stop allot of the high frequency back EMF (high voltage spiking in the power lines / wires).

When these triacs (in light dimmers), trigger to be on only at a certain part of the 60 cycle power signal, they switch off and on, depending on how dim you want the light. More light, More power, more degrees of the sine wave let thru, or applied (from 0 to 180 degrees of the sine wave). When it switches on or off, the time it takes is thousandths of a second on or off, in a long loop of house wiring or any coils in the circuit, the magnetic fields cause these coils or wire to 'ring' or buzz, like the old phone lines still do. This ringing is what you hear ... its oscillating.
 

Last edited by pdp8e; 02-25-08 at 08:41 PM. Reason: added info
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Old 02-26-08, 11:36 AM
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thanks for the great explanation. this really helps in understanding what is going on with the dimmers.

luckily, i tried yet another lightbulb brand and this time, the buzzing is not there. so, in my case it was a bulb issue.

i also had the buzzing in another room with a plug-in type dimmer but when i switched the bulb brand, the buzzing went away at this location as well.

thanks for all the responses.
 
 

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