Author Topic: Incandescent buzzing on a dimmer  (Read 1961 times)
Attfreakk
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Incandescent buzzing on a dimmer « on: December 14, 2020, 11:36:47 PM » Author: Attfreakk
Why do high wattage incandescents buzz so loudly when on a dimmer? It is driving me CRAZY!
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Medved
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Re: Incandescent buzzing on a dimmer « Reply #1 on: December 15, 2020, 01:59:50 AM » Author: Medved
High currents mean large magnetic forces and that means noise.
Running tzem full power means 120 or 100Hz hum, which is too low frequency to be radiated by the lamp or lantern, but the dimmer generates sharp edges with a lot of harmonic content in the kHz range, where the assemblies radiate tze noise very readily.
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Binarix128
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Re: Incandescent buzzing on a dimmer « Reply #2 on: December 21, 2020, 11:57:14 AM » Author: Binarix128
Medved is right. It also happens to me but when there's a bad contact in the outlet and when I dim the light down the 100Hz noise is more noticeable.
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BG101
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Brian TheTellyman
Re: Incandescent buzzing on a dimmer « Reply #3 on: December 30, 2020, 09:14:07 PM » Author: BG101
I guess the "ringing" noise is more prominent with coiled-coil lamps vs. single-coil where magnetic influences are involved. I also remember this phenomenon becoming prominent even directly off the mains, when a lamp was nearing EOL.

Sometimes the "buzzing" can be heard from the dimmer itself where components resonate.
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Re: Incandescent buzzing on a dimmer « Reply #4 on: January 02, 2021, 02:38:50 AM » Author: Medved
There are two noisy components in the dimmer: Sometimes it is the filter choke, but more often it is the capacitor in the snubber (a series RC across the triac helping it with correct switching).
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Binarix128
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Re: Incandescent buzzing on a dimmer « Reply #5 on: January 02, 2021, 10:44:34 AM » Author: Binarix128
Probably there is a piezoelectric effect in the PCB or the silicon of the triac, and it becomes more noticeable at high loads, it can also be a bad contact in the bulb socket, the dimmer connections or the outlet that is arching or it's a highly resistive spot.
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xmaslightguy
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Re: Incandescent buzzing on a dimmer « Reply #6 on: January 02, 2021, 07:14:14 PM » Author: xmaslightguy
I've noticed that some incandescent lamps do make a slight buzzing sound when dimmed.

I've also noticed if you dim a large load of incandescent Christmas lights, it'll make some devices around the house (and/or the breakerbox itself) hum/buzz quietly. I'm guessing because it probably creates 'noise' on the lines..
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Re: Incandescent buzzing on a dimmer « Reply #7 on: January 02, 2021, 07:21:29 PM » Author: joseph_125
I've noticed the same too. Generally with the incandescent lamps that use unsupported vertical filaments. The rough service incandescent lamps with the supported filaments generally buzz quieter than their general service cousins.

Dimming with a variac can cut the buzzing too, at the trade off of the higher expense of a high power variac and the fact that some variacs do hum like a ballast under load.
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Binarix128
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Re: Incandescent buzzing on a dimmer « Reply #8 on: January 02, 2021, 07:38:45 PM » Author: Binarix128
I've heard some incandescents humming under dimmer too. That's because of the fast thermal dilatation. An incandescent or a big LED blinking set will insert noise into the lines, because they consist in triacs dimming the lights, and it creates harmonics.
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takemorepills
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Re: Incandescent buzzing on a dimmer « Reply #9 on: January 03, 2021, 12:57:34 AM » Author: takemorepills
I have several R40/150watt lamps in my man cave on dimmers.
They buzz quite loudly when "cold" (and dimmed), but after a few moments they become quiet (even when dimmed).
I'm guessing it has to do with the thermal dynamics in the lamp, heavy duty filament (130V long life) high wattage and a heat reflector mounted to the stem make for a noisy bulb. Luckily, they do quiet down after a few moments, because we have 10 of them it could be annoying if they didn't quiet-down.

And my setup requires high-wattage dimmers. The lamps are on 2 separate circuits each run by a 1000watt dimmer.
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Medved
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Re: Incandescent buzzing on a dimmer « Reply #10 on: January 03, 2021, 11:35:17 PM » Author: Medved
Probably there is a piezoelectric effect in the PCB or the silicon of the triac, and it becomes more noticeable at high loads, it can also be a bad contact in the bulb socket, the dimmer connections or the outlet that is arching or it's a highly resistive spot.

If it goes with high load, the noisy culprit uses to be the filter choke.
Nor PCB, nor triac make any noise. On the PCB is no arrangement leading to piezoelectric effects (unlike within the snubber capacitor) and the triac is just plain too small (the silicon itself has few mm, plus the active triac structure itself is just few 10's um thick, the rest of the ~200..500um thick silicon is just a highly doped substrate doing electrically nothing) and there is no effect causing any mechanical movement (it would mechanically destroy the chip in the first place, if anything like that would happen)
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Re: Incandescent buzzing on a dimmer « Reply #11 on: January 04, 2021, 01:04:54 AM » Author: xmaslightguy
@takemorepills:
A fairly decent electrical load there...
Does it make any other devices around the house and/or the breakerbox itself buzz or hum when they're dimmed at various levels?
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takemorepills
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Re: Incandescent buzzing on a dimmer « Reply #12 on: January 04, 2021, 01:11:58 AM » Author: takemorepills
@takemorepills:
A fairly decent electrical load there...
Does it make any other devices around the house and/or the breakerbox itself buzz or hum when they're dimmed at various levels?

No, there's no other buzzing.
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BG101
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Brian TheTellyman
Re: Incandescent buzzing on a dimmer « Reply #13 on: January 04, 2021, 08:20:45 PM » Author: BG101
I've also noticed if you dim a large load of incandescent Christmas lights, it'll make some devices around the house (and/or the breakerbox itself) hum/buzz quietly. I'm guessing because it probably creates 'noise' on the lines..
I wonder if it's also acting as an induction loop? Sounds plausible if you have them strung out around the room.
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Re: Incandescent buzzing on a dimmer « Reply #14 on: January 04, 2021, 09:29:58 PM » Author: xmaslightguy
Quote from: BG101
I wonder if it's also acting as an induction loop? Sounds plausible if you have them strung out around the room.

Its possible it coulda set up some sorta weird induction-loop type thing?
This wasn't just one room inside, but all around the house outside! I had to split the load over a few different breakers since it would have been way over the limit for just one.
I think it affected the whole house(but was only apparent in some things)... I do know if I flashed them instead of fade on/off, that could be seen anywhere if you looked for it .LOL.
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