Larger than normal buzzing from 3 way dimmer among other

[aelectricalman]

There were only 7 recessed lights on this dimmer, so the Amperage should have been ok to support a dimmer switch. What other factors could have contributed to this issue? I tried 2 seperate types of dimmers. The first would not dim the lights but turned them on and off correctly according to the properties of the 3-way. The second dimmer hummed really loud until the dimmer was fully turned on. Is there something i am missing?

 

[ghelec]

Re: Larger than normal buzzing from 3 way dimmer among other

Check your actual amperage with a meter to be sure. Never ran into this situation,this would be a place to start.

 

[aelectricalman]

Re: Larger than normal buzzing from 3 way dimmer among other

Less than 4 Amps. 60watt bulbs.

 

[divo2500]

Re: Larger than normal buzzing from 3 way dimmer among other

whats buzzing....the lamps or the dimmer? I just finished a house with 70 recessed cans and 17 lutron dimmers. When all turned on and dimmed down the lamps were buzzing so loud you could hear it from the basement. I called lutron and they told me to replace the lamps with heavy duty bulbs with larger filiments. They gave me the make/model for the lamps. Dont have it with me now but it wasnt cheap. I replaced them and now its louder...lol. I called them back and now waiting for a reply.

 

[aelectricalman]

Re: Larger than normal buzzing from 3 way dimmer among other

Its the Dimmer and its a Lutron. LOL. I do not understand why its so loud, a mean its is annoying from 25ft away on the couch.

 

[aelectricalman]

Re: Larger than normal buzzing from 3 way dimmer among other

I'll try this again when I learn English.

It is the dimmer and it is a Lutron. LOL. I do not understand why it is so loud for it is annoying from 25ft away. I noticed the buzzing while sitting on the couch. There; better.

 

[charlie b]

Re: Larger than normal buzzing from 3 way dimmer among other

If you had used two of the same make and model of dimmer (which you did not), and if they both showed the same symptom (which they did not), this might have indicated a problem within the wiring system (i.e., the wires themselves, or one of the luminaires). However, you said you used two different types of dimmers, and the two had different types of problems. I would suggest replacing the second dimmer with another one of the same make and model, and see if anything changes.

 

[rattus]

Re: Larger than normal buzzing from 3 way dimmer among other

Speaking of noisy things, it is often enough to make sure that the device is not free to move excessively. This is often the case with small fans in heaters and exhaust fans. Be sure everything is snugged down properly.

Another question: Are the dimmers noisy on full brightness?

 

[physis]

Re: Larger than normal buzzing from 3 way dimmer among other

I'm guessing if you replace that dimmer this might, not go away, but behave like dimmers usually do.

I might be wrong about this.

Doesn't the dimmer cause the sine wave to be cut and then drop immediately to zero? Sure there's a tiny capacitor to clean that up but I wouldn't expect there to be even a watt in it.

I think these things are inherently noisy because they're chopping up the wave.

Edit: No, I think I'm backwards, it's two SCR's. It switches on immediately. That means not even a capacitor to help.

[ January 07, 2005, 07:00 PM: Message edited by: physis ]

 

[rattus]

Re: Larger than normal buzzing from 3 way dimmer among other

Light dimmers use something called a "Triac", a five layer piece of silicon which conducts in either direction when triggered. This is cheaper than using 2 SCRs. They chop of the front part of the positive and negative lobes of the sine wave to cut the power.

The better dimmers have an RF filter which is a ferrite core wound with a few turns of magnet wire and perhaps a cap. I would suspect that this inductor might hum with a heavy load--especially if it is in a steel box.

Some of my lamps buzz, but I near no noise from the dimmer itself.

 

[physis]

Re: Larger than normal buzzing from 3 way dimmer among other

I love this place!

Edit: and because the SCR stays on until the current across whichever layers (anode and cathode?) stops.

[ January 07, 2005, 07:44 PM: Message edited by: physis ]

 

[rattus]

Re: Larger than normal buzzing from 3 way dimmer among other

The 3-way dimmers I have seen have to be wired exactly so or they won't work right--maybe they might buzz. But all you pros already knew that didn't you? I had to remove a pair because they didn't have an RF filter and that glommed my modem. Leviton.

 

[msd]

Re: Larger than normal buzzing from 3 way dimmer among other

You are not trying to dim low voltage lighting with a standard incandescent dimmer are you?

 

[aelectricalman]

Re: Larger than normal buzzing from 3 way dimmer among other

The original post states that I am trying to dim recessed cans. Also, I did try 2 dimmers of each type both did the same thing. The first try (tried two different ones) yeilded a switch that buzzed loud. The second try (tried a different type of switch again- two different ones). This type of dimmer would not dim, but worked otherwise. What I am getting at with this post is that it was not the dimmer. It is something mechanical. I went back and checked my connections. There is a range wire which is fairly close to a number of the cans (4), but it even does the humming gig when there is not amperage in the range line.

 

[aelectricalman]

Re: Larger than normal buzzing from 3 way dimmer among other

Original Post:

There were only 7 recessed lights on this dimmer, so the Amperage should have been ok to support a dimmer switch. What other factors could have contributed to this issue? I tried 2 seperate types of dimmers. The first would not dim the lights but turned them on and off correctly according to the properties of the 3-way. The second dimmer hummed really loud until the dimmer was fully turned on. Is there something i am missing?

Thank you.

 

[physis]

Re: Larger than normal buzzing from 3 way dimmer among other

a switch that buzzed loud

Well, that's interesting. No triacs in those.

 

[harvey828]

Re: Larger than normal buzzing from 3 way dimmer among other

aelectricalman,

Just grasping for straws here, but you might try checking the circuit for the presence of the 3rd harmonic. The easiest way to do this is to check for a 180 Hz signal on the branch circuit. Lots of times this can be fixed by simply rearranging some of the load in the panel.

 

[bensonelectric]

Re: Larger than normal buzzing from 3 way dimmer among other

I have never had this sort of experience with Lutron dimmers, they usually buzz, not very loudly though... I have even overloaded them, put a 750-watt elipsodial fixture on a 600-watt dimmer, and on low (when most power is being consumed by the SCR's and converted to heat) only a minor buzzing was present... I could understand a loud buzzing if this was an older dimmer, but recently the noise has been decreased significantly...

 

[rattus]

Re: Larger than normal buzzing from 3 way dimmer among other

Matt,

I believe the triac is in series with the load, therefore full brightness would create the most heat in the triac.

 

[physis]

Re: Larger than normal buzzing from 3 way dimmer among other

I was thinking that too Rattus.

It's just an open circuit until the triac is triggered. No dissipation in off state.