Replies

1. 
   calvin | Apr 07, 2007 02:23pm | #1

   What kind of bulbs are you using?  Does the noise come from the cans or the dimmer?

   A great place for Information, Comraderie, and a sucker punch.

   Remodeling Contractor just outside the Glass City.

   http://www.quittintime.com/

    

2. 
   Sphere | Apr 07, 2007 02:31pm | #2

   "

   Are there any thoughts on why we are getting this humming sound?"

   They forgot the words?

   Parolee # 40835

3. 
   IronHelix | Apr 07, 2007 02:36pm | #3

   Here is my 2-cents......someone may have a better specifics on your question.

   Those can lights when "on' (dimmed or not) flow all electricity through that dimmer, which is a rheostat or variable resitance.

   As the electricity flow is squezed down to dim the lights, the dimmer will "hummmmm" louder.  Even when you have the dimmer set to full bright/on there is some resistance and with eight lights being serviced there may be a slight hum.

   You may also notice that the dimmer switch will feel warmer to the touch as you increase the amount of dimming and time duration.

   There are more than one manufacturers and more than one design for a dimmer. Some dimmers tend to humm louder than others due to quality and/or electrical configuration.

   Maybe someone will follow this up with more specific info on design and brand names. I do know that over the counter dimmers tend to be troublesome hummers more than some more expensive brand's better models...such as Lutron.

   Splitting the load on the dimmer may help or replacing it with a different style, brand, or greater wattage capacity may help you sillence the humm!

   Other wise learn to 'sing along" with the humming cans!

   Meanwhile this will bump your question up!...................Iron Helix

1. 
   BillHartmann | Apr 07, 2007 03:09pm | #4

   "Those can lights when "on' (dimmed or not) flow all electricity through that dimmer, which is a rheostat or variable resitance."No RHEOSTAT in a light dimmer.They use an electronic switch, a Triac, for standard incandensent dimmers.At each zero crossing of the AC power it turns off. The turn on is delayed depending on the setting of the dimmer. At that cause a sudden increase in voltage and thus current. With some bulbs that increase in current and cause the filaments to move and make them hum..
   .
   A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.

1. 
   IronHelix | Apr 07, 2007 03:49pm | #5

   Thanks for the correct version of the situation.

   Any suggestions for the question posted?

   ......Iron Helix

1. 
   BillHartmann | Apr 07, 2007 09:54pm | #7

   Typcially it is fixed by finding a different style/brand of bulb with different filament supports.But also "better" dimmer might help. One with a choke to help limit the current surges used to limit radio noise. But that is hard to qualify..
   .
   A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.

1. 
   IronHelix | Apr 07, 2007 10:19pm | #8

   Bill, thanks for the knowledge....you always amaze me at the knowledge depth you have of electrical stuff!

   ..........Iron Helix

2. 
   Hilltop | Apr 11, 2007 03:54am | #24

   Bill,

   Lutron also sells a set of chokes specifically for reducing hum. http://www.lutron.com/technical_info/catalogs/184-189%20Interfaces.pdf  The don't say what the inductance is;  I wonder if one installed an over rated one whether you would need to use one of their reverse phase dimmers to drive it.

   Hilltop

3. 
   BillHartmann | Apr 11, 2007 04:19am | #25

   "I wonder if one installed an over rated one whether you would need to use one of their reverse phase dimmers to drive it."I don't think so.But any phasors in a 500 ft radius that were set to Stun would be rendered useless.
   .
   .
   A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.

4. 
   Hilltop | Apr 13, 2007 02:13am | #26

   Bill,<!----><!----><!---->

   I was actually quasi-serious; the combination of the inductors physical appearance, and the tight load rating (with minimum load) lead me to believe that they are not little RF chokes, but are instead intended to create a tuned circuit.  (And presumably tuned to eliminate the audio frequencies in addition to the RF).  As such the voltage turn off spike associated with turning off the zero cross is substantial due to the potentially large phase shift.  Thus a circuit that shuts off at zero current would be more appropriate than the standard triac. But it would be easier to just follow the minimum current levels, prompting my weak effort at jesting about using the much more expensive reverse phase dimmers which Lutron also makes (but which are actually intended for a rectified capacitive load).<!----><!---->

   Best regards,<!----><!---->

   Hilltop<!----><!---->

       

5. 
   BillHartmann | Apr 13, 2007 03:17am | #27

   If I am not mistaken triac actually turn off a zero current. But it has been many many years since I looked at the electrical characteristics.Also I believe that there needs to be a minimum current level when it fires. That is why special dimmers are recomended for magnetic loads.Have really not followed what is used for the switches in dimmers for magnetic or switching power supplies. But I had never heard them called "reverse phase"..
   .
   A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.

6. 
   Hilltop | Apr 13, 2007 03:57am | #28

   Bill,<!----><!----><!---->

   They do turn off when the triac drops below it’s holding threshold, but that level can be hundreds of milliamps with a dV/dt of 500 or 1000V/uS. (Though the more expensive sensitive gate devices can be much lower).<!----><!---->

   The larger lighting manufacturers make dimmers intended for low voltage transformers; they advertise that they are intended to remove the problems associated with potential DC bias (and thus transformer saturation), but I bet they also include a snubber to take care of the spike.<!----><!---->

   They also have zero voltage turn on devices (which Lutron refers to as a reverse phase dimmer), to prevent the big current spike that would otherwise result from turning on at maximum voltage.  It’s amazing how much fuses and circuit breakers have to be oversized from nominal levels unless one adds an input current limiter.  The newer power factor corrected supplies are much better in this respect, as a lot of them seem to have  built in the current limiting.<!----><!---->

    <!----><!---->

   Lutron also has some neat designs where they have a relay parallel to the triac to give a soft turn on from the triac, and then eliminate the losses from the triac (though this clearly does not work for a dimmer application).<!----><!---->

   Here is the link to Lutron’s general description of dimmer types: http://www.lutron.com/technical_info/catalogs/198-199%20Dimming%20Basics.pdf<!----><!---->

    <!----><!---->

   They do not give any circuit descriptions or schematics at their web site, but I have found some of them at the US patent office.<!----><!---->

   Best regards,<!----><!---->

   Hilltop<!----><!---->

    <!----><!---->

    

2. 
   BillBrennen | Apr 07, 2007 10:45pm | #9

   What Bill H. said is right on. My experience is that trying different brand lamps gives better results than switching out the dimmers. 65 watt Phillips R30 lamps are pretty quiet. In general, the more expensive lamps seem to have better filament support, and are thus less noisy on a dimmer.Bill

2. 
   SoccerMomX3 | Apr 07, 2007 11:19pm | #10

   Thank you for your input. We are using a Leviton dimmer that I got at Home Depot. I will look for a Lutron and see if that helps.

1. 
   maddog3 | Apr 08, 2007 05:19am | #12

   no dimmer will mask the buzz from cheap lamps..work backwards toward the dimmer.
   130V lamps as were mentioned might fix the problemif there is a supply house nearby ask for"contractor grade" if "130Volt lamps" gets you puzzled looks...

   .

   .

   ., wer ist jetzt der Idiot ?

1. 
   SoccerMomX3 | Apr 08, 2007 06:03am | #13

   We just replaced them with Phillips 65W bulbs and the humming went away in one room with 5 can lights but in the other room (with 8 can lights and a fan w/4-60W bulbs) the buzzing is now in the dimmer. Any thoughts on that one? Should I upgrade bulbs or dimmer?

1. 
   maddog3 | Apr 08, 2007 06:09am | #14

   you have a fan on the same dimmer?
   .

   .

   .

   ., wer ist jetzt der Idiot ?

2. 
   SoccerMomX3 | Apr 09, 2007 06:16am | #15

   Actually, the fan operates on a remote but is tied into the switch for the can lights. We can have the can lights on but the fan and fan lights do not have to be on. Do you think that this is a problem?

3. 
   maddog3 | Apr 09, 2007 01:08pm | #17

   only if the switch HAS to be on for the fan to run..
   .

   .

   .

   ., wer ist jetzt der Idiot ?

4. 
   SoccerMomX3 | Apr 09, 2007 08:58pm | #18

   Yes, the switch has to be on for the fan to run...I guess we need to run a separate wire and switch for the fan and lights.

5. 
   maddog3 | Apr 10, 2007 11:57am | #20

   yes, the fan should not be on a dimmer !you will have some hum when you use dimmers or fan speed controls... regardless .
   .

   .

   .

   ., wer ist jetzt der Idiot ?

6. 
   SoccerMomX3 | Apr 10, 2007 07:54pm | #21

   Thank you for your input....We'll look into having another line pulled for the fan.

7. 
   CapnMac | Apr 10, 2007 08:05pm | #22

   We'll look into having another line pulled for the fan.

   Any chance of a phone-camera shot of the switch with the cover off?

   You said "remote" before, for the fan.  That can be a hassle for some switch installs; but, if it's a "three wire" (white, black, and red), then it's possible, maybe, to power the remote's switch unit for the fan from the w/b pair; then use the red for the dimmer to the lights.  Maybe.  (Did I use enough qualifiers?<g>)Occupational hazard of my occupation not being around (sorry Bubba)

8. 
   maddog3 | Apr 11, 2007 02:47am | #23

   anytime, keeps us posted.

   .

   .

   ., wer ist jetzt der Idiot ?

9. 
   BillBrennen | Apr 09, 2007 09:11am | #16

   The load you describe is 760 Watts, plus the fan. Unless you have a 1000 Watt dimmer, it is overloaded (>600 Watts).The fan should not be fed through the dimmer, but separate from it. If you want variable speed, you need a special controller, and it may also depend on the specific fan. Ask the manufacturer/read the full paperwork that comes with the fan before proceeding.BillEdit: You have a 1000 Watt dimmer which should handle the lighting you describe. The fan might be the culprit, or a bad dimmer. Try taking the fan out of the loop and see if the buzzing goes away. It should not be on the dimmer anyhow. -Bill

   Edited 4/9/2007 2:15 am by BillBrennen

10. 
    SoccerMomX3 | Apr 09, 2007 09:00pm | #19

    We do have a 1000 dimmer and the fan/fan lights are on the same switch. I guess we need to run a separate wire for the fan and its lights. Thank you for your input.

4. 
   thebozer | Apr 07, 2007 03:54pm | #6

   use a 130v bulb.

5. 
   seb | Apr 08, 2007 02:13am | #11

   Before you go changing stuff you need to find exactly where the "humming" is coming from. Then act accordingly
   Bud