buzzing breakers

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recently installed 4 1500 watt lutron dimmers next to a 120 208 panel. the 4 lighting legs originally terminated at the breakers and they used to be operated by a contactor board located on the opposite wall. the contactor board is shut down ( breaker is off) because the owner just wanted to dim the dining area lights manually from the electrical room.

problem is, the breakers that are now feeding the dimmer switches are buzzing at half tilt and even more as the lights get dimmer. never been any previous buzzing prior to dimmers or when lights are at full brightness. only when dimming

is this perhaps a neutral issue? between phases? or just a compatability issue with the breaker and dimmer type.

also the wattage is well within the 80% range of the dimmers
 

fmtjfw

Senior Member
The current waveform from the dimmers might be radically different from a sine wave. It can contain higher frequency components that are causing the buzzing. Does the sound change from 0% to 100%?
 
Doesn't really "change". Just gets more intense of a stressed sound.. like a ballast how they buzz a little , but much more noticeable.

All bulbs are incandescent

Dimmers for incandescent.
 

kwired

Electron manager
Location
NE Nebraska
Dimmers are solid state devices and are modifying the current waveform. The closer you are to full brightness the closer the current waveform is to what it looks like with no dimmer at all. Is that enough to get you thinking in the right direction? I would have to do some more reasearch myself to give you a more technical answer. If you put a resistor in series with the lamps you would still have a perfect waveform but the resistor would consume a lot of energy itself as compared to the solid state devices that are used in the dimmer.
 
My main concern is damaging the breakers or the panel itself. After a while, will the breakers be defective? Also , yes, I'm thinking of doing the series with the resistor. I've never installed this type if thing. Will it fit in the 4sq, deep box along with the dimmer?
Thanks so much for sharing your experience and knowledge guys. Very assuring.

Any other fix all end all solutions need apply!

What size resistors would I need. Same as dimmers? 1500 watt?
 

kwired

Electron manager
Location
NE Nebraska
My main concern is damaging the breakers or the panel itself. After a while, will the breakers be defective? Also , yes, I'm thinking of doing the series with the resistor. I've never installed this type if thing. Will it fit in the 4sq, deep box along with the dimmer?
Thanks so much for sharing your experience and knowledge guys. Very assuring.

Any other fix all end all solutions need apply!

What size resistors would I need. Same as dimmers? 1500 watt?
The resistor in that case is the dimmer, but it needs much more space and wastes a lot more energy than the solid state dimmer you now have. It would also need to be a variable resistor to be able to vary the dimming level of the lights.

All I was saying is this is a side effect of using a solid state device for the purpose is a distorted current waveform. For the most part it will not harm anything.
 

ELA

Senior Member
Occupation
Electrical Test Engineer
They make choke coils that are designed to "smooth out" the current waveform that has been made "abrupt" by the addition of dimmers.
Adding such a coil may help this situation. The coil helps remove some of the higher frequency components introduced by the dimmer.

http://www.prolighting.com/dimmingfaqs.html
 
Ok, havnt tried this yet, but lutron says its the cheaper incandescent bulbs. They said halogen or Phillips natural light will reduce breaker buzzing dramatically or eliminate it.

Also, he mentioned a choke coil (filter) which run about $150 in which I would need 4.

Thanks for the pointers ! I'll follow up with my results!
 
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