UPB with CFL. Buzzing noise?

123

Senior Member
My kitchen lights are Compact Fluorescent Light (CFL) controlled by a relay-based X10 switch. The switch often fails to respond to commands, especially when the CFL lights are on (probably due to noise generated by the CFL). Before replacing the X10 switch with an SAI US1-40, I decided to set it up on a testbench and perform a few tests.

I programmed the US1-40 to be non-dimming, connected a CFL load and it appears to work fine. The light does not flash intermittently when the UPB switch is off ... a problem that appears with some X10 modules. However, I noticed the CFL bulb emits a faint buzzing noise when operating. You need to be with two feet of the bulb to hear it. It does not make this noise if connected directly to the mains or via a relay-based X10 appliance module.

I realize the US1-40 is using a triac to handle the load, as opposed to a a set of relay contacts. The buzzing may be a symptom of an adverse interaction between the triac and the CFL bulb's electronics. I don't have any evidence but I can't help but feel that it will stress the bulb's electronic ballast and shorten its life (defeating the CFL bulb's purpose).

Perhaps this buzzing noise is more pronounced with some brands of CFL than others. Has anyone else noticed it? Has it caused a reduction in the bulb's lifespan?
 
I think you nailed it. I would also say the triac even when full on maybe modifying the AC slightly.
Most CFL bulbs packages indicate not to use on a dimmer. Maybe a dimmable CFL would be better.
Even one dimmable as a test to compare to the one you are using now.
I have a few that buzz in standard fixtures; but I believe the coils in them where not wound tight enough at the Chinese factory. ;)
 
Don't know if it's related to the buzzing but take a look at the link in post 5 in this thread. It's an interesting read on dimming, triacs, cfls, etc. Personally, I will keep my incandescent/halogens until there is a decent affordable dimming LED. I'm skipping the CFL craze for many reasons.
 
Don't know if it's related to the buzzing but take a look at the link in post 5 in this thread. It's an interesting read on dimming, triacs, cfls, etc. Personally, I will keep my incandescent/halogens until there is a decent affordable dimming LED. I'm skipping the CFL craze for many reasons.

Aside from running on ACTUAL relay controlled modules, I also am only using CFLs sparsely...now, with that said, I've had this same buzzing on one of my Philips Natural Light - Bulbs. Funny thing, swap the same bulbs to other modules, sound goes away. Put different Natural Light - Bulbs into the "same" buzzing switches, no buzzing. It's strange, there must be some tolerance of specific bulbs with certain switches, as I can make the buzzing go away by just rotating the bulbs to other locations in the house.

Can you try another bulb / switch to see? I agree it's probably the Triac, but you might find a combination that works well (I did with my Natural Light).

--Dan
 
123,

I've been using CFLs (mostly FEIT dimmables now) with my UPB switches for a while. And the only time I get buzzing is when they are dimmed down to 30% or lower (ish). Mostly I've been pretty happy with them.

Perhaps a different brand of CFL? I noticed that they all behave differently with the UPB switches.

And I do have a couple of rooms setup with non-dimmable bulbs and the switches set to snap on and off with no noticeable buzzing.
 
Dan, Sam,

Thanks for your feedback. Good to know that this problem is not present with all brands of CFL's.

I don't believe I've seen the FEIT brand marketed in Canada; I'll try several others and see which ones run quietly.
 
Looked at the thread Steve mentioned. Then did a short test.

Using a Kill-A-Watt test meter. I found that two Standard CFL bulbs I have. Both drew more current when on a dimmer module at 100%, than alone. When powered by the power line.
Not a great deal more. Unless you tried to dim it. Then the current shot up 400% with an X10 Lamp Module.
 
Looked at the thread Steve mentioned. Then did a short test.

Using a Kill-A-Watt test meter. I found that two Standard CFL bulbs I have. Both drew more current when on a dimmer module at 100%, than alone. When powered by the power line.
Not a great deal more. Unless you tried to dim it. Then the current shot up 400% with an X10 Lamp Module.

BLH, which switch were you using?

I'm curious if some of that "current" increase is really due to it being an X10 switch? Do you have any US2-40 UPB switches?

--Dan
 
No strictly X10 for tests.
My home is all Insteon relay types no dimmers.
Only X10 stuff is chime modules and powerflash modules.
Part of it could have been the X10 modules.
Maybe I will get a chance to try the few Insteon dimmer modules I never installed.
 
Just as another point of info, I have a location in my house that uses 2 75W equivalent CFL from Home Depot, I believe the N-vision brand, that have the excat same buzzing but are not on any type of dimmer or automated switch. Just regular 90 cent toggle. This buzzing is particular to that location, I use CFL in other locations and with some UPB switches and do not see this. I haven't troubleshot the problem, but just wanted to let you know it can happen on non-dimmer switches.

--Jamie
 
Back
Top