Humming Dimmers

Users who are viewing this thread

ScottTENN

New Member
Messages
19
Reaction score
0
Points
0
I got 3 dimmers from HD in the $10-15 range. (Really all they had in a 3way dimmer.)

Two of them have been installed and they, not the lights, produce a slight hum as the lights are dimmed. The dimmer the more hum. If there was background noise in the room, tv or radio you would probably never notice it. Normal?

Also while turning one off, since i dont have cover plates on yet, I could feel heat from the housing. They are not dimmed while I'm working in the room. Are they supposed to get warm, noticably warm?
 

Jimbo

Plumber
Messages
8,918
Reaction score
18
Points
0
Location
San Diego, CA
Cheap dimmers ( under $40) could be susceptible to hum, and to getting warm. Are you dimming fluorescent bulbs?
 

TheElectricalGuru

National Electrical Code Expert/Speaker/Educator
Messages
10
Reaction score
0
Points
0
Website
www.TheElectricalGuru.com
I could not resist......what song are they exactly humming?

Anyway.....check the dimmers, verify the wattage allowance of the dimmers and if they are designed for the application you are using them for. ( ie: floures and so on )
 

ScottTENN

New Member
Messages
19
Reaction score
0
Points
0
They are for incondecent bulbs, 600w. The most I have is 360w, 6x60w.
I have read about the bulbs humming, but this is the dimmer. I guess they are still to cheap. They say that have an RFI filter, but it must be filtering something else.

My worry is really the heat.
 

Jadnashua

Retired Defense Industry Engineer xxx
Messages
32,770
Reaction score
1,190
Points
113
Location
New England
While on, few dimmers pass all of the voltage to the bulbs attached - they act sort of like a like a small resister - almost like the filament in the bulb...they'll get warm. Well, not exactly true, but it works as an example (the details are more complicated than that depending on the exact type). Shouldn't get really hot, but maybe warmer than you're used to. Some rheostat type dimmers have a bypass switch to connect the line directly, so when full on, they normally don't get hot, but all of the other types do to some degree or another. You'll notice on many that there are aluminum tabs on the sides. These are heat sinks - small radiators to dissipate heat. The instructions say if you remove them (you might have to to get them to fit a multi-gang box), you need to derate the dimmer so it won't handle as much current.

When the switch is on, if you took a multimeter and measured from the hot in across the dimmer to the output to the light, you'll measure a little voltage. The higher the voltage (across the switch when it is full bright is an idea of how good the electronics are inside of the switch...the higher the voltage, the hotter the switch will become. Note, this only is valid when it is full bright, it should increase as you dim the lights.
 
Last edited:

Jar546

In the Trades
Messages
424
Reaction score
0
Points
0
Location
USA
Website
www.inspectpa.com
You get what you pay for. You paid crap, you got crap and now you have a problem. Go to a real electrical supply house and tell them what you need and what problem you are having. Take some cash.
 

Geniescience

Homeowner
Messages
2,137
Reaction score
4
Points
0
Location
humid summers hot, humid winters cold
I've had humming dimmers too, and I didn't like it. They also got hot.

I've asked around a lot about it. I've been told stories about rheostats and silicon controlled rectifiers and more. It basically comes down to this: Home Depot sold you 20th century technology, not current (21st century) technology.

I have often taken merchandise back to HD much later than just weeks or months after purchase. They have always taken it back without much of a struggle. I get a little card and buy more stuff before leaving. Stuff I know I will keep.

David
 

Bill Arden

Computer Programmer
Messages
584
Reaction score
0
Points
0
Location
MN, USA
Website
www.billarden.com
The problem is that there are very few choices in that small of a package.

Methods of dimming a light.

1. Cheep SCR based dimmer. This type switches at 120 Hz

2. Cycle dropping SCR dimmer. This type changes the pattern of on-off to better drive motors. (I designed one of these for a company project 10 years ago)

3. Dual FET based dimmer. This type can switch at higher frequency's and can drive motors.

4. "true sine wave" switching supply. The size of this type of circuit is getting smaller every year and someday could fit inside of a switch package.

5. Variac. These are large and heavy.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks