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fartness
computersoc dot com
Premium
join:2003-03-25
Look Outside

Electrical issue

In my computer room, which has the newest wiring in the house (all three prong, grounded, etc. put in probably 3 years ago), I'm having some lighting issues.

There is a dimmer switch for the ceiling fan, and there's two outlets next to the dimmer switch. I have two battery backups for my computer plugged in there.

If I use regular old school light bulbs, they die after 3 months. I even went to Home Depot and bought the heavy duty garage vibration resistant light bulbs and they met the same fate. CFLs meet the same fate too, but I know I'm not supposed to use them on a dimmer.

Any reasons why lights just are not living long? I also notice a buzzing noise coming from the lights if I use CFL's. I even hear buzzing from my computer power supply. If I put the dimmer switch 15% of the way down, the buzzing stops. No buzzing noise from either location if I use regular old school light bulbs.

Can this buzzing noise cause harm to my computer?

I might have someone replace the dimmer switch with a regular switch since I really have no use for a dimmer. Not sure if this will help, but at least it will let me use CFLs, since I was told to not use them on a dimmer (not sure why).


John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp
kudos:8
How old are the UPSs, and the computer?


fartness
computersoc dot com
Premium
join:2003-03-25
Look Outside
UPSs are about 5 years old but still hold battery charge pretty well. Computer is 4 years old.


nunya
LXI 483
Premium,MVM
join:2000-12-23
O Fallon, MO
kudos:12
Reviews:
·Charter
·voip.ms
reply to fartness

I might have someone replace the dimmer switch with a regular switch since I really have no use for a dimmer. Not sure if this will help, but at least it will let me use CFLs, since I was told to not use them on a dimmer (not sure why).


That's your best solution. Dimmers are noisy (electrically). BTW, the wrong CFLs on a dimmer can cause a fire.

»www.youtube.com/watch?v=Ad7vhHfjgC0


Never put standard CFL's on a dimmer.
--
If someone refers to herself / himself as a "guru", they probably aren't.


fartness
computersoc dot com
Premium
join:2003-03-25
Look Outside
reply to fartness
Separate topic, can CFL's be used in the old push button switches that have one button on top for off and one below it for on (or vice versa), and then two to the side for the lighting at the other end of the hallway or wrap around stairs. I think it's probably original from 1924 when the house was built.

See my pic that I drew of an example of what it is. There's one at the bottom of my steps and one at the top. One time I turned the light on and the CFL blew up, which is why I ask this.

PrntRhd
Premium
join:2004-11-03
Fairfield, CA
reply to fartness
If you insist on using the dimmer, halogen bulbs are more able to resist the vibration created by the dimmer.


nunya
LXI 483
Premium,MVM
join:2000-12-23
O Fallon, MO
kudos:12
reply to fartness
Nope. Mashbutton switches are about as simple as it gets. From a bygone era when they built stuff to last.
Probably just a defective CFL.
--
If someone refers to herself / himself as a "guru", they probably aren't.


cdru
Go Colts
Premium,MVM
join:2003-05-14
Fort Wayne, IN
kudos:7
reply to fartness
said by fartness:

I might have someone replace the dimmer switch with a regular switch since I really have no use for a dimmer. Not sure if this will help, but at least it will let me use CFLs, since I was told to not use them on a dimmer (not sure why).

Most dimmers operate with use of a triac. A triac acts as a type of switch that rapidly turns on and off the power to lower the effective voltage at the lamp. Incandescent lamps don't mind this much as they are just a pure resistive load. Lower voltages means they don't glow as bright.

With simple CFLs, a spike in power is required to get the arc started that starts the bulb glowing. When the power is turned on and off each hertz, it's very hard on the circuitry if the bulb can even fire.

With simple LED bulbs, the AC current charges a capacitor during the peaks of the waveform so that the LED can draw the current off at a constant rate when the waveform is near 0 volts. However when the waveform is cycled on and off very rapidly, the capacitor can't charge resulting in power that isn't constant to drive the LED.

There are dimmers that are compatible (to varying degrees) with dimmable CFLs and LED bulbs. All 3 take into account how the dimming is accomplished to try to work around the limitations. However the end result isn't always as good as it looks on paper.


cowboyro
Premium
join:2000-10-11
Shelton, CT
said by cdru:

With simple CFLs, a spike in power is required to get the arc started that starts the bulb glowing. When the power is turned on and off each hertz, it's very hard on the circuitry if the bulb can even fire.

The CFL circuitry is powered by DC internally. There is a rectifier bridge inside. And anyway the AC turns on and off each period.. TWICE.
LED lights are about the same, the difference is in the voltage supplied by the circuitry to the lighting element and the fact that a CFL has an extra igniter circuit to start the light when it first gets power.
The issue with non-dimmable CFLs is that there is first a AC-DC conversion and then a DC-AC for the bulb. By feeding lower peak AC voltage you start with a lower DC voltage, which means a higher current is needed for producing the same power. This higher current may very well exceed the maximum ratings of the components, which are no doubt the cheapest that will work under the normal design conditions.


cdru
Go Colts
Premium,MVM
join:2003-05-14
Fort Wayne, IN
kudos:7
said by cowboyro:

And anyway the AC turns on and off each period.. TWICE.

Yes, but those two "off" periods are instantaneous points and aren't directly adjacent to each other. Once the triac gets involved the period of being "off" is significantly longer even when it's just dimmed a small amount, let alone considerably.

The issue with non-dimmable CFLs is that there is first a AC-DC conversion and then a DC-AC for the bulb. By feeding lower peak AC voltage you start with a lower DC voltage, which means a higher current is needed for producing the same power. This higher current may very well exceed the maximum ratings of the components, which are no doubt the cheapest that will work under the normal design conditions.

So...it's kind of like a spike in power is required to get it started and it's hard on the circuitry.


cdru
Go Colts
Premium,MVM
join:2003-05-14
Fort Wayne, IN
kudos:7

1 edit
reply to cowboyro
Deleted. Duplicate post


SparkChaser
Premium
join:2000-06-06
Downingtown, PA
kudos:4
reply to fartness


cowboyro
Premium
join:2000-10-11
Shelton, CT
reply to cdru
said by cdru:

said by cowboyro:

And anyway the AC turns on and off each period.. TWICE.

Once the triac gets involved the period of being "off" is significantly longer even when it's just dimmed a small amount, let alone considerably.

Only there is no current drawn by the bulb anyway during that time. The bulb only draws current when the AC voltage exceeds the rectified DC voltage, just to top off.
said by cdru:

So...it's kind of like a spike in power is required to get it started and it's hard on the circuitry.

A spike in power is not required to start. The internal circuit changes the frequency at startup to produce a higher voltage for the bulb, and when the bulb ignites the circuit reduces the voltage to the point of desired operation. From that moment on the bulb stays lit until the power goes away for enough time so that there are no more ionized atoms inside, being able to withstand the "off" periods of the high-frequency AC voltage it is being powered with.


Msradell
P.E.
Premium
join:2008-12-25
Louisville, KY
reply to fartness
said by fartness:

Separate topic, can CFL's be used in the old push button switches that have one button on top for off and one below it for on (or vice versa), and then two to the side for the lighting at the other end of the hallway or wrap around stairs. I think it's probably original from 1924 when the house was built.

See my pic that I drew of an example of what it is. There's one at the bottom of my steps and one at the top. One time I turned the light on and the CFL blew up, which is why I ask this.


They should work just fine.


shokeder

@telus.net
reply to fartness
Wondering if you have a bad wiring job that is causing the dimmer to be the trunk(series) of the electrical outlet circuit?

The dimmer should pigtail(parallel) off of the power line, otherwise you have it being a path(series) of power to the electrical outlet.
I have seen on occasion where people will wire light socket in a way(series instead of parallel), resulting in a downstream outlet or light having a voltage issue.

series versus parallel
»www.electrical-online.com/wiring···-series/


PSWired

join:2006-03-26
Annapolis, MD
If his outlets were wired in series with the dimmer, the UPSes would be going crazy.


fartness
computersoc dot com
Premium
join:2003-03-25
Look Outside
The UPS units do not show any ground fault indicators or any issues. They don't cycle off and on on the battery either. Only time they'll do that (for a quick second) is if I turn my laser printer on. Quite normal. I prefer UPS units over standalone surge protectors because of brownout/momentary loss of power. The battery is always there as a backup if the stream is interupted.


whizkid3
Premium,MVM
join:2002-02-21
Queens, NY
kudos:9
reply to fartness
said by fartness:

There is a dimmer switch for the ceiling fan, and there's two outlets next to the dimmer switch. I have two battery backups for my computer plugged in there.

If I use regular old school light bulbs, they die after 3 months. I even went to Home Depot and bought the heavy duty garage vibration resistant light bulbs and they met the same fate.

That's the problem with incandescent bulbs. They tend to burn out relatively quick, especially in a room where they are used often and for longer periods of time. Although you may think this is an issue, it does not sound like a problem at all. I hear this all the time from people. The bulbs are generally burning out because - surprise - they are being used. Its not the dimmer or the UPS. It never is. Ever. Try 130V bulbs if you want them to last longer. Or get rid of the dimmer and use LEDs or CFLs. Also, IMHO, a good idea to get rid of any tacky ceiling fan with the built-in bulbs and come up with a better way to light the room. (Keep the fan if you like; just get rid of the combination light-fixture.)

said by fartness:

I know I'm not supposed to use them on a dimmer. I also notice a buzzing noise coming from the lights if I use CFL's.

So why then, are you doing so? You are risking a fire. Yes, they are buzzing because you are not to run them on a dimmer.

said by fartness:

I might have someone replace the dimmer switch with a regular switch since I really have no use for a dimmer. Not sure if this will help, but at least it will let me use CFLs,

That is a really good idea. Another idea would to not use CFLs with a vibrating ceiling fan. This can only result in more costly CFLs that also burn out quickly.