light humming

[mo]

Hello, I have a flouresent light fixture above my sink. When it is on it humms loudly. I have replaced the tube and it has no starter. What is causing the hum? PS it is an old fixture

[RBM]

The ballast transformer

[buffalobill]

"Magnetic ballasts modulate electrical current at a relatively low cycle rate, which can cause a noticeable flicker. Magnetic ballasts may also vibrate at a low frequency. This is the source of the audible humming sound people associate with fluorescent lamps.

Modern ballast designs use advanced electronics to more precisely regulate the current flowing through the electrical circuit. Since they use a higher cycle rate, you don't generally notice a flicker or humming noise coming from an electronic ballast. Different lamps require specialized ballasts designed to maintain the specific voltage and current levels needed for varying tube designs." more about flourescent lights at:

[maradcliff]

Like others said, its the ballast The metal core pieces are vibrating probably due to a loose housing. Some of the old ones that were held together with a metal piece that goes around 3 sides can be quieted by squeezing that metal piece. Otherwise, replace the ballast, but first price a new fixture. Many times the fixture costs less than a ballast.

[Jeff Wisnia]

If squeezing it doesen't quiet it down, try removing it, placing it on a firm surface and denting it SLIGHTLY with a ball peen hammer in a few places. Sounds drastic, but it's worked for me.

Jeff

[RicodJour]

Hmmm. You didn't mention replacing the ballast in the fixture, so this is how you "teach" the ballast some respect? Beat the crap out of it with a ballpeen hammer? You're a tough man, Jeff. ;)

R

[mm]

One could then donate the old fixture to someone who wouldn't mind the humming, like a factory or a band without a rhythm section.

Remove NOPSAM to email me. Please let me know if you have posted also.

[Tony Hwang]

Hi, You have to hit it with an experienced authority or you'll kill it good, LOL!