What causes florecent lights to humm?

[ripsnortMN]

I installed four light fixtures in my garage this summer. Each fixture has four,four foot bulbs in each light. One of the fixtures buzzes or hums. What would cause this? Its not the radio thats for sure. It works fine but just hums. Any ideas?

 

[Mr. Jean]

Try swapping the tubes with a different one. If the problem moves, it's a bad tube. If no change, it's probably the transformer. At least thats what I was told to do years ago.

 

[kbs2244]

Sometimes the ballast isn't screwed tight to the fixture and you will get a vibration.
If swapping bulbs dosn't work you might have to open it up and check for loose screws.
Or just return it.

 

[D KRAGER]

Old style magnetic T-12 ballast will hum. You can replace with the new style T-8 electronic ballast and change the bulbs= No more hummmmm.

 

[APEowner]

They don't know the words?




Sorry, I couldn't help myself. Sometime I think my ballast isn't screwed in tight.

 

[Falcon67]

They don't know the words?




Sorry, I couldn't help myself. Sometime I think my ballast isn't screwed in tight.

 

[GeorgiaHybrid]

They don't know the words?

That's OK, my first thought was "Because they are made by Mazda?"

 

[mbatarga]

Humming can be caused by a bad ground connection.

 

[Tscott]

More specifically, the reason the ballast must be held firmly is the phenomenon of Magnetostriction.


http://en.wikipedia.org/wiki/Magnetostriction

Tom