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Re: Buzzy fluorescent fixtures

>Date: Tue, 6 May 1997 07:29:02 -0400 (EDT)
>From: Earle Hamilton <ehami at sunny_ncmc.cc.mi.us>
>I have been bothered by an occasional noisy light.  In one case I noticed 
>the fixture was exactly like four others that I had.  All were magnetic 
>"ballasts" and BTW all are about 30 years old.  They were in storage for 
>20 years.  At any rate, I tried to determine the problem.  First I put in 
>a new bulb which made a big difference.  However, it was still too noisy, 
>especially compared to the three "good" fixtures.  While I am not exactly 
>sure what the problem is, I suspect the little plates that make up the 
>core of the ballast become "loose" which gives the opportunity for the 
>light to double as a door buzzer.  The amplitude of the noise, I'm 
>guessing, is a function of the load on the transformer (ballast).  

From what I remember of my college Physics II class, a noisy transformer is
a transformer under load whose packing is no longer holding the iron loop
or bar still with reference to the input and output coils.  The buzzing and
shaking are due to the physical movement of the coils on the iron.

They mentioned that as a transformer ages, it tends to start buzzing.

David W. Webb           Corporate Business Systems
Texas Instruments Inc.  Dallas, TX USA
(972) 575-3443 (voice)  dwebb at ti_com
(972) 575-4853 (fax)    http://www.dallas.net/~dwebb
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