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Re: First post: Fluorescent lighting
On 10/16/96 23:05:53 you wrote:
>
>>From ed-at-alumni.caltech.eduWed Oct 16 22:39:57 1996
>Date: Wed, 16 Oct 1996 16:45:45 -0700 (PDT)
>From: "Edward V. Phillips" <ed-at-alumni.caltech.edu>
>To: tesla-at-pupman-dot-com
>Subject: Re: First post: Fluorescent lighting
>
>Re: RFI
> Current "solid-state ballasted" fluorescent lamps sure
>produce prodigious amounts of RF interference, as to the various
>remote-control switches available for homes, and also SCR/TRIAC
>light dimmers. Where I live such interference is already so bad
>that I can, with a simple loop antenna and oscilloscope, direction
>find on many local interference sources.
> One of the "solid-state ballasted" fluorescent lamps I
>bought and tested ran at a fundamental frequency of about 39 to
>40 kHz, but I can detect harmonics of it up through 54 MHz, and
>it even interferes a bit with our TV, even though it is in a
>separate building about 100 feet from the house.
> In my opinion any of these devices is an invention of
>the devil, destined to increase RF pollution ad infinitum. As
>they become more common radio listening (for all except very
>powerful stations) will become more and more plagued with
>interference. As far as I can see, no one is seriously interested
>in regulating these things and the FCC hasn't the intent or
>resources to do anything. How do you crack down on 10,000,000 +
>noise jammers spread through as many homes, and owned by people
>who haven't the faintest comprehension of the physics involved??
>There have been proposed RF-excited lamps which are supposed to
>operate on the "interference-permitted" frequencies of 13.355 MHz
>and 27.1 MHz. I talked to an engineer involved in such a project
>and he told me his company had no intention whatever of controlling
>either the operating frequency or the level of interference
>generated.
>This is a tirade, based on years of frustration with the proliferation
>of devices such as those under discussion.
>Ed Phillips
>
>
The method I described in my first post produces little RFI because the
waveform at the load (fluorescent lamp) is purely sinusoidal. This is due,
I believe, to the high self-capacitance of the transformer. Also, there is
little current involved. Indeed solid state ballasts are noisy like
conventional ballast driven lamps. Comparing my method with other types of
systems, using a scope and loop of wire as you described, revealed no
harmonics and little em radiation.
Phil Gantt