On Mon, 14 Mar 2005 00:39:50 GMT, "T-M" wrote:

[snip]

Power Groove lamps are also still listed, but only
in the 8-foot size. I've seen them also used for streetlighting, area
lighting (gas stations) and billboard lighting. The grooved tube increases
the phosphor surface area compared to smooth lamps and also increases the
arc length for a given physical length. If you ever have a chance to
examine a Power Groove lamp, feel the grooves near the center. Two of them
are deeper than the others and they provide the "cold spot" that controls
the amount of mercury in the arc. Power Groove lamps became fairly widely
used in the 1960s (they appeared in 1958, I think) and were primarily
promoted for
high-bay industrial lighting.

I don't know if Gene Lemmers was the inventor. It's certainly likely. Gene
continued working at Nela Park well into his 80s and commented to me
once that he wanted to match the number of his patents to his age before
retiring.

Terry McGowan

Terry - thanks for all the good information. I thought that Gene
Lemmers was the inventor because I remember a lot of debates with Gene
and Ed Hammer in the basement of Fluorescent Engineering, 437 I think,
about why the Power Groove was more efficient than a normal 96" T17
lamp. Gene was a big proponent of the square cross section placing the
phosphor closer to the discharge, as he like to say, but there was
also the increased arc length as you point out.

--
Vic Roberts
http://www.RobertsResearchInc.com
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