On Tue, 07 Jun 2005 23:46:11 GMT, (JM)
wrote:

I've bought this GE/Jasco 55w 2D fluorescent fixture. The fixture is not as
advertised because the package states "five 60w bulbs" is incorrect. The
dome is too thickly frosted to achieve that claimed light output. Whoever
designed this fixture must have went by the raw lumen output of the
fluorescent tube, and probably never tested the actual fixture with the dome
in place. I've contacted GE, but they say "contact Jasco". So I contact
Jasco. Either the person responding to my email doesn't understand this, or
they don't care. In short, Jasco says: "We can't make the bulb brighter, so
just bring it back." ???? So of course I try to explain it to them again,
not the BULB but the DOME is the problem. Either make the dome less thickly
frosted, and/or at least fix the wattage claim on the box. I like the
fixture, except the lower than claimed output is a little disappointing.

Not only can't Jasco make the lamp (what you call the bulb) brighter,
but they are not going to make a new dome just for you. If you don't
like the fixture your only option is to bring it back.

Now, let's take a look at the fixture manufacturers claims.

The GE 55-watt 2D lamp is rated at 4000 lumens after 100 hours
(Initial Lumens) and 3400 Mean Lumens (that is after 40% of rated
life.)

The light output of 120-volt 60-watt incandescent lamps vary with
design life, type of diffusing coating, and a few other factors . I
would say that the GE Model 60A, which is a 120-volt, 60-watt,
1000-hour, A-19 lamp with conventional diffusing coating (not Soft
White) is a good example of a "standard" incandescent lamp. This lamp
is rated by GE for 856 initial lumens.

So, based on initial bare lamp lumens only, the 55-watt 2D would be
equivalent to 4.62 of these 60-watt incandescent lamps. However, based
on mean lumens, the 55-watt 2D is equivalent to only 3.93 of these
60-watt incandescent lamps. (Your evaluation took place with a new
55-watt 2D lamp, so the mean lumen issue is not relevant to your
problem.)

But as you have stated, bare lamp lumens are not the whole story. The
fixture must be designed to get the light produced from the lamps out
of the fixture and on to the work surface. This involves not only the
diffuser (dome) but also the reflector. I agree with your conclusion
that the manufacturer's claim is based on the light produced by the
55-watt 2D lamp, with a bit of exaggeration thrown in, and not the
light out of the fixture.

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