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[OM] OT lamp data (delete at will)

Subject: [OM] OT lamp data (delete at will)
From: Acer Victoria <siddim01@xxxxxxxxxxxxxxx>
Date: Tue, 22 Jun 1999 16:00:31 -0700 (PDT)
OT; not too long, so bear with me. Else skip to my note on bottom :-)
/AV

Excerpts from: <http://users.deltanet.com/~jlagerqu/slidefaq.txt> Go there
to read more than you ever want to read. This was the only site with
useful info I found.

>>>>>>>>
Delbert's advice and caution is absolute correct. Utilize the
features that the manufacturers built in to their projectors for
dimming and control. Don't bypass them. And another point: most
slide projector manufacturers recommend that you do NOT leave the
fan running after you have shut the lamp off. This artificially
cools the lamp down faster than it would naturally, and actually
reduces lamp life. However, it is essential that the fan be
running while the lamp is in use, and receiving full power at all
times-reduction via dimming can certainly burn out the fan motor.
<<<<<<<<<

>>>>>>>>>>>
Mike Peters writes "The problem with dimming slide projectors
with the cd80  dimmers is that the fan will also go out with the
lamp shortening the lamp  life."

I believe that this is incorrect.  In fact, turning the fan off
with the  lamp will lengthen lamp life.  Leaving the fan running
will over cool the  lamp and it is the change from cold to hot
that puts most of the wear in a  lamp. Don't you generally warm
lights slowly to prevent burnouts, when you  first turn them on
each day?  I do.  The fan is meant to cool the lamp while  it is
running.  When you turn the lamp off, you should turn off the fan
at  the same time, unless you need to move the projector right
away.  Then,  simply let the fan run briefly to cool the lamp to
just warm, so filiments  won't break when being moved.
<<<<<<<<<<

>>>>>>>>>>>>>>>>>>>>>>>
Actually to clarify I believe that shutting off the fan on the
projectors  will not cause much problems with the lamp but rather
the slides.  Isn't  the primary purpose of the fan to prevent the
slide from turning into a  fireball.  I believe that the lamp
does not cool off fast enough after it  is turned off and the fan
keeps the slide cool until the temperature  inside the projector
has cooled to a safe temperature.  It has been a  while since we
worked on our projectors but I believe the lamps are wired 
directly.  We usually run them from the booth and just push the
regular  advance buttons to change the slides.  Since we are in
the booth we  usually do turn off the fan after a couple of
minutes.
<<<<<<<<<<

>>>>>>>>>>>>>>.
But as to out of the box Ektas a call to Kodak themselves will
verify  their strong view that the fan should go off with the
lamp. The problem  is primarily with the heat filters but
includes other g;ass parts as  well. You see heat filters work by
turning the heat energy into  mechanical energy. They are thus
quite prone to instant shattering, easy  breakage, and even small
explosions. The blast of cold air from a fan  when the heat
source turns off provides a severe shock to this system  which
would much rather be cooled down slowly.
<<<<<<<<<<<

my observation:
>>>>>>
some projectors have timedelayed fan shutoff
<<<<<<<<

I am formally withdrawing from said debate in favor of spending time
shooting for ADITL. Apologies to all toes tread on, time and bandwidth
wasted.

/Acer "cheeky whippersnapper" Victoria
--
"Like a cat / Dragged in from the rain / Who goes straight back out / To
do it all over again / I'll be back for more / ...."    --Depeche Mode
http://student.ucr.edu/~siddim01/       <--don't visit just yet!








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