🚀 go-pugleaf

IMHO, you are not being paranoid
I have an old Zeiss 200-watt ("pumpkin lamp) system, and I wish I knew how
far away was far enough.  I once fried a board in the zeiss MC100 camera
attached to my Universal when I started the lamp (the camera was turned
on, and its controller sits right next to the microscope).  On another
occasion, I took out the power supply in a Macintosh connected to a
different microscope in the room (the computer was on) and burned a short
trace on the screen of a video monitor that was a good 8 feet away (the
monitor was on).  All of this became somewhat more understandable when,
after I hooked up a stereo in the room (some 12 feet from the fluorescence
'scope), I noticed a loud "POP" from the speakers whenever I pressed the
igniter button on the lamp supply.  There are two other computers in the
room, some 25 feet from the lamp.  They have never been affected.
So I would guess that the EMP originates from the lamp and the cord, and
that having the equipment on different circuits, or having
surge-protectors on the circuits offers no protection whatsoever.  I now
make sure that *everything* within a fifteen-foot radius of the lamp is
turned off before I start the lamp.  
HTH
Julian Smith III
Biology
Winthrop University

> I have some questions concerning the prudent use of UV (e.g.
> mercury/xenon lamp) power supplies.  We are setting up a new microscope
> that is equipped with an Opti-Quip Model 1600 Power Supply powering a
> 200 watt mercury/xenon lamp.  I'm concerned about warnings I've read
> about turning off all other electrical equipment before firing up the
> lamp (because of a strong electromagnetic pulse induced when the lamp
> ignites).  We plan to follow this advice and turn off all the
> electronics in the immediate vicinity of the power supply , but how far
> (literally) do we have to go in shutting down electronics in the room.
> For instance, must we turn off a computer monitor that is  ~8 feet or a
> computer that is ~12 feet away from the Opti-Quip--what is a safe
> distance?  Does it matter whether or not the electronics are on the same
> power circuit as the power supply?  Does the EMP originate from the
> power supply or the lamp?  What other precautions should we be taking?
> (or am I being paranoid?).  Thanks in advance for whatever advice anyone
> can provide.

Our standard solution to this problem is to put the arc lamp
power supplies on a separate circuit and use a surge/EMI suppressor
on the line to the arc lamp power supplies. This prevents almost
all the spike related problems so I presume that most of the
noise is transmitted through the power line. However there is a
stepper motor controller which sometimes gets confused when a
lamp is ignited so it seem possible that the noise can be
transmitted through the air. This is further supported by
an incident many years ago when an early battery powered
digital multimeter was fried when a Hg lamp was ignited
nearby. I would expect that Xe lamp ignition makes a bigger
noise pulse because Xe is harder to ionize (but a helper gas
may be present in small quantities to get the arc started).

Jerry
gordon@med.unc.edu


Paul Muhlrad wrote:
> 
> (sorry if this appears twice; thought I sent it, but I don't see it on the newsgroups)
> 
> I have some questions concerning the prudent use of UV (e.g.
> mercury/xenon lamp) power supplies.  We are setting up a new microscope
> that is equipped with an Opti-Quip Model 1600 Power Supply powering a
> 200 watt mercury/xenon lamp.  I'm concerned about warnings I've read
> about turning off all other electrical equipment before firing up the
> lamp (because of a strong electromagnetic pulse induced when the lamp
> ignites).  We plan to follow this advice and turn off all the
> electronics in the immediate vicinity of the power supply , but how far
> (literally) do we have to go in shutting down electronics in the room.
> For instance, must we turn off a computer monitor that is  ~8 feet or a
> computer that is ~12 feet away from the Opti-Quip--what is a safe
> distance?  Does it matter whether or not the electronics are on the same
> power circuit as the power supply?  Does the EMP originate from the
> power supply or the lamp?  What other precautions should we be taking?
> (or am I being paranoid?).  Thanks in advance for whatever advice anyone
> can provide.
> 
> Paul
> --
> Paul Muhlrad
> University of Arizona, Department of Molecular and Cellular Biology
> 415 Life Sciences South, Tucson, AZ  85721
> 
> pmuhlrad@u.arizona.edu  |  (520) 621-9135  |  fax (520) 621-3709
> http://www.mcb.arizona.edu/wardlab