Sounds like a great class, where you have to block the door to keep the
students from leaving. What was the class and who sponsored it? A
mandatory safety class perhaps?

Roy Lewallen, W7EL

Watson A.Name - Watt Sun wrote:

I gotta tell you what happened at work last week. The head of
security came over and told us that someone had complained that one of
our tables was blocking the door (it's a temporary setup). The head
of registration told him that she put it there to keep the students
from leaving. The security guy says, but that's an emergency exit,
see that sign up there?

So she says, oh, ok. Well, then, can we move the sign?

:-)))

"Sven Franklyn Weil" wrote in message
...
In article , Randy and/or Sherry wrote:
At three watts on an edison base - the NE-40 is an impressive Neon bulb.
(and yes it runs fine on 120VAC - in fact it'll fire at about 85V)

I keep forgetting about those decorative neon flicker bulbs - the ones
with two closely positioned plates cut out in the shapes of crosses,
stars of David, fish, women, flames, etc.

I've got one of those (somewhere) with R. Crumb's "Keep on Truckin'" guy as
the filament...bought in the 70's, still worked the last time I plugged
(screwed) it in.

jak


Those are so delicate that one little tap can send one of those lamps into
convulsions and possibly premature failure.

I had a set of the flames in a menorah and every year there's one or two
that just ... go out...maybe they're all too close together (about inch or
two apart).

Isn't there an issue with capacitance between those bulbs if they're close
together that causes them to go nuts?

--
Sven Weil
New York City, U.S.A.

030902 1644 - nobody wrote:

In wrote:

But in 1978 I wired the 2 bulbs in the each of the EXIT
lights in the church in series.

Congratulations, you probably bypassed a safety feature. If they're in
parallel, if one burns out the other keeps going. In series, if one
goes they're both out, and the exit sign is no longer visible.

Also, they should be checked to see if they still work properly when the
power goes out and the battery system takes over.

indago wrote:

030902 1644 - nobody wrote:

In wrote:

But in 1978 I wired the 2 bulbs in the each of the EXIT
lights in the church in series.

Congratulations, you probably bypassed a safety feature. If they're in
parallel, if one burns out the other keeps going. In series, if one
goes they're both out, and the exit sign is no longer visible.

Also, they should be checked to see if they still work properly when the
power goes out and the battery system takes over.

The signs I am familiar with used a different set of bulbs for
battery operation, so they could be bad and you wouldn't know, without a
monthly test.
--


Michael A. Terrell
Central Florida

Jeffrey D Angus wrote:

wrote:
[ snip ]

Now with the above facts in mind, which do you think is safer?

That's the same logic that dictates about how much money the
school board can save by NOT installing fire sprinklers in a
school building.

Jeff


There's always those who will snipe at posts. But geez, man,
at least get the sniping right. What you quoted is a question.
See, it even has a question mark at the end. If you want to
attack the logic, then attack the part of the post that presents
the logic used. I'll make it easy for you: the facts are that
the bulbs were burning out 3 - 4 times a year. The logic applied
was that 3 - 4 failures per year per light over the course of 25
years yielded the 525 "ladder trips".

And, by the way, neither the question you quoted, nor the
snipped material mentioned saving money or eliminating
anything, other than the failures and consequent repairs.

Nor does your post add anything to the discussion, which
has to do with lamps. Sheesh - try to illustrate how reducing
voltage to a lamp increases longevity and you get a bunch of
uninformed bull****. F.Y.I. - the place has been inspected yearly
by the fire officials and passed every time.

On Wed, 3 Sep 2003 03:31:59 -0700, Watson A.Name - "Watt Sun"
wrote:

The bulb savers that I used back in the '70s were varistors. They
slowed down the turn-on of the light. They were low resistance when
warm, and high when cold. There was no diode.

These were actually Metal Oxide NTC thermistors back then (not Metal
Oxide Varistors), since silicon diodes were at that time just a
curiosity in the "ELECTRICAL" world as opposed to the "ELECTROMICS"
world. The problem with the Diode or the NTC solution, is that it does
nothing to save the bulb from line transients.

I have seen actual VARISTORS being used for current regulation as
opposed to surge suppression (clipping), but only in old telephone
sets. I'm not shure of the principle behind this since a MOV is not a
temperature sensitive device, and am curious if anyone can explain.

A ballast based voltage drop, has better potential in that regard when
combined with a VARISTOR and fuse for surge suppression. So for an
extra $50.00 you get to keep your bulb longer. Hmm.

Stepan

In article , clare @
snyder.on .ca mentioned...
On Wed, 03 Sep 2003 10:15:14 -0700, Lizard Blizzard
wrote:

Ban wrote:

Watson A.Name - Watt Sun wrote:

Hey, I agree with you. But instead, I would have used higher voltage

lamps, two in parallel. Decent LEDs were hard to get back in the
'70s. Another solution might be to use neon lamps.


You mean flourescent lights. neon lamps need a high voltage
transformer. :-(

Neon lamps need a current limiting resistor, something like 47k or so,
but not a transformer. Some of the screw base neons have the resistor
built into the base. Some of the ones I've seen have a standard sized
'edison' lamp base with a glass envelope that's about twice the size of
the base. They last something like tens of thousands of hours. They
would solve the problem of burned out filaments.


The only problem is the (described) Neon lamp does not provide a high
enough light output for emergency egress signs. They tend to be a very
weak, flickering orange. Make a good pilot light, but not much more.

No, these are much brighter than a pilot light. Much bigger, too,
Since they're red, they put out the proper color light without
filtering.

But this whole neon lamp for exit sign thread is moot. The new ones
I've seen use LEDs and run off a SLA gel cell battery. Today I was
working in a hallway with an exit sign that was about a foot (.3 m)
off the floor. During the recent remodeling someone had knocked the
cover loose so I took the cover off. I found that the sandwich behind
the cover was unusual. The front layer was a clear diffuser made of
plastic, sort of like the glass they use in bathroom windows, with
bumps on one side. Underneath the glass was a thick tray with grooves
cut (or cast) into it in the shape of the letters EXIT. Each groove
had a pale yellowish rod laying in it, a bit thicker than a pencil
lead. My guess is that this is some kind of phosphorescent material
that glows when light from flames from a fire are hitting it. There
is _no_ power to the sign.

This kind of exit sign seems to be standard on all newer built
buildings. And positioning them close to the floor is standard
procedure, because exit signs above the doors become useless as the
smoke rises and fills the room.

--
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Subject: line with other stuff. alondra101 at hotmail.com
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that will give you a choice and save you money(up to half).
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Stepan Novotill wrote:

On Wed, 3 Sep 2003 03:31:59 -0700, Watson A.Name - "Watt Sun"
wrote:


The bulb savers that I used back in the '70s were varistors. They
slowed down the turn-on of the light. They were low resistance when
warm, and high when cold. There was no diode.


These were actually Metal Oxide NTC thermistors back then (not Metal
Oxide Varistors), since silicon diodes were at that time just a
curiosity in the "ELECTRICAL" world as opposed to the "ELECTROMICS"
world.

I think you have that backwards. Back then, the radio and TV sets were
still using 5U4 TOOBS for rectifiers, whereas the electrical world
already had equipment with SCRs up to the size of hockey pucks that
could handle up to 1200 amps (http://www.cehco.com/sda.htm), and 1N1184
series of 35 amp stud mount rectifiers were common in equipment
(http://dkc3.digikey.com/PDF/T032/0547.pdf). And your average battery
charger had diodes in it, it just so happened that the manufacturers
were still stuck back in the "Stink Stack" days, still using selenium
rectifiers.

The problem with the Diode or the NTC solution, is that it does
nothing to save the bulb from line transients.

The NTC worked well because most bulb failures occurred during turn-on.

[snip]

Stepan

On Thu, 04 Sep 2003 14:36:25 -0700, the renowned Lizard Blizzard
wrote:

The NTC worked well because most bulb failures occurred during turn-on.

But soft-starting does not extend bulb life significantly in most
cases. Voltage reduction is what does the trick.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

I think that furthermore, the few volts lost in the NTC aslo goes a
long way to extending bulb life, regardless.

s

On Thu, 04 Sep 2003 22:53:34 GMT, Spehro Pefhany
wrote:

On Thu, 04 Sep 2003 14:36:25 -0700, the renowned Lizard Blizzard
wrote:

The NTC worked well because most bulb failures occurred during turn-on.

But soft-starting does not extend bulb life significantly in most
cases. Voltage reduction is what does the trick.

Best regards,
Spehro Pefhany