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Christmas lights

K

klem kedidelhopper

Jan 1, 1970
0
I've been reading the other thread about Quartz halogen lamps and have
found it very interesting. However since this is a bit off that track
I've started this new thread.

I seems like in the last few years it has become impossible to buy
small Christmas light series strings that have conventional lamps in
them. IE: When a filament goes out they all go out. I've noticed that
"something" happens to these new lamps that effectively makes them a
dead short when the filament opens. This then maintains the continuity
of the string and keeps the other lamps lit. But of course this comes
with a high price. A higher voltage is placed across each of the
remaining good lamps when this happens.

Little by little as they over cook, and each filament reaches the
premature end of it's life and opens, that lamp is essentially
replaced by another dead short, thereby running the remaining good
filaments at even a higher voltage. Naturally catastrophic failure of
all the rest of the string is inevitable and systematically occurs
unless this "shorting" action fails on a particular lamp and it
actually "opens". Then the remaining lamps are spared.

I know this is what's happening because I've tried to repair several
strings like this. Last night I looked at two identical 50 lamp
strings. One had about six lamps out with one open. There were 35
lamps out on the other, all with with shorts across them except for
one that was "open". The remaining lamps were still good.

My wife seems to think that not having all the lights go out when one
filament opens represents convenience, and trying to explain series
circuit theory to her is an exercise in futility. So anyhow I now have
one string which I've added 8 additional lamps to for a total of 58
2.4 V lamps on it. It runs a bit dimmer but it should last a lot
longer. I also now have a few spare lamps as well.

As much as it pisses me off you have to give the Chinese credit for
figuring out a way to sell more Christmas lights under the guise of
"convenience".

Does anyone know what is actually happening in these lamps to turn an
open filament into a dead short and begin this "runaway" effect? Lenny
 
K

klem kedidelhopper

Jan 1, 1970
0
http://people.howstuffworks.com/culture-traditions/holidays/christmas...

That reminds me - when I was about 11, our christmas tree lights failed due
to a faulty bulb socket rather than a bulb.  I thought I'd be dead clever,
and find the faulty socket by, carefully pushing pins through the isulation
either side, and touching them together to bypass the socket, all while
connected to the mains.

The method actually worked, and I found my dead socket without getting
shocked. Hurrah.

So I cut the wires either side of the socket.  Then bared one end, then
bared the other end, and picked up the two ends, one in each hand, to twist
them together.
Only I'd forgotten to unplug the mains.

I got 240v straight through my chest.  I was squatting down at the time, and
my legs spasmed and shot me backwards halfway across the room.  It was about
5 minutes before my heart calmed down enough to be able to breathe properly.

Christmas?  bah, humbug, its dangerous.

Gareth.

As we say here in America you literally got "knocked on your ass".
It's amazing considering some of the stunts we've all probably tried
in the interest of them being a learning experience that we're still
alive.

I remember when I was a teenager grabbing an old tube type TV chassis
off the bench on a hot Summer day. I caught 450VDC from one arm to the
other. I think that the only thing that saved me and my heart was
possibly the skin effect of my soaking wet sweaty Tee shirt. Lenny
 
J

John-Del

Jan 1, 1970
0
Surely the idea is to replace the blown bulb when noticed ??

Why wait until the situation you described develops ??

If you notice them... These miniature lamps are usually wrapped around trees or otherwise stuffed into decorative foliage, and single lamp failures often go unnoticed unless you're specifically looking for them.. Lenny's idea of adding lamps in series is a good idea. Years ago, I had an X10 setup for holiday lighting, and would run the dimmer modules for the light strings. Just dropping the brightness a bit kept them running almost forever.

My son just bought a set of similar lights that use LEDs. We'll see how long these last.
 
K

klem kedidelhopper

Jan 1, 1970
0
If you notice them... These miniature lamps are usually wrapped around trees or otherwise stuffed into decorative foliage, and single lamp failures often go unnoticed unless you're specifically looking for them..  Lenny'sidea of adding lamps in series is a good idea.  Years ago, I had an X10 setup for holiday lighting, and would run the dimmer modules for the light strings.  Just dropping the brightness a bit kept them running almost forever.

My son just bought a set of similar lights that use LEDs.  We'll see how long these last.

I took a good look at these lamps tonight under a magnifier, I
noticed a very curious thing. At the base of each lamp the thin wires
go through the bulb and attach to the posts that the filaments are
then welded to; If you look into the bulb, at the base of these posts,
inside each lamp there seems to be a thin wire wrapped around the
posts that one would think would short them out. It obviously doesn't
happen right away but after a period of time, (heating), it does seem
to. Perhaps that is it's purpose, to burn through an insulating layer
on the posts after a brief time and destroy the lamp. And one further
observation. In looking at the filaments on all the "shorted" Kamakazi
lamps It appears that the filaments never opened, rather the shorting
wire must have finally burned through the posts and shorted the lamp
out.
What an insidious clever way to sell more Christmas lights. Isn't it
fascinating the lengths that some people will go to to separate us
from our money? Merry Christmas! Lenny
 
M

Mark Zacharias

Jan 1, 1970
0
I took a good look at these lamps tonight under a magnifier, I
noticed a very curious thing. At the base of each lamp the thin wires
go through the bulb and attach to the posts that the filaments are
then welded to; If you look into the bulb, at the base of these posts,
inside each lamp there seems to be a thin wire wrapped around the
posts that one would think would short them out. It obviously doesn't
happen right away but after a period of time, (heating), it does seem
to. Perhaps that is it's purpose, to burn through an insulating layer
on the posts after a brief time and destroy the lamp. And one further
observation. In looking at the filaments on all the "shorted" Kamakazi
lamps It appears that the filaments never opened, rather the shorting
wire must have finally burned through the posts and shorted the lamp
out.
What an insidious clever way to sell more Christmas lights. Isn't it
fascinating the lengths that some people will go to to separate us
from our money? Merry Christmas! Lenny

Or, keep the remaining series string going even after the lamp burns out.

Mark Z.
 
K

klem kedidelhopper

Jan 1, 1970
0
Or, keep the remaining series string going even after the lamp burns out.

Mark Z.

Thank you Gareth. I did miss that link. So it seems that my theory
about the short,(shunt) was pretty much right on the money, except for
one thing that is. The article mentions, as I had suspected that when
the filament opens, current then flows through the shunt. This heats
the shunt, thereby causing it to melt it's way into the posts and thus
providing continuity to the series string. Although that does sound
ingenious, as I had mentioned in my last post, upon examining each
"shorted" lamp under high power magnification it appears that in
almost every case all the filaments appear to be intact. That would
suggest that this melting and subsequent shorting of the lamp occurred
before the filament opened. Naturally I couldn't measure these
filaments with the short across them to confirm this, but they do look
to be mechanically sound. So I guess what it comes down to is I think
that we're being screwed with these Christmas lights. As an
interesting side note. I have considered using some of the surviving
lamps in parallel as low voltage "street lights" and to illuminate
model buildings on my Lionel train layout. I'll be sure to fuse the
circuit if I do.... Lenny
 
M

Mark Zacharias

Jan 1, 1970
0
Pat said:
One comment on this topic... These strings with the shunts are not
new. They have been around for decades. When I was a child (a long
time ago), they used series strings of regular bulbs. If one went
out, they all did. The next advance was parallel bulbs. That solved
the problem, but they were expensive. Later (1970's?), these mini
bulbs with the shunts came out. I could be off on the decade, but it
has been a long time. In my experience, bad connections are more
common than bad shunts, but I have seen my share of actual burned out
filaments, too. With the new LEDs (now that they figured out "warm"
white), the only problem we will have is bad connections ;-)
Pat


And *really* crap quality LED's that have a shorter run life than the lamps
did.

I have had more than one cheap LED flashlight where up to 4 out of 9 LED's
quit rather quickly, even had one even strobing at a visible rate.

Bought a higher quality flashlight. About three years old now, use it daily,
still OK.

Mark Z.
 
H

hr(bob) [email protected]

Jan 1, 1970
0
I've had several like that.
I now perceive them as cheap and disposible, which is probably their
intended purpose.

(I often lose them before they break anyway)

Gareth.- Hide quoted text -

- Show quoted text -

I always add a couple of extra sockets and lamps to every string of
lights I own, both outsie and inside. That slows the failure rate WAY
down. Then, at the end of the season,I check all the strings of
lights before I put them away. THe runawa effect I have seen, it can
be quite spectacular if you are there at the right time. Eventually,
as the number of remaining working lights quickly reduces, eventually
the current gets so high that one of the shunts fails. The shunts are
actually regular wire, but with insulation that breaks down at may 50
volts. When a bulb burns out, the voltage across the open bulb rises
to the supply voltage, 120 or 240, the insulation breaks down, and the
shunt completes the circuit, lighting up the remaining bulbs.

I also have a device from 30+ years ago that starts out high
resistance and quickl, 2 -3 seconds, goes down to less than 1 ohm.
This is in the supply for the lights. This prevents the high initial
surge that occurs because the filaments are cold, and pretty much
eliminates the initial flash / failure that we are all familiar with.
 
K

klem kedidelhopper

Jan 1, 1970
0
I always add a couple of extra sockets and lamps to every string of
lights I own, both outsie and inside.  That slows the failure rate WAY
down.  Then, at the end of the season,I check all the strings of
lights before I put them away.  THe runawa effect I have seen, it can
be quite spectacular if you are there at the right time.  Eventually,
as the number of remaining working lights quickly reduces, eventually
the current gets so high that one of the shunts fails.  The shunts are
actually regular wire, but with insulation that breaks down at may 50
volts.  When a bulb burns out, the voltage across the open bulb rises
to the supply voltage, 120 or 240, the insulation breaks down, and the
shunt completes the circuit, lighting up the remaining bulbs.

I also have a device from 30+ years ago that starts out high
resistance and quickl, 2 -3 seconds,  goes down to less than 1 ohm.
This is in the supply for the lights.  This prevents the high initial
surge that occurs because the filaments are cold, and pretty much
eliminates the initial flash / failure that we are all familiar with.

But no one has addressed the fact that these filaments I've observed
under magnification on the bad lamps that I have pulled from this
string do not seem to have opened. However the lamps indeed read dead
shorted though. So just as I've suspected from the beginning the shunt
must be burning it's way through the posts and rendering the lamp
useless in spite of the lamp still having a good filament. Lenny
 
K

klem kedidelhopper

Jan 1, 1970
0
Their web site explains how it works:
<http://www.lightkeeperpro.com/How-It-Works/how-the-lightkeeper-pro-works>
Also, Wikipedia:
<http://en.wikipedia.org/wiki/LightKeeper_Pro>

--
Jeff Liebermann     [email protected]
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

I think that going forward, (from this point anyway) the answer is
that the filaments on these crappy bulbs are probably over rated, and
therefore full line voltage should probably not be applied to the
string. I'm going to buy a bunch of identical new Christmas light
strings of the same type, (on discount, after Christmas of course).
This way they will be cheap enough so that l can buy enough to be able
to cut and past extra lamps onto each string. This will essentially be
equivalent to running each string at something like 105 to 110 volts,
and this should increase the life span of the lamps substantially. In
addition I am also going to speculate that since the lamps will then
be running cooler it may keep the shunts from burning through the
posts and rendering lamps with otherwise good filaments bad as well.
This tactic may not stimulate the economy but it should keep the
Christmas light money in my pocket rather than theirs. Merry
Christmas! Lenny
 
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