My understanding is that the shunts are just anodized wire wrapped
around the 2 leads of the lamp, inside the bulb. With the lamp working
the voltage differential across the leads is very low, in the order of 1
to 3 volts. When the bulb burns out the voltage differential is not line
voltage, or up to 170 volts peak, which causes the anodized layer to
puncture and short to the two leads of the lamp. Everything is fine
until the lamp is disturbed and the very small spot welds the anodized
wire made are now damaged, and because of other opens in the string
(other shunts open) can not get the 120 volts across the lamp to re-fuse
them.
If you look inside the lamp you will see this piece of wire wrapped
around the leads.\
I have a client who has me put up and take down his Christmas
decorations each year. He does not want to replace them, so for the last
6 years I have been repairing them each year before I put them up. It
costs him more to do it this way, but for some reason he doesn't want to
replace them. I try to replace all the defective lamps when I take the
lights down, but the next year I spend hours replacing lamps until I get
everything working again. Every 3 years I replace all the lamps, which
makes for a more reliable year. I hope to talk him into going with LED
lights when I take them down this year. LEDs are not a reliable as folks
think they are. Even though they have a 20,000 hour MTBF, because of the
sheer number of lights, you will have one or 2 burn out each week. For a
rather in-depth article on this subject, check out:
http://www.ciphersbyritter.com/RADELECT/LITES/LEDLITES.HTM
I know Terry and he can take the most mundane subject and spend weeks
making it fun! If you want to get your mind numbed, check out some of
his other articles. He actually developed the Motorola MC6809 "for fun"
on paper, then went to work for Motorola to build the chip.
Peace,
Pat
Thusly spake David C., On 12/5/2010 2:37 PM:
> Ok, I'll be the first to admit that I'm not up on Christmas lights and
> decorations. My primary response to the holidays, and Christmas in
> particular, is to ignore them/it to the fullest extent possible. I
> haven't bought Christmas lights in probably 25 years. Given that, I
> was under the impression that:
> 1. Pretty much all Christmas lights these days are LED; and
> 2. Series wired Christmas lights went out sometime around the middle
> of the first Eisenhower administration. Shunts? Seems like a solution
> looking for a problem.
>
--
Pat Horne, Owner, Horne Systems
(512) 797-7501 Voice 5026 FM 2001
Pat@HorneSystemsTx.com Lockhart, TX 78644-4443
www.hornesystemstx.com
-- We support Habitat for Humanity - a hand UP, not a hand OUT --
_______________________________________________
Shop-talk@autox.team.net
Donate: http://www.team.net/donate.html
Suggested annual donation $12.96
Archive: http://www.team.net/archive
Forums: http://www.team.net/forums
|