cayz@udel.EDU (James Cayz) (06/27/89)
Hi All,
I am trying to roll-my-own surge protectors, knowing that the separate
parts can't cost more than 1/10 the price of a pre-built unit....
First, I ripped apart a fully-functional Radio Shack Heavy-Duty Surge
Protector. Pretty much what I expected - a MOV, neon light & resistor combo,
and hmm, what's this thing???... Oh, this is a "block" unit, with a 3-prong
plug on one side, a 3-prong socket on another side, and a light. I plug it
into the wall, and plug a power strip into it.... Here's a diagram of what I
found inside.....
___________neon MOV is in parallel with
/ _ | Neon light and dropping resistor.
--/ \ MOV resistor Mystery Item is between connection
Mystery # \_/ / of circuit and Wide Blade and
item-> # \ / where circuit splits...
/ \_____/ Mystery Item is green, kidney
Wide | | Narrow shaped plastic(?), 0.1" in dia. x
blade | | Blade 0.3" in length (roughly cylindrical)
and has markings "LF 10A", where
O ground the "L" is large, and has the "F"
resting inside it....
Is the mystery item a fusible link, 10 amp capacity??? If so, can I
use (in leiu of finding fusible links in Delaware :-) ) Fast-Blow 10 amp
fuses (As long as I know that if I blow the fuse, I've also blown the MOV, and
should replace BOTH)????
Second, I was once told that to have decent surge protection that I
would need 3 such constructs, 1 between each pair of wires, ie Wide-Narrow,
Wide-Ground, Narrow-Ground (I _know_ that saying hot/cold or pos/neg is wrong
for AC, but I don't know what is correct, and which corresponds to the wide
blade on a polarized plug (and why)). Are 3 really necessary, or only 1,
across Wide-Narrow????
I know that this has gotten really long, but, if anyone has the time to
drop me an answer, I'd appreciate it.....
Thanx in Advance,
James Cayz
|James Cayz can be found via: USPS: Educational Technology Laboratory,
|E-MAIL (ARPA): cayz@louie.udel.edu : 203 Willard Hall Education Building,
|PHONE: +1 302 451-6307 : University of Delaware, Newark DE 19716