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