This I like. From: Carl Peterson Sent: Wednesday, April 10, 2019 2:57 PM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] DC/DC converter question
My rule for -48 plants is we label the - side -48 and the + side RET. Then I get a hammer and beat "positive is positive and negative is negative" into my techs heads. I also like to do Black for RET and white for -48. On Wed, Apr 10, 2019 at 3:49 PM Adam Moffett <dmmoff...@gmail.com> wrote: There's an IEC standard where you use +blue and -gray for a -V DC system. I'm sure we can find a document somewhere saying -Red for a -V DC system. I read a book when I was around 10 or 11 that said red was positive, and that stuck with me forever. Then I learned about AC where red was a second hot when you need 2 phases or a 3-way circuit. When you get multiple DC circuits in one box it seems more dangerous to follow "standard" colors than not to. So I'm not gonna bag on anybody for preferring one way or another as long as they're self consistent. Some future generation might thank you for putting a label somewhere that says "+" or "-". When you get into someone else's box, Red is just a color, and you better get your multimeter out and check. Assume makes an ass out of u and me. Mostly me. It also blows up your equipment and trips breakers. I guess if someone labeled a wire as "+" I'd be more likely to believe it, but you never know who came after and thought it was wrong and decided to "fix" it. I'm not trying to lecture the EE about electricity. Just shouting at the wind I guess. On 4/10/2019 4:16 PM, Ken Hohhof wrote: > I have a couple sites where I used purple or blue for -48, but I have spools > of red/black zipcord that I use a lot, and I assign red to voltage > independent of polarity, so that black is ground. Then even if I use single > wires, I make red voltage and black return in order to be consistent. > > I think it would be even more confusing to have red be ground and black > be-48V. Especially at mixed voltage sites that also have +24V. > > > -----Original Message----- > From: AF <af-boun...@af.afmug.com> On Behalf Of Adam Moffett > Sent: Wednesday, April 10, 2019 3:08 PM > To: af@af.afmug.com > Subject: Re: [AFMUG] DC/DC converter question > > Some people use red for negative on -48V systems. > I've got a -48V Alvarion Wimax thingamabob with a red and black pigtail > coming out the back and the red is clearly labeled negative. > > So yeah, can't go by color unless you put that color there. > > > On 4/8/2019 3:31 PM, Christopher Tyler wrote: >> Turns out the whole shelter's bus was wired backwards when we got it. Red > is negative and black is positive. Not sure what the ground is relative to, > not sure it really matters at this point but I'll check that out when I go > out there later myself. > > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > > -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- Carl Peterson PORT NETWORKS 401 E Pratt St, Ste 2553 Baltimore, MD 21202 (410) 637-3707 -------------------------------------------------------------------------------- -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
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