All, The hardware designer may be extracting the -36Vdc from the dc/dc ratings found on the half brick, quarter brick converter specifications used to derive 3.3V, 5.0V, etc. My two cents. -John Loiselle
-----Original Message----- From: nebs-appro...@world.std.com [mailto:nebs-appro...@world.std.com]On Behalf Of Don Robert House Sent: Tuesday, November 19, 2002 8:12 PM To: nebs@world.std.com Subject: RE: 48Vdc tolerance -36 is rediculus... no battery plant is going below 40 volts... alas specifications cause much in wasted dollars... Just like the military. Don >I have all of the checklists and the widest range I found was -40 to >-57.5Vdc. One of the hardware designers here recalls a Bellcore spec that >included a range to -36Vdc. > >I haven't found it yet. If I do, I'll post it. > >Thanks for all of your responses, they all support the -40Vdc limit (so >far). > >Jack > >-----Original Message----- >From: Joe Finlayson [mailto:jfinlay...@telica.com] >Sent: Tuesday, November 19, 2002 4:28 PM >To: 'nebs@world.std.com' >Subject: RE: 48Vdc tolerance > > >Jack, > > -40VDC to -56.7VDC rings a bell. I believe I got the -40VDC (1 >minute soak) as a worst case from the SBC TP76200MP document and the 56.7 is >standard based on +5% of the -54VDC C.O. float voltage. I believe you'll >also find the 56.7 value in SBC's doc as well. I can't say I can recall any >other specs off the top of my head that go outside of these ranges, but >someone else may be able to cite another standard. I shoot for -40 to -60. > >Thx, > > >Joe > >-----Original Message----- >From: jmur...@quantumbridge.com [mailto:jmur...@quantumbridge.com] >Sent: Tuesday, November 19, 2002 2:41 PM >To: nebs@world.std.com >Subject: 48Vdc tolerance > > >Has anybody any information on the required operating range for equipment >with respect to -48Vdc power? I'm looking for Telcordia requirements >outside of the NEBS requirements that apply. > >Thanks, > >Jack -- Don R. House, Technical Representative
