Frequency would be extremely rare for -40Vdc... probably once in 30 years. Duration is hard to estimate because the voltage would slowly deteriorate to that point. The rate depending on the design of the battery plant. I would estimate about 12 hours being maximum duration before the problem would be rectified from the beginning of the outage. So depending on the size of the plant and equipment current drain ... Probably only the last hour would be at the low -40Vdc point.
Regards, Don -----Original Message----- From: Dave Machado - Network Service Providers Division [mailto:david.mach...@uk.sun.com] Sent: Monday, February 19, 2001 2:51 AM To: dho...@excelsus-tech.com Cc: arthur.bl...@eng.sun.com Subject: RE: CO Battery output voltage range Many thanks Don for providing a real world view on my query. What is "real world" duration/frequency of occurances of -40Vdc low limit. regards {} From: Don House <dho...@excelsus-tech.com> {} To: "'Dave Machado - Network Service Providers Division '" <david.mach...@uk.sun.com>, "'nebs@world.std.com '" <nebs@world.std.com> {} Subject: RE: CO Battery output voltage range {} Date: Fri, 16 Feb 2001 19:37:55 -0800 {} MIME-Version: 1.0 {} {} Sorry to provide a personal answer but in 36 years of measuring CO battery I {} have never seen it fall below 46 volts and never more than 52 volts. This {} is regular plant voltage. Some special service equipment bays provide as {} much as -72 volts and -130 volts for special circuits. {} {} A typical plant of many LARGE 48 volt batteries receives a float charge of {} -51 to -53 volts from the commerical power supplied through large power {} rectifiers. If commercial power is lost and the standby generator fails, {} the battery plant will provide -48 volts for quite some time before it {} starts to drop to -46 volts. During a disaster it might be possible to drop {} below that but even during the long dropouts in Chicago I never saw plants {} to drop below -46 volts. This of course depends on the plant design and the {} reliability of the standby power system. {} {} My hat is off to Dave Spencer for looking up all of those requirements. If {} I measured -57 volts I would think something is very wrong. Same with -40 {} volts. {} {} Old Don {} {} Nice work!!! {} -40.5 to -57.0 VDC ETS 300 132-2:1996 {} {} -42.75 to -56.7 VDC ANSI T1.315:1994 {} {} -40.0 to -57.5 VDC AT&T NEDS 9069:1999 {} {} -42.5 to -56.5 VDC GR-499:1995 (-40.0 to -57.7 objective) {} {} {} {} -----Original Message----- {} From: Dave Machado - Network Service Providers Division {} To: nebs@world.std.com {} Cc: david.mach...@uk.sun.com {} Sent: 2/16/2001 1:46 AM {} Subject: RE: CO Battery output voltage range {} {} Hello Tom K, Don H, David S {} {} Thanks for this very valuable summary. {} {} I do believe that there are two other relevant items worthy of note {} in this matter, they are {} {} 1) where is the voltage being measured, and {} {} 2) what is "real world" duration/frequency of occurances {} of -Vdc low limit. {} {} {} I will address item 1 here. {} {} Can you gentlemen shed some light on duration/occurances per year of {} -40Vdc {} appearing at products input power connectors or at the power {} distribution {} frames (PDFs)? Is it greater than 3 hours? Thanks {} {} GR 499 {} -42.5 to -56.5 VDC is measured at the power distribution frame. {} {} -40.0 to -57.7 objective is measured at the input connector of {} Product (shelf level computer, line card bay, {} etc). {} {} -42.0V minimum and 56.7V Vdc maximum are respectively the {} mandated {} low (discharge) and high (charging) limits of the power plant {} operating voltage measured at the at the battery stack(s). {} {} {} ETSI 300-132-2 {} {} Is vague about where the voltage may appear (be measured), {} due to the element of negotiation required (supplier/buyer) {} to define location were power terminals connect to the {} system block (interface A). {} {} Thus measurement could be made at the line ups PDF or at input {} connector to computer, line card bay, etc. {} {} -40.5 to -57.0 VDC, is normal service steady state voltage {} range for dc system having nominal voltage value of -48Vdc. {} {} AT& T NEDs {} {} Is clear that -40.0 to -57.5 VDC is meausred at the lugs of {} the network equipment unit (I interpret this to mean input {} connector to computer, line card bay, etc.) {} {} end {} {} {} From: David Spencer <dspen...@oresis.com> {} {} To: "'nebs@world.std.com'" <nebs@world.std.com> {} {} Cc: daus...@coppermountain.com {} {} Subject: RE: CO Battery output voltage range {} {} Date: Thu, 15 Feb 2001 16:54:18 -0800 {} {} MIME-Version: 1.0 {} {} {} {} Hey Tom, {} {} There are a number of different flavors you can pick. For {} Telcordia, the {} {} objective in GR 499 has the widest swing. We do ours from -40 to {} -60VDC. {} {} The extra head doesn't cost us anything as it keeps us within the {} SELV {} {} limits and makes us look good to customers who wonder why the other {} guy's {} {} equipment only goes to 57.5VDC, the inference being ours is better. {} Here is {} {} a list of various standards requirements: {} {} {} {} -40.5 to -57.0 VDC ETS 300 132-2:1996 {} {} -42.75 to -56.7 VDC ANSI T1.315:1994 {} {} -40.0 to -57.5 VDC AT&T NEDS 9069:1999 {} {} -42.5 to -56.5 VDC GR-499:1995 (-40.0 to -57.7 objective) {} {} {} {} Have a Great Day! {} {} Dave {} {} {} {} -----Original Message----- {} {} From: tla...@coppermountain.com [mailto:tla...@coppermountain.com] {} {} Sent: Thursday, February 15, 2001 1:23 PM {} {} To: nebs@world.std.com {} {} Cc: daus...@coppermountain.com {} {} Subject: CO Battery output voltage range {} {} {} {} {} {} Hi All, {} {} I am trying to determine the appropriate Telcordia standard number {} and title {} {} which defines the absolute minimum and maximum acceptable output {} voltages {} {} for a CO battery plant. I suspect the range is something like 42VDC {} absolute {} {} minimum and 56VDC absolute maximum, but it would help to have a {} reference. {} {} Also, are there any RBOC generated docs that cover this? {} {} {} {} Thanks. {} {} Tom Lavka {} {} Copper Mountain Networks, Inc. {} {} 10145 Pacific Heights Blvd., Suite 100 {} {} San Diego, CA 92121 {} {} Voice:(858)410-7110 {} {} Fax: (858)410-7286 {} {} email:tla...@coppermountain.com {} {} ==================================================================== {} {} David A Machado {} Sun Microsystems {} Trinity Court {} Wokingham Road {} Bracknell, Berkshire {} United Kingdom, RG42 1PL {} {} Tel: +44 (0)1344 316741 {} Fax: +44 (0)1344 300704 {} ===================================================================== {} {} ==================================================================== David A Machado Sun Microsystems Lead Engineer Trinity Court Product Qualifications Wokingham Road Compliance Engineering Bracknell, Berkshire Network Systems United Kingdom, RG42 1PL Network Service Provider Division Sun: 13741 Tel: +44 (0)1344 316741 Fax: +44 (0)1344 300704 =====================================================================
