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Red Shift (Mar 01 2011)
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Bill Walker Send message Joined: 4 Sep 99 Posts: 3868 Credit: 2,697,267 RAC: 0 |
SockGap, in North America one phase is 120V theoretical (115V in practice usually). The failure you describe would "only" be 230V to 240V here. In any case, properly designed circuit protection should catch either the 240V or 415V failure before a fire. Your biggest worry is frying people, not boxes or wires. The argument in favor of 115/120V is that failures are more benign, therefore us users can be more dumb. (We need all the help we can get here.) Chris, it depends on the battery type, and what the manufacturer says. NiCad definitely needs conditioning when new, and then regular deep cycling, but newer lithium based batteries should be much more tolerant of abuse. |
Wiggo Send message Joined: 24 Jan 00 Posts: 36791 Credit: 261,360,520 RAC: 489 |
SockGap, in North America one phase is 120V theoretical (115V in practice usually). The failure you describe would "only" be 230V to 240V here. In any case, properly designed circuit protection should catch either the 240V or 415V failure before a fire. Your biggest worry is frying people, not boxes or wires. The argument in favor of 115/120V is that failures are more benign, therefore us users can be more dumb. (We need all the help we can get here.) That's fine for your basic domestic lines over there though most data/server centres where you are will still use 220-240V as its much more efficient. ;) Chris, it depends on the battery type, and what the manufacturer says. NiCad definitely needs conditioning when new, and then regular deep cycling, but newer lithium based batteries should be much more tolerant of abuse. But the majority of UPS's use SLA batteries (or in my case sealed maintenance free car batteries). :) Cheers. |
Fred J. Verster Send message Joined: 21 Apr 04 Posts: 3252 Credit: 31,903,643 RAC: 0 |
--[snipped]--
In Europe, they are upgrading, voltage from 220V to 240V, in steps of 2V and 3V, every year, the advantage is more power (Watts), without having to increase mm^2, of the power lines. Many years ago, I always used a 12VDC to 220VAC, transistor/thyristor converter, when camping at a (remote) place without a 220V(AC) power socket. And used a car or truck battery (Lead-Acid)or(SLA), only options in those days. Lithium-Ion, still is expensive, but by far the best, compaired to Ni-Cad, which do indeed need, a deep-cycle unload/load, from time to time. And does need to be swapped, after 4 or 5 years. Probably one of the reasons, why mobo's use Li-Ion batteries. |
Gary Charpentier Send message Joined: 25 Dec 00 Posts: 31009 Credit: 53,134,872 RAC: 32 |
SockGap, in North America one phase is 120V theoretical (115V in practice usually). The failure you describe would "only" be 230V to 240V here. In any case, properly designed circuit protection should catch either the 240V or 415V failure before a fire. Your biggest worry is frying people, not boxes or wires. The argument in favor of 115/120V is that failures are more benign, therefore us users can be more dumb. (We need all the help we can get here.) Most likely they have 3 phase 208V or two phase 240/480V |
KWSN THE Holy Hand Grenade! Send message Joined: 20 Dec 05 Posts: 3187 Credit: 57,163,290 RAC: 0 |
--[snipped]-- Mmm, Fred: M/b's don't use Li-ion batteries, they use Lithium-Manganese di-oxide one-shot batteries, because the battery is only there to maintain the BIOS information. (very low drain, and only when the computer is off...) . Hello, from Albany, CA!... |
Tom95134 Send message Joined: 27 Nov 01 Posts: 216 Credit: 3,790,200 RAC: 0 |
I've never had one "burp" the attached equipment due to a test cycle. Even when it is a deep (80~90%) test cycle. All our UPS are APC. Obviously this is not a problem with the UPS. I wonder just how hot it gets in your power closets to crack the plastic cases. |
Tom95134 Send message Joined: 27 Nov 01 Posts: 216 Credit: 3,790,200 RAC: 0 |
SockGap, in North America one phase is 120V theoretical (115V in practice usually). <snip> It hasn't been 120 volts in the United States for years, and years. The actual voltage is 117VAC based on a single phase of a three phase line. |
John McLeod VII Send message Joined: 15 Jul 99 Posts: 24806 Credit: 790,712 RAC: 0 |
SockGap, in North America one phase is 120V theoretical (115V in practice usually). <snip> I believe the specification is +/- 5 Volts. The voltage at my house is almost always 120V. BOINC WIKI |
buck_on_bass Send message Joined: 22 Jul 00 Posts: 12 Credit: 8,589,593 RAC: 24 |
As some Valve Regulated Lead Acid (VLRA) batteries age, they experience a phenomenon known as plate growth. Excessive heat is not required for plate growth to occur. This makes the plastic battery case swell. In extreme cases, the cases crack and split. This is more common with the low cost, low capacity batteries. I've seen plate growth and cracked cases in small batteries (12 volt, 4 amperehours) up to larger batteries (12 volt, 100 amperehours). The latter units were about 100 pounds. The valves in these batteries are pressure relief devices to prevent the cell from building up pressure and exploding in abnormal conditions while keeping the water and electrolyte in the cell during normal operation. |
W-K 666 Send message Joined: 18 May 99 Posts: 19401 Credit: 40,757,560 RAC: 67 |
--[snipped]-- Now that is strange because in the UK we are supposed to be dropping from our traditional 240V to 230V to be in line with a common European standard. |
Grant (SSSF) Send message Joined: 19 Aug 99 Posts: 13854 Credit: 208,696,464 RAC: 304 |
Now that is strange because in the UK we are supposed to be dropping from our traditional 240V to 230V to be in line with a common European standard. Yep. Here in Australia it used to be 240V, but a couple of years ago it was dropped to 230V to match some international standard. Ah, here we go "As of 2000, the mains supply voltage specified in AS 60038 is 230 V with a tolerance of +10% -6%.[4] This was done for voltage harmonisation" World mains voltages. Grant Darwin NT |
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