Text 14104, 116 rader
Skriven 2006-11-18 19:09:42 av mike (1:379/45)
  Kommentar till text 14099 av RobertB. (1:379/45)
Ärende: Re: UPS weirdness
=========================
From: mike <mike@barkto.com>


btw, just turned on the clothes dryer, voltage dropped from 116 to 114.

For grins I also just turned on the electric oven.  114 to 113.

 /m

On Sat, 18 Nov 2006 17:15:17 -0500, "RobertB." <rb28@nyu.edu> wrote:

>In article <dhtul2l6e6vab4k0c5um3j4q4b9lvlgkoj@4ax.com>,
> mike <mike@barkto.com> wrote:
>
>> On Sat, 18 Nov 2006 14:43:15 -0500, "RobertB." <rb28@nyu.edu> wrote:
>>
>> >Any EEs out there or people who know electricity? I have two APC UPS
>> >SmartUPs in my office, a smallish 750 VA unit attached to my G4 iMac and
>> >a large 1000VA unit attached to my ancient Micron and my new iMac
>> >core2duo (Yowza!).
>> >
>> >Here's the deal. Previously, I used to not turn the Micron on much so I
>> >would shut the large SmartUPS off at night (since the computer was only
>> >on a couple of days a week at most). However, the new iMac, like all
>> >Macs, has an Energy Saver feature, so I simply put it to sleep at night.
>> >Easy. When it's on, the usage light on the large SmartUPS doesn't even
>> >go on, the machine is energy efficient. (The Micron, which has a couple
>> >of externals attached causes it to move up one notch). So there's no
>> >real voltage draw. OK. I noticed, twice now, that in the morning when I
>> >come into the office, the Voltage Trim light is on, indicating high
>> >voltage on the line. However, it only appears on one of the SmartUPS.
>> >Both machines are in the same room and, as far as I know, connected to
>> >the same circuit. After a while, the Trim light goes out.
>> >
>> >FYI, about two weeks ago, the same thing happened one night to the 750VA
>> >UPS. The Voltage Trim light was on for several hours, then went out. I
>> >have no idea why it would affect one UPS and not the other,
>>
>> One UPS might have a slightly different threshold to enable the trim
>> capability.  For example, the UPS may switch over to trim mode when the
>> voltage is over 132 volts (+/- 2%).  So one UPS may switch to trim mode
>> at 133 volts, the other at 129 volts.
>
>Oh, that's interesting. They are the same model, not sure if the specs
>are identical.
>
>>
>>
>> > why it seems
>> >to happen on a regular basis, and why it would come and go.
>>
>> The voltage may be higher in the morning when the load is low.  I know
>> the voltage in my house is high (122 volts) until around 6:45am or so
>> when lots of people start waking up.  Then the voltage starts the
>> descent for the day, the lowest being early evening, or when I run my
>> electric clothes dryer...).
>
>Isn't high voltage usually the result of something happening on the
>mains. The local transformer down the street or something?
>
>>
>> > The owner of
>> >the building (an old tenement) installed a new boiler about six weeks
>> >ago and I'm wondering if they did something weird.
>>
>> A new boiler could be more efficient in its electrical usage, reducing
>> the load on the system, therefore increasing the voltage.  Or, they
>> could have run a new electrical line for the new boiler (this is done if
>> the old stuff wasn't quite up to spec).  The new boiler connection to
>> the main electrical line could be on the other phase from your office.
>> Which will result in a very different voltage pattern in your office,
>> i.e., when the furnace goes on you office voltage will increase. (long
>> story, I can explain if you want...)
>
>Not sure I'd understand it if you did. <g> Been a while since I opened a
>physics textbook. <g>
>
>>
>> > At one point this
>> >summer they were running new cabling up the walls on all the floors, but
>> >I have no idea if they ever connected the stuff.
>>
>> They don't run cabling for their health. :)   Chances are they connected
>> it to something. Was it power cabling, or data cabling?.
>
>Power cabling. New BX cable. Not sure why, exactly, but probably to meet
>some code requirement. They don't do anything here unless they
>absolutely have to. Actually, they ran it inside a trough in the
>hallway.
>
>
>>
>> >I can't figure it out.
>> >The voltage trim light just went out about 10 minutes ago. Bizarre.
>>
>> I only touched on a few of the possibilities.  When I had a similar
>> problem in my office, I had to rent a Dranetz power analyzer to help
>> track the root cause down. (http://www.dranetz-bmi.com/) Turns out there
>> was an issue at the main breaker box for the building.  Once that was
>> fixed, everything was fine.
>
>Yeah, a friend recommended one of those. How much do those things cost?
>
>> P.S.  I would never use an APC UPS on any piece of equipment I care
>> about.  But that's just my opinion....
>
>Oh boy. I can't tell you the number of arguments this has generated in
>the past (I remember the old Canopus on Compuserve, where there were a
>couple of long-running battles about UPS device). A lot of people like
>Tripp-Lite (I still have a couple of their voltage conditioners), but
>APC is easier to come by. They're supposedly very good, but I'm no
>expert. I'm not sure any of the other companies make SoHo hardware in
>this range.

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