[no subject]

Matthew.

On 12/22/05, Courtney Thomas <cc.thomas at earthlink.net> wrote:
> Mike,
>
> Thank you for the thorough and thoughtful reply.
>
> Unrelated questions to which I'd appreciate a response is:
>
>         can U.S. equipment made for 120v be used in Canada, which I understand
> has 220v as standard home installation ?
>
>         if no, what, if anything, can be done to render such equipment usable
> in Canada ?
>
> Again, gratefully,
>
> Courtney
>
>
>
>
> Mike Harrison wrote:
> > Courtney asked:
> >
> >>What and how do the testers reveal ?
> >
> >
> >   Disclaimer: This is potentially dangerous, don't touch anything metal,
> >   don't wear shoes with metal tacks in the heels.. don't.. (it's a long list)
> >
> >
> >   Good question. Set to AC Volts, (Alternating Current) you can test an
> >   outlet as follows:
> >
> >      The outlet should have 3 plugs.. 2 slots, one larger than the other
> >      and a round hole:
> >
> >              [ |
> >               o
> >      The larger slot on the left is 'neutral' the smaller one on the right
> >      is 'line' or 'hot' and the small circle is 'ground'.
> >
> >      In a perfect world. 'hot' has a sine wave of approximately 117 volts
> >      calculated as a 'root mean square' average of alternating electrical
> >      potential. You want to make sure it's there, and that 'neutral' is
> >      at 0 volts, as is ground.
> >
> >      So with your el-cheapo voltmeter, stick the probe tip black lead in
> >      the 'neutral' and the red lead into 'hot'. You should get 110 to 120 volts AC.
> >
> >      Then move the red lead into 'ground'. You should get 0 volts. Maybe 0.5volts.
> >      but it should be 0. Ground and neutral (in most systems) tie into the
> >      same place back at the breaker panel.. they should have the same
> >      potential.
> >
> >      Then move the black lead to 'hot'. You should get 117 volts. If not,
> >      your ground is open, not grounded. Very common problem in houses.
> >      The purpose of the ground wire is safety. The metal chassis of a
> >      device uses the ground wire as a redundant path back to the breaker
> >      box. If there is 'leakage' via EMF from high voltage electronics
> >      or transformers or.. (lots of things), it should drain down the
> >      ground wire. If it is 'open', a shock potential from the device may
> >      exist. Grounds are also a catastrophic failure protection means.
> >      If a power supply 'melts down' and shorts to ground, the current
> >      should travel back to the break panel at close to 0 volts, and if the
> >      current level is high enough, allow the breaker to trip.
> >
> >      Last test: paranoid mode. If you have something that is grounded
> >      handy, like a metal copper pipe that goes into the earth, large metal
> >      structural supports.. etc..  - Measure between it and the Ground and
> >      Neutral and make sure it's 0 volts or really really close to it. (.5volt?)
> >      and measure between the natural earth ground and 'hot' you should get
> >      110-120 volts.
> >
> > So.. If all is good, you have a properly wired electrical outlet, there is
> > one good 'idiot check' you can make on your UPS:
> >
> >      Set your meter to Ohms. A measure of electrical resistance.
> >
> >      With your UPS unplugged, put the black lead on the round pin.
> >      then put the red volt meter lead on any metal on the case.
> >      It should be under 1 ohm. Now move the red lead to the round
> >      plug hole on the outlets. Same thing. 1ohm or less.
> >
> >      On some UPS's you MAY be able to do this with 'hot' and 'neutral' on
> >      the outlet to the cord plug end for hot and neutral, depends
> >      if it's using a relay for power pass through and what it's position
> >      is when 'off'.
> >
> > Plug your UPS in and turn it on. Repeat the first set of steps for the
> > outlets on the UPS.
> >
> > Last test. turn off the power to the UPS, but keep it plugged in (so
> > ground is still attached) so that the UPS is running on batteries.
> > It may work better if something is plugged in and running off the UPS
> > as many of them require a load. Then do the tests again. You will get
> > something approximating 110-140 volts from neutral to line on the UPS, it
> > depends on the quality of the site wave your UPS generates. It may read
> > high if there is no load or a very small one, and/or it produces a squarer
> > waveform than normal line power.
> >
> > ----------------
> >
> > Honest disclaimer: I've done these tests and more.. but I usually
> > just plug them in and see if they work. :)  - I did check out the wiring in my house
> > when I bought it for proper polarity of the pins, and good grounds..
> > and again when I put in the generator and UPS's.. but I'm insane.
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
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> >
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> >
> >
> > _______________________________________________
> > Ale mailing list
> > Ale at ale.org
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<li><strong><a name="00307" href="msg00307.html">[ale] OT: question about replacing batteries in a APC UPS</a></strong>
<ul><li><em>From:</em> meuon at geeklabs.com (Mike Harrison)</li></ul></li>
<li><strong><a name="00314" href="msg00314.html">[ale] OT: question about replacing batteries in a APC UPS</a></strong>
<ul><li><em>From:</em> cc.thomas at earthlink.net (Courtney Thomas)</li></ul></li>
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