UPS electrical problem

[Dan Jenkins]

  On 6/29/2010 10:01 PM, Ben Eisenbraun wrote:
> On Tue, Jun 29, 2010 at 09:54:52PM -0400, Dan Jenkins wrote:
>>    On 6/29/2010 9:33 PM, Greg Rundlett (freephile) wrote:
>>> Within the past week, when the household thermostat kicks on or off the
>>> central A/C system, the PC shuts off instantaneously.
>> In my experience, that is usually a sign that the UPS battery is shot.
>> On any power twitch, the UPS switches over to the battery, which has no
>> capacity, and shuts everything off. How old is the UPS' battery? The
>> Backups Pro 500 is a fairly old model, as in Windows 98 era, if I recollect.
> That would be my guess as well, but the other thing to check is that most
> of the APC models have user-settable voltage cutover points for over/under
> current events.  It's possible that if the under-voltage setting is too
> low, then the UPS battery might still be good, and it's just that it's not
> cutting over soon enough and the PC power supply can't survive the dip,
> which causes the machine to reboot.
>
> Last I looked, APC had Windows/Mac clients for checking/changing their
> settings, and I think there are some 3rd party linux/UNIX tools that will
> allow you to do it as well.  Network UPS Tools (NUT) is one I have used in
> the past.
On some of the older UPS models, there were dip switches on the back for 
the cutover.
That is a good point, if there is enough load and the PC power supply 
can't handle any dropout.

I have an old IBM server which will survive the lights going off & on 
(it doesn't have a UPS).
Some of my newer units can't handle even a flicker of the power. Cheaper 
power supplies.

-- 
Dan Jenkins, Rastech Inc., Bedford, NH, USA, 1-603-206-9951
*** Technical Support Excellence for four decades.