UPS in blackouts

[MikeM]

My computer is connected throiugh a UPS and a surge protector. Until
recently wherever there was a blackout the computer kept running and I
had time to close down. For the last week we have been getting a lot
of mini blackouts, the power goes off and comes back on almost
immediately, they often last for about a second or less. When this
happens the computer goes off and I have ot switch it back un. The
lights on the UPS and the surge protector seem to be indicating that
there is no problem with them. And the UPS beeps for a short time.

Why would the computer be going off with this type of blackout?

Thanks
Mike

 

[Ken]

My computer is connected throiugh a UPS and a surge protector. Until
recently wherever there was a blackout the computer kept running and I
had time to close down. For the last week we have been getting a lot
of mini blackouts, the power goes off and comes back on almost
immediately, they often last for about a second or less. When this
happens the computer goes off and I have ot switch it back un. The
lights on the UPS and the surge protector seem to be indicating that
there is no problem with them. And the UPS beeps for a short time.

Why would the computer be going off with this type of blackout?

http://www.pcguide.com/ref/power/ext/ups/types.htm

 

[geoff]

Either the UPS is old or cheap. A UPS should be fast enough to kick in no
matter if the power goes out for a while or a quick mini-blackout.

I've had the quickies also and my UPS beeps one time, I hear the click, and
then it switches back to line power, no effect on my computer, monitor,
modem, nor router (all those devices are plugged into the UPS).

--g

 

[Don Phillipson]

My computer is connected throiugh a UPS and a surge protector. Until
recently wherever there was a blackout the computer kept running and I
had time to close down. For the last week we have been getting a lot
of mini blackouts, the power goes off and comes back on almost
immediately, they often last for about a second or less. When this
happens the computer goes off and I have ot switch it back un. The
lights on the UPS and the surge protector seem to be indicating that
there is no problem with them. And the UPS beeps for a short time.

Your UPS battery has expired. They only last a couple of
years. In most brands the battery can be replaced. This
is documented in product literature given away with new UPSs.

 

[John Doe]

My computer is connected throiugh a UPS and a surge protector.

For the last week we have been getting a lot of mini blackouts,
the power goes off and comes back on almost immediately,

An Uninterruptible Power Supply isn't the only solution. We never
have blackouts here, but we do suffer from some momentary outages
(maybe also known as "brownouts"). Buying a line conditioner voltage
regulator nuked the problem. I have a cheap APC Line-R 1200VA but
would like a Tripp Lite LC-1200 (partly because it has more LED
indicators). Besides the LED indicators, I tell it works when the
speaker system that's plugged directly into the surge suppressor
makes a low-frequency pop sound but nothing happens to the computer.
If we had frequent blackouts, I might need a UPS, but a battery
backup is totally unnecessary here and I do not in any way miss
having a UPS. With a regulator/conditioner, you don't have to mess
with a battery. Some better UPSs include regulators that keep your
computer running but don't require battery power during momentary
outages.

 

[John Doe]

(maybe also known as "brownouts").

Maybe not, apparently "momentary blackout" or whatever.

 

[Paul]

My computer is connected throiugh a UPS and a surge protector. Until
recently wherever there was a blackout the computer kept running and I
had time to close down. For the last week we have been getting a lot
of mini blackouts, the power goes off and comes back on almost
immediately, they often last for about a second or less. When this
happens the computer goes off and I have ot switch it back un. The
lights on the UPS and the surge protector seem to be indicating that
there is no problem with them. And the UPS beeps for a short time.

Why would the computer be going off with this type of blackout?

Thanks
Mike

The reason the UPS works in the first place, is because
of a feature of the ATX power supply.

The main capacitor in the ATX supply stores rectified
power from the line. Say you have a 450W power supply.
The cap is designed to hold power for about 16 milliseconds,
while the output of the supply is delivering 450W. If
the motherboard and peripherals are only drawing 225W
of the available power, the cap may hold energy for
32 milliseconds.

Cheap UPS actually "glitch" the output during a line
outage. If the line power disappears for 8 milliseconds,
the UPS hasn't even started to respond yet. It takes
time to recognize a failure.

The relay should have flipped the unit to using its
inverter, before the ATX main capacitor is drained.
So in most situations, it should all work. I have
a UPS of that architecture (SPS type) and it hasn't
failed to flip in time to prevent a problem.

If the ATX main cap is weak, if the actual line
voltage is low (say 90V instead of 120V), then
the cap may not be able to hold up long enough
for the UPS transfer to complete without symptoms.

A double conversion UPS does not use the same method,
and has a truly glitchless output. The computer would
no longer be solely reliant on that feature of the
ATX supply, if such a UPS was used. A double conversion
UPS used to cost about $1000, has a fan, and runs hot
while it is working. The SPS type are cold, because
generally they're not doing anything, as long as
the AC is present. Mine is ice cold.

In a test at work, where about 100 SPS type UPSes
were purchased, about 10% failed to perform
correctly. In some cases, the power would go off
completely, and the UPS failed to switch to battery
powered inversion. The results of that test, is why
I would recommend to a purchaser, to stay away
from the "bottom tier" UPS designs. The bottom
tier are designed for lowest cost, rather than
best operation.

Paul

 

[david]

My computer is connected throiugh a UPS and a surge protector. Until
recently wherever there was a blackout the computer kept running and I
had time to close down. For the last week we have been getting a lot of
mini blackouts, the power goes off and comes back on almost immediately,
they often last for about a second or less. When this happens the
computer goes off and I have ot switch it back un. The lights on the UPS
and the surge protector seem to be indicating that there is no problem
with them. And the UPS beeps for a short time.

Why would the computer be going off with this type of blackout?

Thanks
Mike

UPS battery is bad.

 

[John Doe]

My computer is connected throiugh a UPS and a surge protector.

By the way. Make sure your UPS is after the surge suppressor, not the
other way around. The surge suppressor should be plugged into the wall,
and the UPS should be plugged into the surge suppressor.

 

[thanatoid]

My computer is connected throiugh a UPS and a surge
protector. Until recently wherever there was a blackout the
computer kept running and I had time to close down. For the
last week we have been getting a lot of mini blackouts, the
power goes off and comes back on almost immediately, they
often last for about a second or less. When this happens
the computer goes off and I have ot switch it back un. The
lights on the UPS and the surge protector seem to be
indicating that there is no problem with them. And the UPS
beeps for a short time.

Why would the computer be going off with this type of
blackout?

It should not. Your UPS is faulty. It may be worth fixing or
not. APC and TrippLite are the only good ones.

I can see a crappy power supply shutting down with this kind of
momentary blackouts but a UPS is designed to prevent exactly
that, among other things, so that's why I think there's
something wrong with yours. They are supposed to respond in
milliseconds. You may just need one part on your UPS's circuit
board replaced.

 

[John Doe]

It should not. Your UPS is faulty. It may be worth fixing or not.
APC and TrippLite are the only good ones.

I can see a crappy power supply shutting down with this kind of
momentary blackouts

I don't believe there are any ordinary PC power supplies that can
handle a significant power interruption.

but a UPS is designed to prevent exactly that,

You don't know whether it's a complete loss of power or a brownout.
If it's just a major dip in voltage or probably even an extremely
short complete loss of power, a less expensive and more reliable
regulator would work better.

 

[ToolPackinMama]

My computer is connected throiugh a UPS and a surge protector. Until
recently wherever there was a blackout the computer kept running and I
had time to close down. For the last week we have been getting a lot
of mini blackouts, the power goes off and comes back on almost
immediately, they often last for about a second or less. When this
happens the computer goes off and I have ot switch it back un. The
lights on the UPS and the surge protector seem to be indicating that
there is no problem with them. And the UPS beeps for a short time.

Why would the computer be going off with this type of blackout?

Maybe it needs a new battery.

 

[westom1]

My computer is connected throiugh a UPS and asurgeprotector. Until
recently wherever there was a blackout the computer kept running and I
had time to close down. For the last week we have been getting a lot
of mini blackouts, the power goes off and comes back on almost
immediately, they often last for about a second or less. When this
happens the computer goes off and I have ot switch it back un.

Paul and only a few others have provided the useful answers.

1) UPS battery dead? Pull the UPS plug. Does it still power the
computer? You only implied it would - did not state so. A necessary
test before even considering anything else.

2) All power supplies are required by Intel standards to continue
power to a computer when AC power is lost. This even necessary
because, as others have noted, the UPS needs time to decide that power
was lost. An inferior power supply (missing essential functions) may
not provide power long enough when AC power is lost. Was it a
discounted power supply so often marketed to computer assemblers?

3) Other functions in the power supply make other electrical
anamolies irrelevant. Again, did that power supply contain those
other essential functions?

Two suspects and three questions to identify which suspect is
defective.

 

[John Doe]

haha

surprise

 

[John Doe]

If you have a good quality UPS with a fast transfer time, you
definitely don't need a surge protector before the UPS.

He already has a surge suppressor.

The UPS has surge protection

Yeah, but having the extra surge suppression doesn't hurt.

 

[westom1]

Yeah, but having the extra surge suppression doesn't hurt.

If a UPS already has surge protection, then 'extra' does nothing but
hurt the pocket.

John Doe also does not explain why a power strip protector must not
be plugged into a UPS. That would require technical knowledge or an
admission that the UPS outputs some of the 'dirtiest' electricity when
in battery backup mode.

These UPS generated spikes are so high and so frequent as to be
harmful to the UPS or a power strip protector - when used together.
But those same voltage spikes and harmonics are completely irrelevant
to computers. Why? Computers contain robust surge protection. Those
UPS generated spikes are not harmful to electronics but can be harmful
to typically undersized power strip protectors. John Doe forgot to
mention underlying facts that require technical knowledge.

 

[westom1]

UPS is designed to prevent exactly that, among other things,
so that's why I think there's something wrong with yours.

John Doe is making recommendations rather than suggesting how to
discover the problem. Nobody can answer this question until the UPS
power plug is disconnected to learn if the computer keeps working.
Without that simple test, John, et al will blame this or that or the
other thing rather than suggestions how to discover what is actually
defective.

thanatoid has accurately posted that some crappy supplies could
shutdown. Industry standards have long stated how long power can be
removed without crashing any computer. So that a UPS does not crash a
computer when switching to batteries, a computer power supply must
output power with no incoming power. A crappy 'marketed to computer
assemblers' power supply may not do that.

 

[geoff]

JDoe is a bit of a troll in these groups but as far as using a power strip
as a surge protector is like doubling up on your condoms. Being doubled
rubbered can't hurt and provides extra protection in case one rubber breaks
but I guess it depends on how paranoid you are.

--g

 

[westom1]

JDoe is a bit of a troll in these groups but as far as using a power strip
as a surge protector is like doubling up on your condoms.

That reasoning works when one does not know what a surge protector
does. Indeed, if a surge protector works by stopping or absorbing
surges, then it would work like a condom. Problem: surge protectors
do not work that way. A protector is only as effective as its earth
ground. How to make one or fifteen protectors work better? Upgrade
the earthing. Shorten the connection to earth. Only use single point
earth ground. Do what is routinely done in any high reliability
facility.

Surge energy must go somewhere - which is what surge protection is
all about. Do those tens or hundreds of thousands of joules get
stopped by a 480 or 1000 joule protector? Of course not. Protection
is about diverting surges into earth. That energy is harmlessly
dissipated in earth. One or fifteen protectors would do the same
thing. How those one or fifteen protectors are connected to earth
ground - that is where surge protection gets improved. Nothing new.
This was understood even 100 years ago. And this is what the informed
do when a protection system fails - first inspect and fix the
earthing.

John Doe a troll is an understatement. Review his reply to
thanatoid. He says:

... more reliable regulator would work better.

What regulator? Discussed was a UPS and power supply John Doe's
technical knowledge is near zero which is why his posts are heavy on
subjective speculation and light on what specifically one can do.
Where is this regulator that would solve the problem? He invents as
he posts. There is no regulator in the relevant circuits. There is a
power supply or a UPS. Both either have enough reserve power when AC
is lost or do not. Regulator has nothing to do with energy storage.
John Doe does not even know that. So why is he posting?

 

[geoff]

I agree, the surge does not get 'stopped' it takes the shortest path to
ground, and it sometimes jumps systems to do that.

I had a lightning strike in the front of the house, four houses total were
affected. It blew out several things including my cable modem, router, and
UPS, but the computer itself was unharmed.

The surge also blew a flexible metal tube that delivers gas to the hot water
heater. When I looked in the closet, the tube was flopping around with a
flame coming out of it.

--g