UPS Liebert powersure PST 650 doesn't start

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This is a 6 year old (now discontinued) UPS.
See http://www.liebert.com/product_pages/Product.aspx?id=1
The user manual for the Australian version is here
http://www.powerqualityconsultants.com.au/uploads/Files/Liebert_Powersure_PST_Assistant_-_User_Manual.pdf

It died during the night.
I've disconnected the outputs, so there's no load. Pressing the power button
causes the red fault light and the green battery light to flash briefly and you
can hear a relay click once, then nothing. The overload circuit breaker hasn't
popped and I replaced the battery a year ago, so that should be OK.

I hesitant to poke around inside given the mains voltages that are generated (or
supposed to be generated) unless I know what I'm looking for.

Can anyone give me a clue as to where to start?

Thanks

Re: UPS Liebert powersure PST 650 doesn't start
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http://www.powerqualityconsultants.com.au/uploads/Files/Liebert_Powersure_PST_Assistant_-_User_Manual.pdf
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Nothing specific.

If you remove the battery, disconnect the device from the mains, and
leave it for half an hour, there should be no risk in taking it apart.
You could then check for continuity of any internal fuses, for shorted
FET switching transistors (i.e., the ones on big heat sinks), and
continuity of the transformer coils.

I have managed to repair a UPS, though it's highly debatable whether it
was economically worthwhile, given that these things are so cheap now.
In addition to the cost of replacement components, it also took
considerable time.

Sylvia.

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http://www.powerqualityconsultants.com.au/uploads/Files/Liebert_Powersure_PST_Assistant_-_User_Manual.pdf
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I'll just add that if you do reach the point of wanting to power it up
with the case removed, make sure you use eye protection. As I
discovered, these things can blow quite dramatically (however, I was
using eye protection).

Sylvia.


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Very likely dead battery if its a few years old.
I have seen a few Eaton Powerware ones with dead batteries that are
less than 2 years old.

If you unplug it from the mains, and disconnect the battery terminals
with an insulated tool (such as pliers), it should be safe to work on

To check the battery, you might want to leave it on overnight with no
load, to give the battery a charge.
Unplug from mains, and check  that the battery has held the charge.
Turn on the UPS own switch (dont plug in)
and measure the battery voltage.

(Note - as there may be 240v potential on the battery terminal(s) at
this time, care should be taken when using test leads by using a
method that avoids you touching the terminals or any other part of the
UPS with your body.)

If the battery is bad, voltage will likely drop off over a few seconds
to about 10.5V  or so, at which point the UPS will likely shut down.

If this is the case, replacing the battery should fix the problem.


Also, As Sylvia also says - you should consider whether it is
worthwhile to replace the UPS, compared to a repair unless there is a
reason for keeping this unit.
By the look of this UPS, it probably has a 12v 7AH battery or
thereabouts.  This will cost around $40 to buy and according to the
webpage you provided - it is user replaceable.



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On investigation I found that the sealed lead acid battery, which I had
installed less than a year ago, had been leaking. By design, the battery was
mounted on it's side rather than upright which presumably didn't help.

This is the first time I've seen a leaking SLA battery. Would this be
symptomatic of severe overcharging?



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more symtomatic of the wrong type of battery.
look up the datasheet ofr the battery and see if such use is allowable

--
⚂⚃ 100% natural


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Couple of weeks back I would have been surprised, but now, I am not.

I saw one last week seeping out of one of the terminals in an Eaton
powerware 5110.
It was from the - terminal and this would be at the down position when
installed.
The leak had occured around the terminal and the plastic surrounding
it. it was enough to wet the area near
the terminal and corrode the spade lug and terminal badly.

Some years back I saw one leaking in a similar SLA that was in a home
alarm system (that battery
was years old though, had not been charged for some time and it was
not a real surprise.)

Considering that we have about 20 of these supplies and batteries on
the newer group (bought early 2009) started dropping dead within weeks
of each other, (while the batteries in the ones we got in 2007 are
still ok) I can only assume that its shit quality of the more modern
batteries.

We ordered some "Yuasa" ones from Farnell, as the datasheet specifies
them to be ok for this application, and lying on their side as well as
giving 5+ years of use if the specs are followed.


The leaky one was the factory installed unit.


As for the battery lying on its side, the manual with the UPS states
that it can be mounted vertically or horizontally
but I guess that is only as long as the seals hold out..

The way it is mounted in the Eaton unit - the battery would either sit
on one
end (with the terminals at top side). or lie on its side.






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I installed a new fully charged battery and used a desktop fan and then a
Dremmel tool as test loads but both ony ran at half speed. The Dremel tool
sounded rough.
.
I think I'll buy another UPS.

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Another UPS like this will do the same thing.  It is normal and it
means that the thing is looking like its working.

It sounds rough because of the UPS battery backed up output being a
square wave, or modified square wave rather than a sine wave (that the
normal power mains is).  This is probably the reason for the half
speed too. The motor does not like the waveform and is inefficient.

Electric motors and items with 50hz iron core transformers will sound
rough, buzz, may blow a fuse (my soldering station did).
This includes household fluro lamps with inductive (non electronic)
ballasts.  Modern CFL's have electronic ballasts and will work fine.


You need to check it with a non-inductive load such as a light bulb
(or CFL), computer or similar.

These UPS are not designed to run most AC motors, transformers and
such loads.  They will make noise and may run rough.

They will run fine on things like computer power supplies, most
switchmode plugpacks (ones that are small and light) etc.

If you need to backup power these sort of things you need to get a
sine wave output UPS, which will NOT be cheap - probably 3x as much or
more.
Note that this type of UPS can run just about any appliance, including
computer etc, as long as the startup surge current and UPS capacity is
sufficient.

The startup surge current is significant on many items, and can be
particularly bad with refrigeration and air-conditioning units if the
piston stopped previously at just before TDC.  This is the reason you
can sometimes see lights momentarily "dip" when these things start up
depending on the house wiring.





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and get hot (OK, the soldering station is meant to, but electric motors
aren't). I suspect that running such things off a modified sine-wave
inverter can represent a fire risk.

Sylvia.

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You were right, it is working OK. Thanks!

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