C
Chirrp
- Jan 1, 1970
- 0
Hi all,
we have a 5000VA UPS from APC, 5 years old (incl.batteries) which still
holds for various minutes at full load so we are keeping it. Downstream
from that one we have about 8 servers which load the UPS at about 80%.
The UPS is connected to a 16A line (220V) with a C charachteristic
curve. Normally the whole thing draws about 10.5A from there.
When we have a blackout and then the electricity comes back, the 16A
breaker trips, then after a few minutes the UPS batteries are flat and
the whole thing goes down.
I have tried pulling up the breaker when the batteries were totally
flat, and it would stay up for about 3.5 seconds (this is approximate
because I didn't really measure that with a stop-watch), then broke
again. I waited 10 seconds then I pulled it up again and that time it
stayed up. Reports from my colleagues are similar.
Now looking at the C charachteristics curve for the breakers,
(it is the one at the bottom of page 2, isn't it:
http://www.altechcorp.com/PDFS/CBC.PDF )
tripping after 3.5 seconds would mean that the UPS was drawing between
2.2 and 6 times the rated current (16A)! That's quite a lot of amperes!
Especially considering that after this transient, the UPS draws just
about 11.5A while powering the servers and simultaneously recharging.
Do you have a reasonable explanation for what is happening here?
It seems there is like a very large capacity loading...
Might this be a thing like "memory effect" of the old batteries which we
have in the UPS?
Unfortunately our panelmount voltmeter measures a moving average so is
not reactive enough to let us see how many amperes we are drawing in
those 3.5 seconds.
Thank you
we have a 5000VA UPS from APC, 5 years old (incl.batteries) which still
holds for various minutes at full load so we are keeping it. Downstream
from that one we have about 8 servers which load the UPS at about 80%.
The UPS is connected to a 16A line (220V) with a C charachteristic
curve. Normally the whole thing draws about 10.5A from there.
When we have a blackout and then the electricity comes back, the 16A
breaker trips, then after a few minutes the UPS batteries are flat and
the whole thing goes down.
I have tried pulling up the breaker when the batteries were totally
flat, and it would stay up for about 3.5 seconds (this is approximate
because I didn't really measure that with a stop-watch), then broke
again. I waited 10 seconds then I pulled it up again and that time it
stayed up. Reports from my colleagues are similar.
Now looking at the C charachteristics curve for the breakers,
(it is the one at the bottom of page 2, isn't it:
http://www.altechcorp.com/PDFS/CBC.PDF )
tripping after 3.5 seconds would mean that the UPS was drawing between
2.2 and 6 times the rated current (16A)! That's quite a lot of amperes!
Especially considering that after this transient, the UPS draws just
about 11.5A while powering the servers and simultaneously recharging.
Do you have a reasonable explanation for what is happening here?
It seems there is like a very large capacity loading...
Might this be a thing like "memory effect" of the old batteries which we
have in the UPS?
Unfortunately our panelmount voltmeter measures a moving average so is
not reactive enough to let us see how many amperes we are drawing in
those 3.5 seconds.
Thank you