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Correct Generator for APC Smart UPS 1500 series, in data center

Hello,

I am working on setting up a small data center and need to figure out
a good standby generator that will work with the current APC Smart-UPS
1500 series Battery backups.
I am looking for a unit that works on natural gas and has a transfer
switch. I will be connecting 12 to 18 of these UPS to the generator.

Does anyone have some good suggestions or leads that can help me out
with this issue. I am even interested in whatever you do "do not" take
this route information as well.

I have talked to APC and they recommended a RT Unit for the series of
UPS I will be using. Other then that they could not help me.

Thanks
0
wotan1953
Asked:
wotan1953
1 Solution
 
amaru21Commented:
I've done something similar to this with some APC SUA3000XL's.  I'm no electrician, so my solution was to talk to a local electrician!  They were able to install an electrical box in our server room that our APC units could plug into.  That box then ran to another box at the outside of the building that we could wire any kind of generator up to.  As for the specific generator, I guess it depends on how much power you plan to draw and how much of a runtime you need.
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CallandorCommented:
I have a neighbor with a fairly large house who installed a natural gas generator.  Take a look at some of the commercial units here: http://www.nextag.com/natural-gas-standby-generator/compare-html.  Generac and Briggs & Stratton are a couple of well-known suppliers.
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wotan1953Author Commented:
Okay I am still working on this. Here is where I am: seems as though .. out generator (while it has enough power) is single phase and the 1500's don't play well with single phase. So apparently, we can either buy a 50K 3 phase filtered LP generator ... which will work with the 1500's or we can upgrade to a better APC unit, and keep the old generator. But I am still waiting for our electricians to tell us that is the case ... for me I thought the whole phasing thing sounded sort of like an episode from Star Trek ;-)


Here is a good informational email I got on the subject:
########################################################################

If you are planning on using a "line interactive" ups you will need a =20=

VERY BIG generator.  Lets say that you use 15 of these APC1500 unit. =20
That is 22,500 VA. Take that and multiply it by 5 and you will get the =20=

size of generator that you need. Ex: in your case. 100Kva. A generator =20=

in that ballpark is $50-60k. Look at a UPS upgrade to a 3 phase unit =20
and you will pay for the new UPS with the lower cost of the generator.


Here is some 'tech' on the subject.

Generator Sizing guide

Passive (also referenced as standby or off-line) and Line-Interactive  =20=

Product is APC Smart-UPS
These technologies are most common for personal workstations and point =20=

of sale applications. They are typically single phase equipment with =20
size
ranges of 350 VA - 2000 VA for passive and 500 VA to 5000 VA for line-=20=

interactive.
Passive UPS=92s are the simplest type. Under normal conditions AC power =20=

passes straight through to the UPS load. When the input power supply
goes outside of specifications, the UPS transfers the load from input =20=

power to the internal DC to AC power inverter. Passive UPS=92s do not =20=

correct for
voltage or frequency deviations under =93normal=94 operation.
Line-interactive is similar to the passive technology except it has =20
circuitry that attempts to correct for standard voltage deviations. =20
Frequency deviations
under =93normal=94 power operation are not corrected.

Equipment Notes:
These devices tend to be electrically / harmonically very noisy. A =20
single small UPS is not a significant concern, but applications
with multiple UPS=92s can be problematic.
Passive UPS technology typically has normal tolerances of 10-25% on =20
voltage and 3 hertz on frequency. If the input source goes
outside of these tolerances, the UPS will switch onto the UPS battery =20=

source. Some line-interactive units may have frequency
tolerances factory set to .5 hertz. These units will need to have =20
their frequency tolerance increased to a minimum of 2 hertz.
Generator Sizing Recommendation:
Limit the total UPS loading to 15% - 20% of the generator capacity.

Double-Conversion product is APC Symmetra -
This technology is most common for critical load applications. Double-=20=

conversion UPS=92s constantly rectify AC to DC and then invert the DC =20=

back into
AC. This configuration results in an output that corrects for voltage =20=

and frequency deviations.
There are single and three phase models covering small through large =20
applications. Most UPS applications larger than 5000 VA use double =20
conversion
technology. This approach is also the preferred technology for =20
generator applications.
Equipment Notes:
Double-conversion UPS=92s that are single phase or unfiltered three =20
phase models tend to create a significant level of electrical/
harmonic noise. This is illustrated by harmonic current distortions =20
that are greater than 35%. When three phase models are
supplied with harmonic filters (current distortion less than 10%), =20
this concern is no longer an issue.
Generator Sizing Recommendation:
Single phase models: limit the total UPS loading to 25% of the =20
generator capacity.
Three phase models without filters (current distortion > 30%): limit =20
the UPS loading to 35% of the generator capacity.
Three phase models with filters (current distortion < 10%): limit the =20=

UPS loading to 80% of the generator capacity.

########################################################################


So thanks for everyones help and Amaru21 has it.

- wotan1953
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