UPS Systems

Ask the UPS manufacturer immediately.

kondaas

" Let us assume the following ideas:

• Inverter efficiency of UPS battery is 90% (the norm is somewhere between 90% and 98%)
• Battery end point voltage 1.67 (usually specified on the UPS itself, or in its manual)
• Environmental temperature 77F

Assuming that we know the following things about our UPS : one string of batteries, 30 each, UPS rating 40kW and 6 cells per unit, we can break down the calculations in three steps:

1.) Actual battery load for 40kW

40kW … 90% efficiency means an actual 44.4kW load

(you can calculate this by dividing the rating of the UPS by inverter efficiency - 40/0.9 = 44.4kW)

2.) Watts per Battery

44.4kw (previously calculated) will be divided by the number of batteries we have available, and the result will lead to 1481 watts per battery.

(you can calculate this using the equation: 44.4Kw/30 = 1481W)

3.) Watts per each Cell

Giving the necessary data we will deduct that each cell needs 247W.

(calculate this using the equation: 1481W / 6 (the number of cells per unit) = 247 watts per each cell)

Now we can easily estimate the run-time of your UPS battery back up system. Giving the fact that we know that each batter has about 247W per each cell, and we have a battery end point voltage of 1.67V your run time should be somewhere between 45 minutes and 60 minutes.

http://www.backuphowto.info/how-calculate-ups-battery-backup

Where does the 40kW come from? OP said 3 kva.

It's an example, presented so the OP can solve the problem on his or her own....

OK ta

How many phases does this UPS provide?

When you say connecting "systems" do you mean UPS' or something like computer systems?

Are you asking what load you can place on a 3 kVA UPS? How long the batteries will last at full load? What power factor are you looking at currently? Future?

How are the battery cell(s) configured? 6VDC, 12VDC, 24VDC, or 32VDC batteries/cells?

Maybe just providing the manufacturer and model would be easiest.

single phase UPS .3 KVA UPS

13 Desktop computers ,intercom system & ethernet switch port 64*2.

maintained power factor 0.71.

12v,40 ah of 8 battries connected in series total 110v.

efficiency 75 %

can i connect extra 2 sytems to UPS will it create problem.

.3 kVA (Point Three?) That's a really tiny UPS. How do you have that much equipment physically plugged into one UPS with such a small capability?

That would explain the low power factor and efficiency. You need a bigger UPS or multiple UPS' of that size.

My desktop UPS at work is 1.3 kVA.