Answer / kuzhali

ups back up time=(AH rating*volt*power factor)/total load

Answer / velmurugan, so/d, barcf, kalpa

Consider the 2 KVA online UPS.
specifications are as follows: output voltage: 230V, Pf:
0.8, Load is 1600W. DC bus voltage is 96V.

Now Total output is = 2000 VA
PF of the load is = 0.8
There fore output in watts = 2000x0.8= 1600W.
Efficiency of the inverter is 80% therefore power input to
the inverter will be = 1600/0.8= 2000W
DC current of the inverter section= Watts / Voltage
Consider the fully charged voltage = 13.5X8=108V
The DC bus voltage
up to which the battery can deliver= 10.5x8=84 Volts.

therefore maximum current drawn by the inverter when battery
is in line = 2000/84=23.8A

Now consider the backup required for the load, i.e 1 hour
back up is required to safe shutdown loads when power supply
is not available.

Consider a class 10 type of battery where it has a
efficiency of 90%, 300Ah battery.

the effective AH available for the load is 300x0.9=270AH.
For 1 hour duration the discharge current will be 27.0A
which is higher than the required value of 23.5A.

There fore for 2 KVA online UPS having the load of 1600W
with 0.8 pf load, it requires 300AH of 8 nos of battery for
1 hour backup.

what is package substation.how many types they have

0 Answers   ABC,

---

50 electric bulbs are connected across supply of 220 volts. After one bulb is fused remaining 49 bulbs are again connected to same supply. which case will have more illumination & WHY????????

5 Answers   KJ,

---

How does MCB operate without relay..?

10 Answers   Toyota,

---

The following equipment are installed ia a plant 1. 110KW Induction motor 4 Nos 2. 30 HP motor 3 Nos 3 15 HP Motor 3 Nos 4 7.5 HP motor 4 Nos what is total load of plant if one of each is stand by.

3 Answers   Blue Star,

---

sir pls send the je exam - 2008 and other model question papers..

0 Answers  

---

---

Among the following Which is vector quantity? a. Flux b. permitivity c. flux density d. magnetic intensity

2 Answers  

---

it is difficult to interrupt a capacitive current because (a)it has a leading power factor (b)current magnitude is very small (c)the restriking voltage can be high (d)stored energy in the capacitor is high

2 Answers   DGVCL Dakshin Gujarat Vij Company, MGVCL, UGVCL Uttar Gujarat Vij Company Ltd,

---

yesterday i am using my laptop by plugging power supply also battery was working properly after while i unplugged AC power source ,using my battery i played car game (use much power) after that the battery finished the charge and it closed my PC. after that my battery not charge (when unplug automatically PC will turn off)

1 Answers   HPCL,

---

For having nonavailablity of 10 Amps fuse, a lineman replace the same with 5Amps two strand, Do he correct ?

4 Answers  

---

what is harmonics?

1 Answers   powercom,

---

what is current

8 Answers   NTPC,

---

explain maximum demand factor

1 Answers   Sterling,

---