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.

difference between power surge and switching transient

0 Answers  

---

is there any concept of armature reaction in Induction motor?

4 Answers  

---

hii.i am a B.TECH(EEE) graduate.i want 2 know wat type of qusns r asked in sbi clerk interview 2 candidates like me??kindly post answers ASAP..

1 Answers  

---

How can we get d.c series motor characteristics by using a.c induction motor?

1 Answers   IIT,

---

why +24 v and -48 v give to BTS? If -48v protect from surge then why we not use -24 v?

0 Answers  

---

What size cable (based on voltage drop) is required to supply a 40 A three phase boiler if the wiring system is 75V single insulated cables installed in non-metallic rigid conduit 56m from the main switchboard? Voltage drop in the consumer's mains is 8V.

0 Answers  

---

what the good value of earth resistance test

3 Answers  

---

i am going to give the JSEB,RANCHI exam for power plant,so i need some samples of papers related to that,so please send me these papers by my mail id.

0 Answers  

---

what is the basis for selection of Protection CT class ? How anyone can decide whether to go for 5P10 or 5P20 ?

3 Answers  

---

what is the difference in between short time and continuous rating?

1 Answers  

---

what is the function of choke and starter in a tube light??

2 Answers  

---

As we know,charged clouds(from which lightning stroke initiates)may be charged with either +ve charge or -ve charge. Now say one cluster of cloude is fully charged with +ve charge & another cluster is fully charged with -ve charge. In the sky these two cluster of charged clouds have come in such a distance that, if they come clouser by some few yeards then the lightning discharge will take place between these two cluster of clouds. Under such a situation an Aircraft came inbetween. what happend??

5 Answers  

---