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.

why voltage form factor of PT are increase , when it is ecpected heigher spikes in system. how it is calculated.

0 Answers   HAL,

---

what will happen at secondary side of transformer if i increase voltage at primary side?while V1*I1=V2*I2 will secondary voltage or current increase?

2 Answers  

---

what is the IPC ? & what the uses ?

0 Answers   Bhel,

---

How to reduce current flowing in neutral due to unbalanced load conditions in a three phase system.

1 Answers   IOCL, wbsedcl,

---

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

0 Answers  

---

what will happen when two dc motors are connected to each other and anyone of them rotated?

1 Answers  

---

Dear all, I want to use Induction motor to open and close a 1 ton door. How much power do I need. Thanks

0 Answers  

---

How can we save theft of wire after finishing of wiring work, plz suggest another answer other than security or supervisor's work?

1 Answers  

---

What is mathematical model of a control system?

0 Answers  

---

How to do cable earhing? whether by grounding Armour to ground or by running extra G.I wire along with cable? which one is preferred mostly amoung them? If the second one is more preferable how many GI wires to be run along with cable (1 or 2)?

0 Answers   HAL,

---

Why do we need a separate control desk & PLC control panel in Boiler plant or coal handling plant? Can we provide cost effective Control desk cum PLC panel. Is there is an specific need for control desk.. kindly advice.

0 Answers  

---

what happen to the voltage and current in all phases when an earth fault occur in a phase in three phase three wire system(delta connected)...

1 Answers  

---