Answer / chintan patel

It can be different for DC , 1phase AC , 3 phase AC , systems,

Lets calculate for all ,

1 ) For DC ( you have not mentioned Voltage but considering 230 V )

100 kw means 100000 watt

formula for DC power p= vi

100000= 230xi

i=100000/230= 434 amp

we always use current rating of the mccb is 1.5 times of full load current so we can use 434x1.5= 652 amp.
( if system is not running on full load select 630 Amp MCCB, if its on full load select 800A )


2 ) For 1phase AC,

Power: P = V I cos phi ( cos phi is power factor is not known assume 0.8 )

100000 W = 230 x I x 0.8
I = 543 Amp

we always use current rating of the mccb is 1.5 times of
full load current.
mccb required 543 Amp X 1.5 = 815 Amp
select 800 Amp MCCB

3)

If load is 3 phase AC ,

Power P = sqrt(3) x V x I x cos phi

100000 w = 1.73 x 415 x I x 0.8
I = 174

we always use current rating of the mccb is 1.5 times of
full load current.
mccb required 174 Amp X 1.5 = 261 Amp

( if system is not running on full load select 250 Amp MCCB,
if its on full load select 315 A )

Answer / kalyan sharma

for 100 kw we will use 3 phase supply inplace of single
phase.

use formula p= 1.732 vi cosphi

100= 1.732*0.415*0.8*I

I = 174 amp

we always use current rating of the mccb is 1.5 times of
full load current so we can use 250 AMPs MCCB.3P/4P.

Answer / rajat

for 100 kw means 100000watt

use formula p= vi

100000= 230xi

i=100000/230= 430 amp

we always use current rating of the mccb is 1.5 times of full load current so we can use 430x1.5= 645 amp

Answer / r g walia

for 100kw load required 630 amp mccb will be used.

Answer / siddhart jha

mccb of 250 A/440V MUST BE USED FOR THAT.

What is the minimum IR value of HT/ LT cable? Pls post separetely!!!!!

0 Answers   Bhel,

---

In a star-star connected h.t transformer why we use NGR on the secondary (l.t)side.

3 Answers   Star, TATA,

---

how to get electrical supervisour certificate in gujarat

0 Answers  

---

Can somebody tell me the type and amp of transformer used to implement 600VA UPS? Thanks in advance.

1 Answers  

---

Why dont we get shock while testing for voltage with a line tester? How the bulb inside the tester glows while testing with tester coz we are totaly isolated from earth or we are not giving close path for the current to flow?

3 Answers  

---

---

what are the advantages and disadvantages of speed control of 3 phase induction motor by varying frequency explain with drawing

0 Answers   ABB, Genpect,

---

what is specific gravity of a battery if specific gravity increase/decrease,what will happen to the voltage/current of the battery

5 Answers   NTPC,

---

As per the theory current doesn’t flows in Neutral, but practically it is not applicable, explain why?

2 Answers  

---

What is the criteria for selecting the voltage classes of an AC Induction Motor.The KW rating above/below which ht/lt selection is made may be provided in details.

0 Answers   DAE,

---

WHAT HAPPEN IF TRANSFORMER HAS GIVEN SQUARE WAVE SUPPLY

3 Answers   APTransco, NTPC,

---

i need online ups battery calculater

1 Answers  

---

how we will deside the high voltage value

0 Answers  

---