10kva problem

how do i calculate 10kva so i can work this question out ?

a 3 phase 10kva transformer has a pf=0.9.calculate the line current for the transformer.

will i use sqaure root to work this question out ? are just x them all togeather?

I don't think you have enough information there, what voltage are you expected to use and is it star or delta configeration?

i take it is 50hz.i worded the question the way it is on the sheet.

i take it is 50hz.i worded the question the way it is on the sheet.

Click to expand...

frequency has nothing to do with this question - as above, we need more information to give you an answer

but at a quick guess, id say answer may be 13A?

16amps on the answer sheet.tryed some other questions and they did`nt work out but where close to what i got.

web site was swindon massive

16amps on the answer sheet.tryed some other questions and they did`nt work out but where close to what i got.web site was swindon massive

Click to expand...

really need more info on this. even assuming PF of 1, i get 14.45A

BUT: if it was 10KW and not 10 KVA, i get 16A

so working on that

10/0.9 = 11.11KVA

......................................kVA X 1,000

Three-phase amps = -----------------------------------------

........................................ 1.732 X Line to Line voltage

so 11.11x1000 / 1.732 x 400

= 16A per phase

or, the even easier way

KVA / 0.692 = A per phase

so 11.11 / 0.692 = 16A

(the 0.692 is the 1000, 1.73 and 400 all into one number)

or at least i think this is right

P = √3 x VI x pf

V and I being line values

I = P / (√3 x V x pf)

Getting an answer of 16.04A

Was beaten by andy

sorry, still don't see how you can calculate the current from the power with no voltage?

sorry, still don't see how you can calculate the current from the power with no voltage?

Click to expand...

hence i assumed 400V, obviously this would need to be checked against question. he did say 3 phase

mickey-c could you show me how you got 16.04 I = P / (√3 x V x pf)

(√3 x V x pf) pf 0.9 what did you use for v

what did you use for v

Click to expand...

400. but you will need to check question and use value in there

All I would say is

NICE