Answer / nilesh

Efficiency = Output Power/Input Power

Answer / swapnil

1]first of all to calculate output power of rectifier by
using formula P=VI*PF
2]CALCULATE THE INPUT POWER BY USING SAME FORMULA.
3]CALCULATE EFFICIENCY BY USING FORMULA

EFFICIENCY=OP/INPUT*100

Answer / stanley electrician

Dear Mr.swapnil,

you have given the formula as P=VI*PF for both
input and output.
You should remember that the pf is not considered in the
DC (output of rectifier).

MY PROBLEM IS, OUTPUT POWER OF THE RECTIFIER IS GREATER
THAN INPUT. SO THE EFFICIENCY IS MORE THAN 100%. But the
efficiency must be with in 100%.

Any way thank you for your answer.

Answer / vishvesh bhatt

here, we are getting efficiency more than 287 % therefore
pls check the numbers in the example given...

Answer / vinayak

i) input = 240 vac*5 a a.c.* 0.98 pf = 1176 watts
dc side output = 54 vdc * 62.6 a d.c =3380.4 watts
since eff. = o/p / i/p = 3380.4/1176 = 287.45 %
so it will be, instead of power losses , power producing
pl. check i ac & p.f. & o/p i dc , also 240 is i
phase or 3 phase ckt?

ii) input v ac 415 , a ac 525 ,say p.f 0.8 i/p power =
1.732*415*525*0.8=301887.6 watts
output vdc 92 , adc 2700 = 92*2700 = 248400 watts
eff. = o / i put = 248400/301887.6 = 82.28 %

Answer / sanjeev dixit

How can calculate the efficency of the rectifier, input
415V AC, Current 525 AMPS, oUTPUT IS 92 v dc, 2700 A.

Answer / maxim tellis

your given data is giving more output power than input power which is not at all possible. pls check the input and output current readings again.

Answer / shrinivas

As you are saying the input 240V, 5 Amps and the PF is

The input power becomes 1176 and for output of 54V and
62.6A...then putput power is 3380.4 therefore the Efficency
becomes (1176 / 3380.4) x 100 = 34.79%

Answer / azeeem

I have a rectifier with the following conditions. I wanted to calculate efficiency.

For AC Input:
Voltage on AC = 380
Power Factor= 0.80
Amps on Phase 1 = 9.17
Amps on Phase 2 = 9.50
Amps on Phase 3 = 15.70

For DC Output:
VDC= 2.39
ADC= 1260

Thanks.

Answer / sam

input p=v*i cos pi

=1176W
dc p=v*i

=3380.4

eff 34.89%

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