HOW CIRCUIT BREAKER RATING CALCULATED?WHAT ARE THE
PARAMETERS CONSIDERED?

Answer Posted / r p payasi

kVA rating=Sqrt(3)*KV*Fault current(max)

so required is
1.Voltage of line
2.max fult current

Is This Answer Correct ?    14 Yes 3 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

What is the reason of polyphase induction motor tripping suddenly on high current during running at 70% laod? Motor IR , winding resistance & inductance balance. Motor no load current is balance and ok as per mgfr. data.

1942


1.how many types of relays? 2.difference between ATS& STS?

1643


How we calculat the NGR of 3phase Generator, Our generation voltage 11KV

2870


block diagram of 2 ups system connected in hot stand by mode?

7479


What kind of socket shall be provided for window type air conditioner with cooling capacity upto 18000 BTU/hr

639






Explain in brief description about the operation of DG sets.

1868


at work we have a 3 phase motor but on testing one phase isnt getting a reading. it runs 24 hours a day all week. stops and starts well no noise or heating. the phase isnt down to earth.is it just a bad meter reading or not? phases one and three came up with a resistance reading of 0.4 but phase 2 couldnt get anything shows up as open circuit.

1170


i am an maintenance engineer. one distribution board have 5 feeder. recently its ELR trips frequently, but it take some times after trip( 10min,20min..)but 3 feeder no load. two feeder only loaded. i checked one feeder IR value all values are above 50Mohm.but B phase to Earth is only 9Mohm.any problem about low value

1407


What are the basic component of a cro?

744


why we use the 100% and 95% stator earth fault protection for the synchronus generator ?

1813


How generator NPS(NEGATIVE PHASE SEQUENCE TEST)TEST WAS DONE? PROCEDURE WITH DETAILS?

1711


Can i replace Earth leakage relay to the faulty Earth Faulty Relay

1035


I have a CT meter with ratio 60/5. The meter reading of previous month was 3290.49 and that of current month was 3797.26. How many chargeable units as per normal meter should be my reading.

962


What is NGR . What is the purpose of 10 sec ,60 sec rating of NGR.

1238


how does ELR works? explain

2140