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

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When i went to a interview the interviewer ask me a question for that i cant able to answer him if anyone knows answer me How will you design a capacitor bank for a plant? if my p.f is 0.6 i have to improve it to 0.9 or 1 what kind of steps i have to do? and is there any formula for calculating this?

2 Answers  

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if the stetor speed (N S) increase by 20% then the rotor speed will be increased by 20% is it true. ?

4 Answers  

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When connecting a loaded powerplant to the Huge grid,what are the factors to be considered and how the VAR flow will affect the system?

1 Answers  

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Dear friends, i would like to know that what is the exact function of 'exciter winding' & 'aux winding' in Alternator?

0 Answers   NTPC,

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When a 25kV line touches the train, will passenger get shock?

3 Answers  

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how to test generator protection rotor earth fault relay and locked rotor test?

1 Answers  

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Explain What will happen when direction of field current is changed (i.e, field excitation is reversed) in the following machines? 1) Alternator 2) Synchronous Motor 3) D.C Generator ( Shunt or Seies ) 4) D.C Motor ( Shunt or Seies )

3 Answers   NTPC, Transco,

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How much pf maintan in dg set in 6o% load,when Dg runnig Neutaal Earthing removed what happen.

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need to make a report. Need to choose a 3phase induction motor. Load conditions motor will operate in : Maximum Load: 30 Kw Speed: 2950 rpm Ambient temp: 20 cent Supply voltage: 440V Frequency: 50Hz need to look for the safety factor when choosing the motor, went through catalouge found a few, but dont know how to choose the safety factor allowing an extra load something above 30 KW to avoid any harm.

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what is the use of surge suppresser in 33 KV incoming panel. where it must be installed,inseries with incoming cable surge suppresser must be at incoming of the breaker are outgoing of the breaker

1 Answers   Siemens,

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We have three phase dg of 12kva rating.If the load of each phase is not constant.That means one phase drowning more load than remaining two phase..Then what will happen to dg?

1 Answers   Indotech,

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