Answer Posted / sudhir

for 4 phase system ,phase difference b/w phase 0,90,180,270
deg.at every instant 0deg phase cancil by 180 deg phase,and
90deg phase cancil with 270 deg phase . and two conductor
work as phase and two for return path so it work as two
circuits of two phase supply and there are lot of advantages
of three phase supply over two phase supply.if we need of
two phases then it is simply generated by three phase.
and three phase system is symmetrical(line voltage or
current in magnitude between any two phases is equal to
other two phases in balance condition ) but 5 phase circuit
is not symmetrical.so calculation and operation is difficult.
as we increases the phases the fluctuation of torque in case
of polyphase induction motor is reduses.so 6-phase motor is
bater then 5-phases motor and 6 phase supply
simply can obtains by 3 phase supply so why we generate 5 phase
supply.

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4149

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why we use ac supply as 415 volts instead of 415 v why we cant apply 230 v for dc

2395

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what is apparent poewr, reactive power, & active power?

2331

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What is clock position of Transformer?what are the clock positions are there?and what is different of them?

3131

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Wt is the function of reactive power? How it generates & consume though resultant is zero?

1879

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Draw a 230kv two-bus bar system showing the following. 1.Two generators (150MW) each connected through one 15.75/230KV transformers 2. 1 outgoing lines 3. Two 230/130 KV transformers 4. BUS PT's 5. CT

2581

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what is meant by 2 within a star in a voltmeter dial?

2051

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What is the role of feedback in a closed loop control system?

1072

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can you any one give exact mathematical relation between AC current and DC current?

1990

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please describe the Transformer setting, Motor setting, I/C setting, Tie setting

1765

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ii) A shunt motor supplied at 230V, runs at 900 rpm when the current is 30A. The resistance of the armature is 0.4 ohms. Calculate the resistance required in series with the armature to reduce the speed to 600 rpm, assuming that the armature current is then 20A. [12]

2337

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please send me RRB electrical engineer previous year questions for Sr. Section Engineer

1938

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Is there a standard depth of gravel fill in Substation Switchyard? Please give a design/drawing. Thank you.

5392

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I'm generating a pulse of 3V with frequency 80Hz (12.5ms time period) and pulse duration 0.125ms and feeding it to a transformer since i want the pulse to get amplified around 60V. At the output amplification s happening but the pulse is changed to a spike, can you tell me what could be the reason? (an ordinary transformer 220V-12V stepdown transformer is reverse connected ie. now it is 12V-220V stepup and voltage amplification happens)

1878

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Define the overload capacity of the motor?

2034

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