Answer Posted / subash

uncontrolled rectifiers and variable resistance.

1. A 380 / 220 V r.m.s. 3-phase 4-wire circuit carries loads of 8 + j8.1 ohm; 4 + j4.1 ohm; and 2 +j2.1 ohmin the three phases respectively. The length of the circuit is 100 m, and the resistivity of the phase conductors is 0.0005 Ω/m. The neutral conductor is of the same size as the phase conductors. a) Select a reference angle 0for the first phase. Then write down the three phase voltages in both polar format and complex number format. b) Make appropriate assumptions, and take temperature effects on resistance is insignificant. Calculate the currents in the three phases. (Note: Determine conductor resistance, and apply Kirchhoff’s Voltage Law) Based on the result, suggest a main switch rating for the circuit. c) Show your preferred direction of neutral current in a diagram, and then determine its value. (Note: Apply superposition principle, and Kirchhoff’s Current Law) Use its magnitude to show that in this circuit, the unbalanced load may increase the voltage drop in some of the phases. (Note: Also observe the common volt drip in neutral) State your assumptions, if there are any. d) Suddenly the neutral wire of the circuit is broken. Estimate the new currents in the first phase, i.e. Phase L1. State your assumptions, if there are any.

2029

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what is the path of thunderlightening? once both a buffalo and a person were standing 5m apart but lightening hit and killed buffalo not person?

2870

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A parallel flow heat exchanger will perform better than a counter flow heat exchanger. State if the statement is true or false.

1251

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explanation of mesh bus bars

2160

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which phase is preferred for connecting 1 phase vt used for synchronizing OHL? WHY?

2043

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in ACB breaker requireding 3200Amps. buscoupler getting OFF mode and again it reset and getting normal position give me a required answer?

2334

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Can any one know what are the symbols at the down (below) the analog ammeter??? there are 4 symbols which are they ?????

1902

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what is the use of expulsition protective gap in 11Kv line.

2123

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how to commissioning the genset with amf panel?

2398

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1. Can a 12v DC choke operate a 60v/12w PL lamp ? 2. Can a 230v ballast fire / operate a 60v/12w PL lamps.

2183

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What about electrical Units. discrive in detail

2086

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Do you know what is dry-out test in x'mer

2645

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give me a clear defination of inductance,and how can u calculate inductance of a motor

2798

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What is meant by Load Encroachment in OHL Feeder Protection?

3627

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When we have earthing mesh or underground earthing network in industrial plants, weather we have NT-S or NT-C-S kind of earthing system, so eventually weather we must use 4 or 5 wire in 400 volt level (For example 3×150+70 mm2 or 5×150 mm2) in this connection I would like to know exactly the paragraph of IEC or IEEE number

2165

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