what will happen if phases are not shorted with neutral in transformer impedance test? and if neutral is not connected with ground?

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What is Tan Delta Test

1 Answers   Power Grid,

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I HAVE A 50A MCCB AS PER DESIGN LINE WIRE CONNECT UPWORD SIDE AND LOAD IS CONNECTED TO DOWNWARD SIDE TO THE MCCB.IF NOW ANY ONE CHANGE SUPPLY & LOAD(WISEVERSA) WHAT HAPPENS ? DOES MCCB OPERATION OR WORKING FUNCTION NORMAL IF YES THAN WHY THERE ARE MARKED LINE & LOAD ON MCCB.

0 Answers   HCL, TCS,

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why the transformer ratings in kva or mva?

4 Answers  

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Different types of relay fault which phase sequence??

0 Answers  

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assume we are put both df/dt and vector surge relay in same bus the df/dt relay setting is +5 hz an -5HZ. we want operat the vector surge relay before the df/dt how i calculate the setting of the vector surge relay.

1 Answers  

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primery try cell?

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how calculated Transformer losses.

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how we select the mva rating of the circuit breakers?

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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.

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How to calculate the current rating of power cables ?

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if 6 earth pit value is 1.5 ohm then what should be the number of earth pit to make the value .8 ohm

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