how is the testing of an REF relay? what are the test REF circuit having?

0 Answers   Siemens,

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what is meant by phase &line voltage, how its differ from each other ?

5 Answers  

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If the secondary winding will be open in current transformer, how to damage the insulators

2 Answers   TPDDL,

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why ct ratio always rated 5.

1 Answers  

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need help, please can someone tell me how can i calculate the main breaker and branches breakers to distribution panels (MDB) depending on the load ampere .. i really need it but can't find any site >>

3 Answers  

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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.

0 Answers  

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how to calculate the Neutral transformer impedance?

0 Answers   Schneider,

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Rules and standards of electrical control wiring ?

0 Answers  

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How will be the single line diagram of series trip HT breaker? how it works?

0 Answers   HAL,

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Can you explain about TEE protection scheme?

0 Answers   Voltech,

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Why we are use dol starter up to 10 hp

0 Answers  

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Hi I'm doing my MBA(3rd semester).I applied for the post of ET conducted by BHEL the last year.I cleared the written and lost in personal interview.Again I wrote the exam this time and cleared the written n yet to take the personal interview.Shall I disclose in the interview about my studies.What shall i say if they ask about my change from studies to job

0 Answers   Bhel,

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