we have 3.5MVA-11/6KV transformer. how can we calculate earth fault current and NGR calculation?

1491

Define what is the function of anti-pumping in circuit breaker?

1273

How cable from Kit-Kat to main switch, from starter to motor are designed?

2066

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.

1977

I am getting above 60 V as open delta voltage against single phase unit ICT at tertiary delta formed and ICT getting trippped on NDR. ICT tested and found in order. PTs provided on tertiary are tested and in order. what may be the reason?

1822

is the value of inductance depends upon the evalue of thitha in doubly excited machine?

1834

Hi everyone, I'm Lachuu, recently joined automation company as PLC Engineer. I have certain basic question, I request all big gurus and seniors to answer these question. Because this will be very helpful to me as well starters like me. How to design a control circuit (ex: pick & place - my current project) Yamaha robot PxYx series controller RCX222, using 6 cylinder double acting, plc keyence kv p16r 2 expansion unit for input and output each. How to select panel terminal mcb elcb powersupply. My main concern in some projects how to select dc power supply, mcb rcb(I came across dif bt b c d curves, but stil confusing, pls help me :-(. I would really appreciate all who are going respond to this question.

1919

WRITEDOWN FEW RELY CODES

2230

what is the purpose of bypass mode in energy lighting transformer?

2453

what is transient enclosure vltage , very fast transients, very fast transient over voltages

2106

Explain the fundamental difference between emf (electro motive force) and pd (potential difference) ?

1105

why the neutral line is not giving shock to us if we touch it ?

1728

What is the alternate solution for testing of polarity by using polarity tester while its milli ammeter does not works?

1994

How can claculate to attain the desired PF in the line ( HOW Much KVAR is required ) Pls Give the formula? Equate Petrochemical 0 1 how to calculate sizing of NGTR (Transformer rating,Loading resistor value and Current rating of resistor) and what is the X/R ratio. Details : 11kV,Capacitance 1.73532 micro farads,40kA for 1sec. 0 1 What will happened. if we feed 3phase supplay to the stater with out insert the rotor. How much current will flow through the stater winnding? Equate Petrochemical 0 1 What is required of exietation to the alternater. 0 1 why star point of HT motor not earthed? Equate Petrochemical 0 1 Why we are getting low voltage in star connection? Equate Petrochemical 0 2 What's ND relay & it's functions? Equate Petrochemical 0 2 How instantanious short circuit current is calculated? its formula? Equate Petrochemical 0 2 What is servo Motor? What's the advantages of this motor over Induction motor? Equate Petrochemical 0 2 What is core CT & it's function? Equate Petrochemical 0 3 what is meant by star/delta voltages as 440/220 in a 3 phase induction motor, and why it should be connected on STAR IN 3 PHASE SUPPLY L & T 0 4 What is required of exietation to the alternater. KNB 1 23 what is the design voltage for 6.6KV 2000 KVAR HT capacitor? Consultancy 0 3 Pls explain about vfd control?Where it is used, Give some example? siemens 1 22 Please explain me abt PQ diagaram in the power sector. 0 9

2111

In EB metering we face problem kva jump even in no load condition.can any one help to control this

1797