Engineering Interview Questions
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How to calculate voltage drop in copper and aluminium cable? I have laid 240Sq.mm Aluminium cable for the length of 600 Mtrs in 1 Mtrs underground. Normal load is 150A. Transformer is 630KVA, 6.KV/433V. But, I am getting only 395 Volts when load. How to calculate voltage drop and what is the permissible voltge drop for this circuit?

1 1747

11kv/433v delta/star distribution transformer primary side full load Ht current is 83.33A in , but input side VCB rating 800A.why?

1201

In apron feeder how TPH is calculated?

Lafarge,

1174

a)In a 3-phase 4-wire circuit, a circuit breaker is selected to protect the circuit whose highest fault level is 6.6 MVA. Determine the required minimum breaking capacity in kA. (Note: Covert 3-phase power in terms of kA to find answer.) b)Using the below, determine the required minimum making capacity in kA as a “peak value”. Rate breaking capacity (Icn) ka: Icn<= 1.5 Factor = 1.41 1.5

1173

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.

1473

Gidc technical que paper

GIDC,

1246

Why capacitor bank ratting Kvar?

1 1903

Question 82 - (a) The Hyperion sewage plant in Los Angeles burns 8 million cubic feet of natural gas per day to generate power in United States of America. If 1 metre = 3.28084 feet, then how many cubic metres of such gas is burnt per hour? (b) A reservoir of natural gas produces 50 mole % methane and 50 mole % ethane. At zero degree Celsius and one atmosphere, the density of methane gas is 0.716 g / L and the density of ethane gas is 1.3562 mg / (cubic cm). The molar mass of methane is 16.04 g / mol and molar mass of ethane is 30.07 g / mol. (i) Find the mass % of methane and ethane in the natural gas. (ii) Find the average density of the natural gas mixture in the reservoir at zero degree Celsius and one atmosphere, by assuming that the gases are ideal where final volume of the gas mixture is the sum of volume of the individual gases at constant temperature and pressure. (iii) Find the average density of the natural gas mixture in the reservoir at zero degree Celsius and one atmosphere, by assuming that the final mass of the gas mixture is the sum of mass of the individual gases. Assume the gases are ideal where mole % = volume % at constant pressure and temperature.

1 1901

How to define Kirchhoff current law and voltage law along with simply examples.

1206

Stringer How many cm goes to landind

ACC,

1193

Rate analysis for construction of a solid block masonary of size 400x200x200 in C.M.1:5 in superstructure .Compressive strength 5.00 N/Sq.mm Confirming to IS: 12894:1990, with necessary scaffolding, raking of joints and pointing the same. I require rate per Cum.

Alagar Builders,

1979

MASS TRANSFER - EXAMPLE 4.1 : A concentric, counter-current heat exchanger is used to cool lubricating oil. Water is used as the coolant. The mass flow rate of oil into the heat exchanger is 0.1 kg / s = FO. For oil, the inlet temperature TIO = 100 degree Celsius and the outlet temperature TOO = 55 degree Celsius. For water, the inlet temperature TIW = 35 degree Celsius and the outlet temperature TOW = 42 degree Celsius. What is the mass flow rate of water in kg / s, FW needed to maintain these operating conditions? Constant for heat capacity of oil is CO = 2131 J /(kg K) and for water is CW = 4178 J /(kg K). Use the equation (FO)(CO)(TIO ?TOO) = (FW)(CW)(TOW ?TIW).

1 1718

MASS TRANSFER - EXAMPLE 4.2 : In a non-dilute absorber, graphical method is used to represent the process. In an X - Y coordinate system, X-axis represents mole of carbon dioxide / mole of water and Y axis represents mole of carbon dioxide / mole of nitrogen. The inlet gas stream consists of 8 mol % of carbon dioxide in nitrogen. (a) Find the S / G minimum as a slope that goes through the point (0, 0.0304) and (0.0000488, 0.086957). (b) Find the actual slope of operating line when it is 1.5 times the S / G minimum! (c) Find the value of x for inlet gas stream when y = 1640 x, y is mole fraction of carbon dioxide in nitrogen.

1 1684

Two way slab, curtailment provided in both side in longside and short side. which side curtailment provided in one way slab?

IBA,

1 2434

Merz-Price circulating current principles is more suitable for

Student,

1 4774


Un-Answered Questions { Engineering }

sir, i have completed engineering diploma in electronics and now got the call letter for written exam for the post "junior engineer" from rrb chennai. could you help me about the model and type of questions that i should prepair?

1723


How video signals are produced?

1423


What is rolling stock

1874


How to calculate the cement and fine aggregate requirement for solid block masonry works in terms of Sqm. 1. 400x200x200mm 2. 400x200x100mm 3. 600x200x100mm 4. 600x200x200mm I need the answer for 1 Sqm of solid block works.

2175


1)What is the total volume of aggregates required for 1cu.mtr.solid hard concrete? 2)What is total mass of wet concrte and dry concrete after 28 days of M25? 3) Is 28 days strength is the final strength of concrete or it gets increasing as the time period increses.? 4)What is the volumetric proportion of concrete grade of M25.M30,M35,M40

2248






DEFINE BREAKING CAPACITY OF BUSBAR & HOW IT IS CALCULATED?

4772


"TRANSFORMER MODELING AND ANALYSIS" MEANS WHAT AND WHICH TOPICS U READ IN THIS

1403


what is meant by surge? what we called for high currents?

1479


Can have i call constructor in interface?

1380


HOw much % of premium on DSR-2013 currently

1523


The knee point of a current transformer is normally unique and known.So why in the nameplate of a CT they put the minimum value like this Vk> 400v.

921


How the priming can be implemented in a centrifugal pump?

639


How to arrive dry volume of concrete (1.52 to 1.57) ?

1892


If we need4× 50mm sq cable but it's not available so we can pull 4×25mm sq 2cables

887


How many energy meters can be connected on a 15VA Voltage transformer. please send a calculation sheet.

1495