Electronics and Electrical Engineering interview Question and Answers for fresh engineers (Part 3)

Electronics and Electrical Engineering interview Question and Answers for fresh engineers (Part 3)

In this topic we know about ,electric supply system,electric supply system classification and principle components,components are used for dc to ac convert or ac to dc convert

Question 10: What is electric supply system?

Answer 10:  Electric supply system: The process of transporting or conveyance of  electrical energy or power from a power station to the users premises (home, industry etc) is called as electric supply system.

Question 11:  What are the electric supply system classification and principle components?

Answer 11: The electric supply system can be classified into two types:

                   і)  AC or DC supplies system.

                   ii) Underground or Overhead Supply system.

In the electric supply system the 3 phase 3 wire system is used for AC energy generation and transmission. In the distribution system three phase four wires is used now a days. This system is now used all over the world.

In the underground system tunnels are used and in overhead system poles are used.

Question 12:  Which components are used for dc to ac convert or ac to dc convert? What is the operation range of these devices? What is present day’s trend for generation and transmission?

Answer 12:  The high voltage dc transmission is much better than the high voltage ac transmission. So, now the electrical engineers grow interest for transmission of dc in place of ac.

The use of Mercury arc rectifiers and thyratron gives opportunities of converting a.c into d.c and the conversion of dc to ac to the electrical engineers.

Figure: One line diagram for the high voltage dc transmission

In the given one line diagram the electrical power is generated as ac and stepped up to high voltage by the help of stepper transformer. Then this high voltage energy is transferred to the Mercury arc rectifiers, which change ac to dc. After that time this high voltage dc is passed through the thyratron, this thyratron convert dc to ac again. After that this high voltage is stepped down to low voltage in receiving transformer.

The operation range of such devices is up to 30MW at 400KV in one single unit.

The present trend is using ac for generation and distribution.  And the dc is used for high voltage transmission.

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Electronics and Electrical Engineering interview Question and Answers for fresh engineers (Part 2)

Electronics and Electrical Engineering interview Question and Answers for fresh engineers (Part 2)

In this topic we will find some question about transmission voltage, regulator difference, motor type of fans, unit of electrical energy

Question 6: What are the advantages of high transmission voltage? What are the limitations of the high transmission voltage?

Answer 6:  Advantage of high transmission voltage:

                  

1. It reduces the volume of conductor material.

                   2. It increases the transmission efficiency.

                   3. It decreases the line drop percentage.

       Limitations of high transmission voltage:

1.The insulation cost of the conductor increased.

2.The other terminal operators, switchgear and transformers cost is increasing.

Question 7:    Which is better between electrical rheostat regulator and electronic regulator for fans? Which is the basic component difference for them?

Answer 7: The electronic regulator is better then electrical rheostat regulator. In electronic regulator the power loss is very low. The electronic regulator only transfers the necessary power for the necessary speed of the fans. But in electrical rheostat regulator the power loss is same for every speed, so no power is saved.

The electronic regulator use TRIAC for speed control by varying the firing angle speed.

 The electrical rheostat regulator use control resistance, which is increased or decreased by the variation of speed.

Question 8: In our normal household fans (such as exhaust fan, pedestal fan, ceiling fan, table fan etc) which types of motor is used? What is the rotor type and starting type normally?

Answer 8:  In our normal household fans single phase induction motor is normally used.

The rotors are mostly squirrel cage rotor. The fans are normally capacitor start and run.

Question 9:  Which is the unit of electrical energy?

Answer 9: Answer: the unit of electrical energy is joule or watt-second  

Electrical energy in joule or watt-second  

= voltage in volts* current in amperes* time in seconds.

Joule or watt-second is very small for the measuring of electrical energy in the practical field purpose.

1 watt-hour = 1watt * 1 hour

                   = 1watt * 3600 seconds

                   = 3600 watt-sec

1 kilowatt-hour = 1kW * 1hr

                =1000watt* 3600 sec

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Curriculum vitae writing tips

Curriculum vitae

I will leave it to you to determine on the design and content of your

Curriculum vitae. There are several sources which can advise you on these

Aspects. Here are some transient pointers:

• Use the best quality paper you'll afford. 
• Use solely white or off-white paper.
• Don’t use a flowery exhausting cowl or binder along with fancy hard cover.
• Use a straightforward font like Arial and use identical font in your Covering letter.
• Never use a generic covering letter. Be specific in its content by.Bringing out one or 2 components of how you match what they're looking for. It’s not simply a wrapper for your CV!
• Your CV must get past that 1st thirty seconds once the recruiter has Picked it up. Imagine yours is simply one among-st fifty or sixty or additional Applications received. you wish your professionalism to square and not stand out as a result of you've used bright yellow paper!
• Pointing your achievements clearly in your CV; not merely list your past employers and job titles.
• accommodates any directions within the adverts like supplying your current salary – you'll want to try and do this inside your covering letter.

Imagine your delight, constant reader, when 2 weeks later you receive

on beautiful headed paper an invitation to attend an interview for this

Potentially wonderful new job! That’s when your exertions very

Begins. In Chapter a pair of I’ll explore what you would like to be brooding about

before you truly attend the interview.

Job interview Topics for Electrical and electronic Engineers (Part-3).

Electrical engineering interview topic:

Job interview Topics for Electrical and electronic Engineers (Part-3).

8. Diversity Factor:  

The ratio of Sum of individual maximum demand and Maximum demand in power station is called Diversity Factor.

Diversity Factor= [Sum of individual maximum demand/ Maximum demand in power station]

• Sum of individual maximum demand <Maximum demand in power station.
• Diversity Factor> 1

9. Load Duration Curve: 

In the Load Duration Curve the load elements are shown with respect to time. When the Load elements are arranged in the descending magnitude order in the Curve, thus the curve is known as Load Duration Curve.

10. Plant Use Factor:

The ratio of Station Output in KWh with respect to Plant Capacity and hours of use is called Plant Use Factor.

Plant Use Factor= [Station Output in KWh/ Plant Capacity * hours of use]

11. Node Equation: 

In the electrical circuit when a junction is formed with two or more pure elements (The elements can be Resistive, Inductive, Capacitive or an ideal source of current or voltage) and are connected to each other at their terminals are called nodes. The process of calculating this nodes and check their working basis is known as node equation. In the Node Equation usually the major nodes are considered. In the nodes, where more then two pure elements are connected in a junction is known as major nodes.

In the Node Equation there are two types of admittance. They are Self Admittance and Mutual Admittance. Some times the Self Admittance is called Driving point & Mutual Admittance is called transfer admittance.

12. Plant Capacity Factor: 

The ratio of Actual Energy Produced and the Maximum Energy that could have been produced in the power station is called Plant Capacity Factor.

Plant Capacity Factor= [Actual Energy Produced/ Maximum Energy that could   have been produced in the power station]

        = [Average Demand/Plant Capacity]

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Job interview Topics for Electrical and Electronics Engineers (Part-1)

Electrical Engineering interview question and answers:

Job interview Topics for Electrical and Electronics Engineers (Part-1)

1.Per Unit (pu) Quantities:

 The numerical per unit value of any quantity is defined as the ratio of its actual value to another arbitrarily chosen value of quantity of the same dimensions, assumed as the base or reference. It is basically used in one line diagram.

Per unit (pu) quantities|vivasolve.blogspot.com

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Per unit value ≈ (Actual value/ Base value of the same direction)

2. Advantage of Per Unit Representation:

• The Per Unit impedance value for apparatus of like rating lies within a very small range.
• The impedance of machines is specified by the manufactures of the machine in terms of per unit values.
• Per Unit value provides more meaningful information .The chance of confusion between line and phase voltage values on a 3-phase system is reduced.
• The computational disturbance or effect in power system is highly reduced with the use of Per Unit quantities.
• The Per Unit impedance which is referred on any side of a single phase transformer is the same.
• The Per Unit impedance which is referring to the either side of a three-phase transformer is the same regardless of the three-phase connection .Whether the connections are delta-delta, Y-Y, or delta-Y.

3. One –line Diagram: 

In the Electrical Circuits there are various components in a circuit diagram. Sometimes, it is needed to simplified electrical circuit diagram by omitting the completed circuit through the neutral and by indicating the component parts by standard symbols, in place of their equivalent circuits. Circuit parameters are not shown and a transmission line is represented by a single line between its two ends.

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