Series: Subject:

Electrical Engineering Interview Questions

Showing Questions 1 - 20 of 463 Questions
First | Prev | | Next | Last Page
Sort by: 

Impedance matching

Asked By: Divya Jyothi | Asked On: Jun 24th, 2014

Explain briefly about impedance matching and how the transformer serves in impedance matching?

Answered by: sandeep on: Oct 28th, 2014

Impedance matching is used to transfer the max. power...transformer serves the purpose of impedance matching by adjusting turns ratio.

Phase and neutral

Asked By: srinu08 | Asked On: Sep 17th, 2013

What is the difference between phase and neutral?

Answered by: saadsms on: Oct 26th, 2014

1- in one phase case : Phase is supply voltage weather neutral is returning path the same current for that supply voltage. 2- in three phase case : - in balanced load current returned to earth = 0 - ...

Answered by: manwendra on: Oct 25th, 2014

Neutral  is basically reference zero voltage for phase...


Asked By: tonmoy11105063 | Asked On: Oct 25th, 2014

Describe how high currents and voltages are measured with the help of instrument transformer?

What is the main difference between current and voltage?

Asked By: Svelmurugan | Asked On: Jul 15th, 2012

Answered by: sanjay yadav on: Oct 24th, 2014

Current is the electron motion through external force.              External force is applied voltage.

Answered by: lalit on: Sep 27th, 2014

Voltage is the driving force that causes the current to flow in the closed path of the circuit. so if there is no voltage , there would be no current in that part of the circuit across the element

Difference between active & reactive power meters

Asked By: saadsms | Asked On: Oct 18th, 2014

In meters with electromechanical " rotating disk " what is the difference between the meter of reactive powervarhm and the meter of active power whm.?? working theory and internal structure.?? thanks

Motor frame size

Asked By: surendra sharma | Asked On: Aug 11th, 2008

What is meaning of "motor frame size"? What is use to determine the motor h.P?

Answered by: ashish srivastava on: Sep 28th, 2014

This means the distance between the horizontal center axis of motor and ground.

Answered by: sindhejs on: Feb 17th, 2009

For the coupling (motor to any other devices) purpose the motor frame come into picture. Its very important to match the frame size, otherwise motor may damage. To calculate the motor rating, it is required to have motor voltage rating and current rating.

DC voltage frequency

Asked By: sintayew | Asked On: Nov 9th, 2009

What is the frequency of DC voltage?

Answered by: Mukesh Rathi on: Sep 25th, 2014

Frequecy of dc is zero .

Answered by: chandan mukherjee on: Sep 13th, 2014

There are two types of DC .
(I) steady state DC
(ii) pulsating DC

the frequency of pulsating DC is 2 times of ac frequency
but the frequency of steady state dc is zero.

Sc test

Asked By: goel1982 | Asked On: Feb 3rd, 2010

Why sc test is performed on lv side?

Answered by: Umesh on: Sep 25th, 2014

We generally performs Short circuit test keeping initial voltage at lower value and then gradually increases it up to the level to get a full load current (or Max) through testing device or circuit. B...

Answered by: KM Mahesha on: Jul 22nd, 2014

Load are in LV side and also max SC faults occurred in Load side. If SC Faults occurs protect load and Net work system

Why voltage is always a multiple of 11 ?

Asked By: rajneesh chaudhary | Asked On: Jul 19th, 2014

Answered by: roshan kumar jha on: Sep 24th, 2014

Coz of form factor generally

Answered by: kumar sundram on: Sep 19th, 2014

If you notice that 765,1200,400kv is always assumption based questions not in reality.But any practical point of view it is always multiple of 11 because of form factor dear.

At what condition a synchronous motor acts as a synchronous condenser?

Asked By: madhulathaoshapaka | Asked On: Jul 17th, 2014

Answered by: prasad jandhyala on: Sep 6th, 2014

Synchronous motor acts as a condenser when it is operated at no load and over excited state. synchronous condensers are mainly used for power factor improvement.

Answered by: Pramod kumar on: Sep 3rd, 2014

Synchronous motor behave as a condenser when it uses at no load and leading pf.

Why is the transformer rated in kva?

Asked By: bernard | Asked On: Sep 6th, 2007

Star Read Best Answer

Editorial / Best Answer

Answered by: NagaseshaReddy.M

Answered On : Sep 10th, 2007

kVA is the unit for apparent power. Apparent power consists of active and reactive power. Active power is the share of the apparent power which transmits energy from the source (generator) to the user. Reactive power is the share of the apparent power which represents a useless oscillation of energy from the source to the user and back again.

It occurs when on account of some »inertia« in the system there is a phase shift between voltage and current. This means that the current does not change polarity synchronous with the voltage. But the heat generated in a winding as well as the eddy current losses generated in a transformer core depend on the current only, regardless of whether it aligns with the voltage or not.

Therefore the heat is always proportional to the square of the current amplitude, irrespective of the phase angle (the shift between voltage and current). So a transformer has to be rated (and selected) by apparent power.

Answered by: ashutosh on: Sep 5th, 2014

Because of core losses and iron losses as core losses are measured in amps and cu losses in voltage ....this is definatly reason for the rating

Answered by: kalyan sundar dalai on: Jul 5th, 2014

Transformer loss depends on voltage & current and its efficiency is depends its losses obviously its rating in kva.

Why stones are used in switch yard ?

Asked By: pankaj rawal | Asked On: Aug 14th, 2011

Answered by: akshay on: Sep 3rd, 2014

To avoid the moisture from surface bcoz it can make conducting medium with TX line.

Answered by: praveen on: Aug 13th, 2014

Also to avoid the moment of reptiles..

What will happen if we apply DC volt across transformer?

Asked By: dhirendra singh | Asked On: Jul 21st, 2007

Answered by: Sunilkumar Rathod on: Aug 10th, 2014

As we know all, the frequency of DC is zero. So inductive reactance is zero. Therefore it will damage primary coil

Answered by: Shashank Lohia on: Jul 24th, 2014

Transformer coils are generally designed with a very high inductance and low resistance values. When DC voltage is applied to the primary of transformer, the change in flux would be zero, so no voltag...

Suggest me how to get electrical jobs or relevant jobs ?

Asked By: Smita G | Asked On: Jul 2nd, 2014

Hello sir/madam, i have completed be in electrical with 65% aggregate.Even after trying for many jobs I didnt get desired job so currently am working in bpo sector. So suggest me to get good job related to my educational background please....

Answered by: sudhir on: Jul 29th, 2014

Learn Electrical Design.

Electrical machines

Asked By: gguruprakash27 | Asked On: Jul 25th, 2014

Why we are preferring 4 pole alternator in the production of electric power instead of 2 pole alternator ?

Answered by: s.asokan on: Jul 28th, 2014

Speed is depend on number of poles and frequency. Commomnly all motors are used 1500 RPM and Indian standrad frequency 50hz also motor used 4 pole. In rare case nearly 3000 RPM (high speed motors, ht alternators) machines are used 2 poles.

Answered by: RAKESH KUMAR GHOSH on: Jul 28th, 2014

Because, speed is inversely proportional to number of poles for synchronous machine.

Why the supply frequency in india is 50hz

Asked By: madhulathaoshapaka | Asked On: Jul 17th, 2014

Answered by: liyakath shaik on: Jul 24th, 2014

the  frequency  is  depends  on  speed   synchronous  speed= 120f/p  from this  we  know  that f= Np/120 in  india  speed  of alternator is  nearly  about  3000  rpm  and  the  p...

Transformer design and construction

Asked By: PRASAN KUMAR PADHY | Asked On: Jul 6th, 2014

What is shape of the coils used in a transformer ? Choose the correct one from the bracket (rectangulAR,oval,circulAR,cylindrical ) & justify it with detail reason. is transformer a machine ?Choose the correct one from the bracket (yes/no) & justify it with detail reason.

Answered by: manikandan.l on: Jul 18th, 2014


Answered by: AlHussein Abdallah on: Jul 16th, 2014

Star connected rotor of induction motor has a standstill impedance of (0.4+4j)ohm per phase and rheostat impedance per phase is (6+2j)ohm. The motor has induced voltage of 80v between slip-rings at st...

Electrical interview question

Asked By: Kutubuddin Molla | Asked On: Oct 12th, 2011

1)what is the latest generation of circuit breakers called? 2)what are the special cables required for explosion proof wiring? 3)what are the different types of soft starters for large motors? 4)what is the similarity and what is the difference between relays and plc?

Answered by: ayrton on: Jul 8th, 2014

Programmable logic controller is abbreviated as PLC. It is a sort of micro controller used in industrial environment. It is highly resistant to environmental factors such as dust, humidity etc. Howe...

Answered by: Krunal R on: Apr 14th, 2012

1. SF6 Circuit Breaker

Explain about brush and brushless alternators ?

Asked By: Lawrence Didy Ebirim | Asked On: Aug 18th, 2011

Answered by: rathod abhishek on: Jul 5th, 2014

Brush is used for collecting current for commutator and send to rotor and rotor rotate . in brush less alternator there is no need of brush....

Answered by: Udhayakumar on: Jul 1st, 2014


Phase identification

Asked By: elexengg | Asked On: Mar 24th, 2009

In a three phase system three wires are of colour red, yellow and blue are used to discriminate each phase. Now how will you identify each phase wire without knowing the colour and without any pre information?

Answered by: Walt Slade on: Jun 30th, 2014

As I said above, there are devices that use a reference and GPS clocks. For example the EDM AP-30 can be touched onto an energized, unlabelled wire and it will display the degrees leading/lagging from...

Answered by: prem on: Jun 29th, 2014

When there no color code how to know r y b and how to test it

First | Prev | | Next | Last Page





twitter fb Linkedin GPlus RSS


Interview Question

 Ask Interview Question?


Latest Questions

Interview & Career Tips

Get invaluable Interview and Career Tips delivered directly to your inbox. Get your news alert set up today, Once you confirm your Email subscription, you will be able to download Job Inteview Questions Ebook . Please contact me if you there is any issue with the download.