L & T  Placement Paper   Candidate Experiences   NIT Jamshedpur-8 Dec 2010

L & T  Placement Paper   Candidate Experiences   NIT Jamshedpur-8 Dec 2010

  • Posted by  FreshersWorld 
    7 Jan, 2012

    Hi Friends,

    I appeared for L&T (Heavy) interview on 8th October 2010. I am willing to share my interview experiences with you.

    L&T (Heavy engineering division) shortlisted 7 candidates from Electrical Engineering department on the basis of a written test. The test was completely of aptitude type. There were three sections ? verbal, logical ability and numerical ability. Questions were easy. A few questions were a bit lengthy. You better leave them, because they are time consuming. There was sectional cut off, So you need to be careful about time management.

    For the interview we were called to Kolkata on 8th of October 2010. Interview started from 9 am. I was on the 3rd number. The interview of the first guy went a bit too long(1 hour 20 minutes). We saw him coming out of the interview room uttering a few curse words.  It was scary for me. Then another guy went  inside and came out after about 45 minutes. This guy was a bit cool. Now it was my turn.

    I am presenting to you the line by line actual conversation between me and the interviewer.

    Me: May I come in, sir?
    Yes. Come in. (I entered the room.)
    There were two people in the room. Both technicals, no HR.
    Me: Good Morning, Sir.
    Interviewer: Good Morning. Sit down.
    Me: Thank you, sir.

    Interviewer: Have you prepared something?

    Me: Sir, I haven?t studied for 15?20 days, but before that I had been preparing.
    Interviewer: Why so?
    Me: Don?t know, may be I was just not able to concentrate on my studies.

    Interviewer: That?s good. It makes things easy for us. We test you on your basic concepts. If you study just before the interview, you are flooded with complex equations. And we don?t want to hear that. We just want to test your basics.

    Interviewer: Have you appeared for any other interviews?
    Me: Yes sir, I have appeared for 4 interviews till now.
    Interviewer: What happened in those?

    Me: They asked a few questions that I could not answer. Though the questions were simple. Like what?s the efficiency of a generator etc. etc.

    Interviewer: Now, you know the answer?
    Me: Yes, sir.
    Interviewer: Ok then, what should we ask you?

    Me: Whatever you want.

    Interviewer: (Showing  Surprise)Whatever we want?

    Me: I like control system and circuit theory, but I like machines too.

    Interviewer: You like machines too.

    Interviewer: So, you like circuit theory. Tell me, which bulb has a higher resistance  a 40 W or 60 W?

    Me: 40 W.

    Interviewer: How?

    Me:- Since, R is equal to V squared by P so more the P lesser the R.

    Interviewer: But, R is also equal to P by I squared. Why not apply that?

    Me: Because, bulbs are created with equal voltage rating not equal current rating.

    Ok, Good.

    Interviewer: Now, tell me the working principle of induction motors.

    (I start explaining, the stator, the rotor, the rotating magnetic field and shorted rotor, I say something on which they raise a question. I say, the induction machines works on the same principle as that of a transformer.)

    Interviewer: Then, why doesn?t transformer create a rotating magnetic field?
    Me: Because the windings in the transformer are not space displaced by 1200. For creation of rotating magnetic field, the stator windings must be space and time displaced by 1200.
    Interviewer: In a motor, which current is higher-the staring current or full load current?

    Me: The staring current is 5 to 6 times the full load current.

    Interviewer: Why so?

    Interviewer: Now, I start getting confused. First I tell them   that the effective reactance of the  machine goes on increasing with speed and then I tell them that the emf generated in the rotor decreases with time. (They give me 5 minutes to thing about it.)

    (I repeated the same answer after thinking (that the emf generated in the rotor decreases with time.))

    Interviewer: You are starting to disappoint us.
    Me: Sorry for this sir. 
    Interviewer: You like equations?

    Me: Yes sir.

    Then solve this: What can be the maximum speed of an induction motor in India?

    Me: A bit less than 3000 rpm.
    Interviewer: How?
    Me: Minimum no. of poles can be 2. Frequency is fixed (50 hz). So, by applying 120f/p.
    Interviewer: Find what could be this speed.
    Me: 2880 is a typical speed.
    Interviewer: Now, if we apply a rime mover and give a torque in the direction of the rotation, what would be the speed of the rotor?

    Me: It will go beyond the synchronous speed.

    Interviewer: What will happen, then?
    Me: The induction motor will start acting as an induction generator.
    Interviewer: What?s the use of this?
    Me: In the wind turbines.
    Interviewer: Why?

    Me: Because it can run at variable speeds.

    Interviewer: Any other use?
    Me: It can be used to perform regenerative braking.
    Interviewer: Where is regenerative braking used?

    Me: In the locomotives.

    Interviewer: Do you know how many such vehicles are running in India?
    Me: No sir.
    Interviewer: Any other use of induction generator?

    Me: I am not aware of any other use sir.

    Interviewer: Ok, you can  go.

    Me: Thank you, sir.

    I leave.


    Submitted by:

    Sourabh Anand.

    Electrical Engineering.

    NIT Jamshedpur.


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