Answer / t lakshmi narayana

Imagine a clock.There are 60 divisions.A seconds hand moves
each division by 1 sec. Similarly Stepper motor is having
360 divisions.Each division is 1 degree Electrically apart,
Total 360 degrees. As Field pulses are given the rotor
rotates in steps.

If the Brush of DC motor is shifted by 90 deg, then what happens to voltage and torque? Both voltage and torque are zero. how to justify the answer?

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i am swathi, b.tech 4th year. In smps(switched mode power supply)we are using diodes,mosfets,igbts for controling of current. And my question is why we did not use thyristors(scr)? it is also act as a switch,then what is the drawback of scr as compared to above transisters> if we use the scr,then what is happening ? plz give reply as soon as possible bcoz i am doing project on smps. plz frnds i want ans for that. if anybody know the ans plz send to my e-mail id /swathi.tadakapally@gmail.com/

5 Answers   EEE, TCS,

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Define availability (operational)?

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What is the significance of %Z in case of transformer?

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sir my exam is on 19/6/2013 under electrical branch pls send me sample aptitude questions as well as sample technical questions for jindal steel and power company

0 Answers   Jindal,

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What is the approximate value of stacking factor?

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it is used to measure the potial difference between two point?

2 Answers  

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How to select HT/MV cable size ?

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Based on CPI/CGPA they shortlist the candidates & than directly start Interview so there is no Written Exam or GD Only PI.Interview held @ MNNIT , ALLAHABAD On-Campus on 6th,Aug, 2007 & the Questions asked to me by Interview Board ( 4 People) are from HR/SummerTraining/BTP/Subject-core, POWER SYSTEM & MACHINE. time duration of I/V is about 15-20 Minutes. HR- Q.1 Name,hobbies & About family background ? Q2.What u know abt NTPC ?? Q3.Why u want to choose NTPC as ur Carrier's starting i.e power sector not any other Oragnisation or sector ?? Techincal Questions- Q1.What is the reason for transformer Noise ?? Q2.Which material is used for making Transformer oil & How u measure its dielectric strength & Name the test ? Q.3 Which Machine u will prefer 2 use if flammble gases are coming out at a place & why ?? Q4.What is relation b/w Transmission Lines & Communication Lines ? Q5.What is the maximum capacity Synchronus Machine & total powerGeneration in our country ? Q.6 In india Power generation is at 50Hz while in America its 60 hz ,why so ?? Advantage or disadvantage ?? Q.7 Maximum Generation Voltage in india ? Q8. What is the Voltage regulation & why its required n how much is permissible ? & causes of voltage variation ?? Q.9 Why electric shock is feel ?? n in a Electric Train why we didnt feel that ? Q.10 Have u seen/ experience of any power plant/ industry related to the power sector ? so these are the questions which not too diffcult i think was asked to me.

6 Answers   NTPC,

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why AC voltage source are generate as 50 Hz ?

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The power supplied to a 50mH inductor from a 120V, 60Hz source will be

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Why the Transformer connection is changing in different transformer?(Like Star & Delta,Delta & Delta,Star & Star,Delta Star) From that connection where it is used?

2 Answers  

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