Answer / abhilav vishwakarma

A contactor works on the principle of Electro-magnetism. IT
comes under the category of switch gears and all the switch
gears performs the same function of Switching.

A contactor consists of mainly 2 parts-Fixed and movable
jaws. the fixed jaws are firmly connected with the circuit
and is a provided with a COIL having movable jaw as soon as
current is allowed to flow from the circuit the COIL gets
charged and due to electromagnetic effect it attracts the
movable metal jaw, thus the circuit is complete with the
CONTACT provided by the movable jaw. this is the
functioning of contactor. When current through the circuit
ceases , coil demagnetises and movable jaw is pulled apart

Answer / seran

CONTACTOR IS USED TO AS SWITCH

Answer / kumar

low resistance flow of high electrons

Is there any design in the world a 220 KV transformer without breather …??????

2 Answers  

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What is the relation between the Peripheral speed(N) , no.of poles(P) and diameter(D) of a cylindrical rotor alternator ?

5 Answers   NTPC,

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why steady state stability limit is greater than transient stability limit ? How it can be explained ?

0 Answers  

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if a 3phase 100kva distribution transformer , 400 v,50 hz, 4-wire system is loaded at 160 k.w mostly 1-phase Lighting & Airconditioning split a.c load what will be the net effect on the power system in terms of voltage, powerfactor, current , efficiency of xformer

1 Answers  

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tell how current tranfomer works

2 Answers  

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Why we find the sensitivity for the CT's to check?

0 Answers  

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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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What happen when change order of CT in GIS feeder?

0 Answers  

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What is VCB? where it is installed at SP. What is SP?

0 Answers  

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How to work to the x'mer as a induction motor?

1 Answers  

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What is the accepted limit to increase the choosen transformer capacity over the load and why ?

1 Answers  

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what is difference of electrical and electronics

6 Answers   SSIL,

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