Answer / biswajit sahoo

IT DEPENDS TYPE OF LOAD IT VARRIES FROM 20 S TO 80 SEC

Answer / srinivas

In star delta starter first star contactor will be in action after some delay time delta contactor will come in to picture and no need of time delay for star contactor.

At the time of starting motor ohmic resistance is zero and hence the back EMF zero. So it will takes more current, it may cause winding damage. So we have to reduce the starting currents. it is possible by connecting the motor terminals as star at the starting. Time delay range depends on what type of load used in motor and rating of motor. Normally the time delay range will set to reach above 70% of the motor load.

What are the neccessary safety arrangements before commissioning of HV substation?

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Tell me in detail about c.t. And p.t. ?

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1 sq.mm alluminum cable hou much current caraing capacity

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if u give d.c. supply to transformer primary then what happen.&why??????????????

4 Answers   DCS, DRDO, HCL,

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How to do fabrication , busbar and wiring cost for : 1. LT Panels 2. C& R Panel

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How we calculate airgap between phases & terminal box of the transformer? any formulae.

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if we supply DC power to AC transformer then what its result?

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Can u explain : what is supply for train (whether a,c or d.c ).I know that supply is 25000v a.c .But there is rumour that supply is D.C. And also explain how lights and fans inside the trains are working ,and what type of motors are used in trains whether D.C motors or induction motors .If d.c motor, how it gets supply.If traction motors are used then what are traction motors and its functions and how it differs from other motors and also explain about locomotive . y d.c series motor in train.train wheels r driven by D.C shunt motor ,at what voltage,and at what speed. please reply..............

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why do we use bundle conductors instead of using single conductor of larger size for high voltage transmission?

7 Answers  

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please send me previous year questions of jspl through which i could prepare myself for the test.

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In parallel operation time both NGR’s close or not close if both close what will happen

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I got shortlisted in RRB thiruvananthapuram for the post of Junior Electrical engineer, waiting List - 7. i want to know about the validity of the current list and chance to get the job please help anybody knws abt it,, thank you

1 Answers  

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