Interview Questions Answers in Electrical Engineering

Questions / { abdul rahman }

Questions Answers Category Views Company eMail

Current Transformer's star point must face the protected object for the relay operation?

2 Electrical Engineering 15028

what is the use of static frequency converter and static excitation equipment? and where it is employed? for what?

Electrical Engineering 3033

define differential current and restraining current in relays. how to calculate it by mathematically? post the formulaes.

Siemens, VPEC,

4 Electrical Engineering 31974

last week we did the REF relay test by closing single pole (R phase) of CB and apply 380V at the primary of delta transformer. we get 33A at the primary of the R phase star end. but we get 380A at both R an B in delta side. how and why?

Siemens,

1 Electrical Engineering 2999

What is the function of restraining coil in differential relay? as well as restraining current?

Medical, Siemens,

8 Electrical Engineering 43418

what is spill current?

Adani, NPCIL,

4 Electrical Engineering 38123

what is back trip and re-trip in protection schemes? why these two? define me the exact function of these two?

Siemens,

1 Electrical Engineering 6156

what will happen if phases are not shorted with neutral in transformer impedance test? and if neutral is not connected with ground?

1 Electrical Engineering 3404

why and how fault current flows through ground?

1 Electrical Engineering 3633

what ll happen if neutral is not shorted with phases while doing transformer short circuit test & what ll happen if neutral is connected to ground?

1 Electrical Engineering 3156

why and where we use early make & late break contacts in protection?

Electrical Engineering 7588

Answers / { abdul rahman }

Question { 8304 }

what is surge arresters ?........

Answer

Surge means sudden increament. In electrical ckts, due to
some internal & external faults. sometimes the fault may
induce the overcurrent or overvoltage. to protect the
system from this spikes, we use the surge arresters.

Is This Answer Correct ?

5 Yes

0 No

Question { 8304 }

what is surge arresters ?........

Answer

my frnd ...

its not the limiter... it s a protective device acts as
limiter against only at faulty condition.

Is This Answer Correct ?

1 Yes

2 No

Question { 7434 }

What is the difference of grounding and earthing?

Answer

hi vikash...

u r almost right, but ground and earth are same. the word
gnd is used in European countries and earth in others...

let we come to gnd & neutral
* neutral may act as gnd.. but gnd never act as neutral.
* nuetral is the ref pt of the ckt. and gnd s the
protection pt.

and my frnds.. tell me more!

Is This Answer Correct ?

8 Yes

0 No

Question { Siemens, 31974 }

define differential current and restraining current in relays.
how to calculate it by mathematically? post the formulaes.

Answer

hi amudhanvanan.. thanks for posting the answer.. can u give
me the definitions and an example and define briefly!!!

Is This Answer Correct ?

3 Yes

2 No