Interview Questions Answers in Electrical Engineering

Question { 19736 }

what is the form factor of DC voltage

Answer

Addition to the above ans form factor = RMS value/Average value of a sine wave as there no such wave form exist means it is zero.

Is This Answer Correct ?

11 Yes

5 No

Question { 31872 }

what do you mean by mf of energy meter & its formula?

Answer

MF means the Multiplying factor.

Its nothing but the CT ration . as a big amount of the
current to be measured So direct Metering is not possible
hence CT operated meter is used

Formula :- if the CT ratio is 60/5 then metered reading
should be multiply by 12 which give the exact Power usage

Is This Answer Correct ?

28 Yes

8 No

Question { Power Grid, 11906 }

What is GIS (Gas Insulated Switchgear)

Answer

GIS means Gas insulated Substation.

In this all the Switchgear like Circuit breaker, CT PT,
Isolator all kept in one champer filled with SF6 gas 1t 4
kg pressure
It aquires less space

Is This Answer Correct ?

6 Yes

1 No

Question { NTPC, 28264 }

why threre are two parallel lines in transformer's symbol?

Answer

It mean the transfer of energy from one winding to anothor throw air gap based on mutual induction.

Is This Answer Correct ?

10 Yes

13 No

Question { 3401 }

what does hapen if suddently frequency doubled

Answer

It result in to over fluxing & saturation of core of
transformer . overheating of Winding of transformer & hence
tripping of Breaker from transformer protection

Is This Answer Correct ?

8 Yes

1 No

Question { 6634 }

what is ACB

Answer

Air Circuit Breaker

Is This Answer Correct ?

13 Yes

1 No

Question { 6634 }

what is ACB

Answer

Mr Pushpraj the question ask by tamil is ACB but your ans
related to the question is what is circuit breaker ??

how ever diversify the ans is the cictuit breaker which
make & break the current quenching medium will be air

Is This Answer Correct ?

2 Yes

0 No

Question { 6644 }

Why we are not using capacitor in line when load on Genset?

Answer

because the reactive prower produce by the Capcacitor may
harm the AVR of the DG set

Is This Answer Correct ?

4 Yes

2 No

Question { 20151 }

why we use iron corn in transformer instead of wooden core

Answer

Woooden is a insulator as it can not carry flux that's the
only reason

Is This Answer Correct ?

19 Yes

4 No

Question { L&T, 15851 }

what is looping circuit in electrical lighting circuits?

Answer

Dear friends.

The looping circuit is any circuit which is taken from the
first point feeding from the primary circuit ( primary
circuit is the first end of circuit from DB - MCB )

Is This Answer Correct ?

1 Yes

2 No

Question { 10628 }

AC voltage only create magnetic flux in coils, but in Solenoid
coil how 24V DC volt create flux and pick the plunger

Answer

Minakshi i am bit agree with you but i think that when a
current passing through the wound coil a magnatic field is
develod which pull the iron plunger hence the contactor
pics. in any from of current AC or DC magnatic field will
be develop the only diffrence is that in AC wave form is
sinosodule & while in DC it is linear...Please correct me
if i am wrong

Is This Answer Correct ?

4 Yes

0 No

Question { UltraTech, 8360 }

i have 2 motor of same rating. on no load condition one
motor take 1.6A but other motor is taking 4.8A. what is the
reason of this. please explain with proof.

Answer

Friend, if it is 3 ph then pls check the all 3ph are ok. If motor facing single phasing then this might happen

Is This Answer Correct ?

5 Yes

5 No

Question { KSEB, 6236 }

if transmission voltage expressed as the multipple of form
factor(1.11)........11,33,66,220 etc......then why
madakkathara substation(kerala) voltage is 400kv..not 440.....?

Answer

Please check it must be HVDC substation. The voltage rating for the same can be 400, 500 and 700 kv.

Is This Answer Correct ?

3 Yes

13 No

Question { 5086 }

in 33KV or 66KV system which connection is aviable on high
voltage transformer primary delta or star ?

Answer

Its delta only.

Is This Answer Correct ?

2 Yes

3 No

Question { 5876 }

WHY THE TRANSFORMER VALUE MEASURES IN KVA INSTEAD OF KW.

Answer

Meenakshi my view is also very much in line with you said
but addition to above i like to add that the transformet or
a generator are a source and are designed for the load
according to the characteristic & they have nothing to do
with the power factor . As the power factor is not counted
they rated in KVA ( Because KW = KVA x PF vise versa KVA =
KW/PF ) Please correct if something more can be added.....

Is This Answer Correct ?

10 Yes

3 No

virendra