Interview Questions Answers in Electrical Engineering

Question { 8548 }

what is VFD and how to save the power by using VFD?

Answer

Frequency decrese then flux increase & hence current decrese

Is This Answer Correct ?

0 Yes

2 No

Question { 5279 }

its Kva and Kv are same?

Answer

KV means the kilo volt it indicates the voltage level of
the system however KVA is the power consumed by the system
is including Amps.

Is This Answer Correct ?

2 Yes

1 No

Question { 5965 }

What is bushing?

Answer

Bushing is one kind of insulater but in this the conductor
is passing thorew ( From center ) of the bushing ( Ex . For
transformer )

Is This Answer Correct ?

7 Yes

1 No

Question { 4648 }

How is the air circuit breaker quenching the arc. If it is
by air means, where is it come from?

Answer

Air Ciruit breaker is the one in which the quenching is
happen in precense of air mean there is no other thing is
provided. In this breaker the opening in closing of contect
happen in natural autmospher & hence the are is produces ,
to quench this arc the arc chute is provided the same .

Is This Answer Correct ?

4 Yes

1 No

Question { Ramky, 63528 }

why CT ratio stand for 50/5, 100/5, 25/5.

Answer

Generally allThe CT operated meter is designed for a
capacity arround 5 A , the ct ratio 50/5, 100 / 5 means the
secondary current of the secondary winding will not exceed
more than 5A

Is This Answer Correct ?

106 Yes

17 No

Question { Essar, 5463 }

what is tha online tapping and offline tappchange?
which side connected primary or secondary and explain ?

Answer

Tapping is privided in the transformer to get the desired
voltage in step.

Generally Primery is used for tapping because usually High
voltage winding is wound on the outer side so that it is
easy to take the tapping on the top of the transformer.

Is This Answer Correct ?

5 Yes

2 No

Question { Essar, 3440 }

what is elevation lamp?where its used?

Answer

I think it is aviation Lamo. The lamp which continiously
blinks & it is installated at the Chimney or a building
which is high to warn the aircrafts.

Is This Answer Correct ?

7 Yes

0 No

Question { Essar, 3440 }

what is elevation lamp?where its used?

Answer

Question contain the ans too. the lamp which is used to
warn the aircraft for something danger of it ( highrise) (
it is installated on high structuctures like chimney ,
telecom towers etc...)

Is This Answer Correct ?

2 Yes

0 No

Question { 5409 }

ther is any difference if we use 240 V A.C,50 Hz,1 Ph. in
place of 230 V A.C,50 Hz,1 Ph.

Answer

Not muuch diffrence

Is This Answer Correct ?

1 Yes

0 No

Question { 8200 }

HOW TO CALCULATE THE WIRE SIZE FOR THE GIVEN LOAD?

Answer

By givan load you can calculate the current & as per
standrd table you can chose the size of the cable.

Is This Answer Correct ?

9 Yes

0 No

Question { Engineers India Limited, 7098 }

What are the protection schemes used for protection of
transformers ?

Answer

OT, WT, Bucholz

Is This Answer Correct ?

2 Yes

4 No

Question { Lanco, 8530 }

what is the need of representing AC power in sinusoidal
waveform? why not in square or rectangular etc...

Answer

Beacause in AC voltage , the voltage increses from ZERO to
MAX gradually also Maz to zero .

The same way Zero to -Max & -Max to zero

This is happen gradull, as voltage in AC circuit for 1
cycle does not remain a same for even a short period of
time. that is the reason why we consider it sinusodial
insted of sqqure or rectungular.

Is This Answer Correct ?

6 Yes

3 No

Question { TVS, 13372 }

Why the earth terminal pin is larger than phase and neutral
in three pin plug top>

Answer

At the time fault multiple time of the fault current is
generated so to give a proper path to the earth the pin
size is bigger in comparision to the other two

Is This Answer Correct ?

11 Yes

2 No

Question { 12828 }

We have laid the single core Armoured cable 7 nos ( 2 each
phase & 1 neutral ) to cater our electrical load .
the issue is though we have Glanded the cable both the end
also givan the earthing to the panel both the end we are
facing a heavy sparking at the gland side. what could be
the reason.

Answer

Mr sharma Please note that we have a stady system & all the
equipment is properl earthed . there is no such load like
welding machine is existing.Is it cerculating cureent ??????
as this is a single core cable

Is This Answer Correct ?

1 Yes

0 No

Question { 12828 }

Answer

Dear Ravi,

we are having a load around 300 KW with 200 KW lighting
load & 100 KW of Motive load.

Also note that we have a stable system with balance load

Is This Answer Correct ?

0 Yes

1 No

virendra