Interview Questions Answers in Electrical Engineering

Question { 2616 }

What will happened, if field voltage change with 220 voltage to 110 voltage for a dc shunt motor?

Answer

If the field resistance and rotor voltage remain the same
,the speed of the motor almost doubles.

Is This Answer Correct ?

2 Yes

2 No

Question { Cranedge, 21488 }

How to find synchronous motor speed formula

Ns=120f/P
?....

Answer

What is Ns ? Is the formula required correct if Ns is rps ?

Is This Answer Correct ?

12 Yes

7 No

Question { Cranedge, 21488 }

How to find synchronous motor speed formula

Ns=120f/P
?....

Answer

The formula for f is P/2( one cycle) x N/ 60( rps),f =NP/120
,hence N=120f/P ,where N is rpm.

Is This Answer Correct ?

23 Yes

7 No

Question { 5448 }

what should be the BDV
value Of 11/132kv power
transformer

Answer

For voltages below 72.5 KV it is 40 KV Minimum

Is This Answer Correct ?

4 Yes

0 No

Question { NPTC, 6860 }

Which power will flow first if we switch on a motor? Active or
Reactive? How?

Answer

W and VAr are components of VA ,hence both may be co-incidental

Is This Answer Correct ?

2 Yes

2 No

Question { Tesco, 15494 }

what is the difference between main meter CT and check
meter CT?and what is the difference between main meter PT
and check meter PT?

Answer

In case of gen stations both are identical , there is no
difference at all

Is This Answer Correct ?

2 Yes

1 No

Question { TCS, 7461 }

why hv current transformers have big size ?

Answer

Insulation

Is This Answer Correct ?

6 Yes

1 No

Question { 5202 }

when ELCB breaks the circuit than INVERTER auto-connect the
circuit to the battery than how can the operetor is safe??

Answer

No ,ELCB is to be connected to circuit/load

Is This Answer Correct ?

1 Yes

1 No

Question { OPTCL, 8170 }

actual rated capacity of a disc insulator??

Answer

Electrically in KV and mechanically in KN

Is This Answer Correct ?

7 Yes

3 No

Question { 4333 }

In case of 3 phase motor why it is called single phasing by failure of one phare unless there is rest two phase are acting. ?

Answer

When one phase is missing ,the other two phases form one
phase of line voltage as neutral is not connected .If two
phases are absent as there is no return path, the condition
is zero phasing

Is This Answer Correct ?

2 Yes

0 No

Question { 5101 }

what is technical diffrence between table fan and ceiling fan

Answer

In case of table fan the rotor (armature) is inside the
field ,and in ceiling fan it is ouside

Is This Answer Correct ?

10 Yes

2 No

Question { AITM, 4513 }

how "rabbit ACSR" conductors are more efficient than "weasel
ACSR" conductors

Answer

The sectional area of rabbit conductor is more than that of
weasel ,hence less resistance and less I2R losses

Is This Answer Correct ?

3 Yes

1 No

Question { 3755 }

how can we solve the RMS value of alternative Qnty is .707 , explain detail .

Answer

It is a mathematical deduction resulting in Vrms=Vp/root 2
for sinusoidal wave.1/ root 2 =0.707

Is This Answer Correct ?

2 Yes

0 No

Question { AITM, 6487 }

How to convert KVA rating into HP rating?

Answer

KVA is apparent power and HP is real power.

Is This Answer Correct ?

2 Yes

2 No

Question { 2148 }

what the is the distance between 110kv termination point and
the ground. how to calculate

Answer

Just follow the I.E. Rules .Presently it is 4 m

Is This Answer Correct ?

1 Yes

0 No

k.prakashchandra