Interview Questions Answers in Electrical Engineering

Question { ITC Infotech, 3472 }

In our plant we are having 6.6 v motor wih MV drive running
frm last two years.udenly at some speed motor getting vey
vibrations what is the problem

Answer

May be hunting (due to failure of damper winding)

Is This Answer Correct ?

0 Yes

0 No

Question { 4816 }

Wat will happen if R-phase of an alternator is connected to B-
Phase of AMF panel fed from alternator

Answer

It may effects on load due to ronge phase
sequncy conection

Is This Answer Correct ?

1 Yes

0 No

Question { Khetan, 21666 }

What is the GNA & MNA in armature reaction of Dc Generator

Answer

where emf is induced zero then it called as a MNA (MAGNETIC NUATRAL AXIS)

Is This Answer Correct ?

47 Yes

11 No

Question { Emco, 7381 }

why starter use to on a motor

Answer

At the starting time 'EB=0'(back emf) so that
motor draws a 2 to 3 times of its full load current
and which cause to damege the winding. ummm....
That is why using stater to reduse starting current

Is This Answer Correct ?

0 Yes

0 No

Question { 6857 }

1.why motor rating in kw instead of KVA?
2.why alternators rating in KVA instead of KW?.
3.why transformer rating in KVA instead of KW?.

Answer

All ac sources are rated in kva where alternator
&transformer and all ac loads are rated in kw
where motor

Is This Answer Correct ?

0 Yes

2 No

Question { 4318 }

What is a charge.?

Answer

Part in atom

Is This Answer Correct ?

2 Yes

0 No

Question { 4582 }

why power factor is only cosine angle not sine angle?

Answer

Let assume pi=0 cos(0)=1 it means there phase
angle(pi) is 0 then p=vicos
(pi)=vi*1=vi take a
sin instead of cos sin(0)=0 then p=visin(pi)=vi*0=0
that is why choose cos

Is This Answer Correct ?

0 Yes

0 No

Question { 8090 }

why do we connect voltmeter in parallel,why not in
series,and why do we connect ammeter in series why not in
paprallel...

Answer

Current same in series and voltage same in parllel
so when we connect A meter in series and V
meter in parallel it measure correct value

Is This Answer Correct ?

3 Yes

2 No

Question { GSK, 6907 }

One 15kw motor Why we used star delta feeder?why not used DOL
please explain in details

Answer

We can use dol stater up to 5HP (dol stater can
not control starting current of motor but protect
by them up to 5HP). We have been using dol
staters to lower rating ac motors due to low cost.

Is This Answer Correct ?

3 Yes

0 No

Question { 2618 }

What is ferrite affects and what is disadvantage of ferrite
affects.

Answer

Ferranti effect: The receiving end voltage is more
then the sending end voltage due to presence of
capacitence bitween two live conductres of the
transmission line

Is This Answer Correct ?

1 Yes

0 No

Question { Matsui Technologies, 3928 }

Which Motor used in Fan's Motor ?

Answer

Single phase induction capacitor start and run
motor

Is This Answer Correct ?

3 Yes

0 No

brdganesh