Interview Questions Answers in Electrical Engineering

Questions / { jain }

Questions Answers Category Views Company eMail

types of motors suitable for escalators with reason

2 Electrical Engineering 11545

how induction generator works?

Answer

Induction generator is nothing but the induction motor.
When the speed of induction motor raises above the
synchronous speed the motor will act as induction generator.
EX: Wind mill .

Synchronous speed= 120f/p

f=> frequency
p=> no. of poles.

Is This Answer Correct ?

1 Yes

0 No

Question { 34845 }

why transformer not work in dc

Answer

for mutual induction the alternating flux is needed. Dc
cannot produce alternating flux. so the transformer cannot
work with dc

Is This Answer Correct ?

30 Yes

4 No

Question { 29896 }

why the power cut problems occur in tamil nadu?
may i know the exact reason.plz

Answer

not only in tamil nadu, there is power problem in all over
india. due the gap between power generation and consumption
power problem occurs.

Is This Answer Correct ?

21 Yes

16 No

Question { Essar, 9022 }

why any inductive load need free wheeling diode?

Answer

the inductive load saving and releasing energy for a
particular intervals. the free wheeling diode provides the
return path to flow the current saved in the inductive load.

Is This Answer Correct ?

0 Yes

1 No

Question { NSN, 10780 }

How can i calculate heat load ?

Answer

H=I*I*R*t is the amount of heat produced in a conductor
when current is passed. the unit of heat load may be Joule.
I dont know exactly about heat load.

Is This Answer Correct ?

2 Yes

3 No

Question { ONGC, 6465 }

why using touble tube lamp use in factory?

Answer

can you give some details about stroboscopic effect Mr.
Rajendran.

Is This Answer Correct ?

0 Yes

0 No

Question { 8428 }

What is the difference between single phase, 2phase, and 3
phase motors?

Answer

for producing rotating magnetic field we need minimum two
phases. In single phase motor, we are calling single phase
motor but we are splitting the single phase into two phases
by capacitor. The phase angle between that two is 90 degree.
In case of three phase motor the R,Y,B phases produces
rotating magnetic field. The angle between three phases is
120 degree.

Is This Answer Correct ?

5 Yes

2 No

Question { 12216 }

what is meant by unity power factor?unity means one why dont
call 2,3,4......?

Answer

power factor is the cosine of angle between voltage and
current. the range of value of cos lies between -1 to 1. So
there is no chance to become power factor as 2,3,4 etc.

Is This Answer Correct ?

5 Yes

0 No

Question { 12485 }

can induction motor becomes as a generator. if yes how it is
possible. if there is a squirrel cage rotor.

Answer

when the speed of the induction motor exceeds the
synchronous speed the motor will act as induction generator.

Is This Answer Correct ?

2 Yes

0 No

Question { Moser Baer, 6216 }

what is the principal of starting of a three phase induction
motor.

Answer

The three phase induction motor is a self starting one as
the three phase supply produces the rotating magnetic field.

Is This Answer Correct ?

2 Yes

0 No

Question { 10780 }

when a motor is connected in parallel with the existing
motor the pf will change or not?

Answer

the Pf will change depend on the type of motor which is to
be connected as mentioned above.

Is This Answer Correct ?

3 Yes

0 No

Question { 8504 }

What happened when we give 2 phase supply to a 1 phase
equimpent. It's effect on equipment's efficiency and life?

Answer

voltage is the potential difference of two phases. so the
equipment will react depends on the voltage.

Is This Answer Correct ?

3 Yes

3 No

Question { 5203 }

why no load characteristics of generator also called as occ

Answer

in no load characteristics there is no load is connected at
the generator output. hence it is called as occ.

OCC= open circuit characteristics.

From the name itself(OCC) we can understand what it occ.

Is This Answer Correct ?

4 Yes

0 No

Question { 9058 }

why we don't discuss power facter in dc?

Answer

power factor is the cosine of angle between voltage and
current. In case of DC the angle between voltage and
current is zero. therefore power factor always remains 1.

power factor= cos(angle between vtg and current)
here angle = zero
therefore power factor = 1

Is This Answer Correct ?

21 Yes

2 No