Interview Questions Answers in Electrical Engineering, Electronics Communications, Instrumentation

Question { 42480 }

what is the difference between ac and dc generator

Answer

all generators produce ac current as output.....but incase
of dc we use commutator to convert it in dc current

Is This Answer Correct ?

146 Yes

29 No

Question { IBM, 86191 }

what is the function of starter & choke in the tube light
set & how choke give 1000 volts while switching on.

Answer

function of choke:it produces high voltage in the tubelight
which is essential for ionisation of the gas present in the
tubelight.

Is This Answer Correct ?

245 Yes

54 No

Question { 6028 }

Give two basic sprrd control scheme of DC shunt motor.

Answer

1. by using flux control method:in this method a rheostat is connected across the field wdg to control the field current.so by changing the current the flux produced by the field wdg can be changed, and since speed is inversely proportional to flux speed can be controlled
2.armature control method:
in this method a rheostat is connected across armature wdg.by varying the resistance the value of resistive drop(IaRa)can be varied,and since speed is directly propotional to Eb-IaRa the speed can be controlled

Is This Answer Correct ?

8 Yes

0 No

Question { 15363 }

how we select fuse rating for motor?

Answer

fuse rating is selected depending upon the rated current
which will be specified in the name plate details of the
motor.
usually for load test,
fuse rating=(125\100)*rated current

Is This Answer Correct ?

31 Yes

8 No

Question { 18820 }

What is meant by locking of rotor in synchronous motor?
Explain me locking in detail?

Answer

force of attraction exists between two magnets......in such
a case when one of the magnet is moved in one direction,the
other magnet also moves in the same direction with the same
speed with which the first magnet was moved.the above
principle is called magnetic locking.this is the principle
of synchronous motor

Is This Answer Correct ?

26 Yes

6 No

Question { 9656 }

why we used to transmitt the power at higher voltage why
not at lower voltage

Answer

at high voltage I^2r losses r less

Is This Answer Correct ?

8 Yes

0 No

Question { 9248 }

which motor gives constant speed?

Answer

dc shunt motor

Is This Answer Correct ?

7 Yes

3 No

Question { Wipro, 27002 }

what is mean by current

Answer

the rate of flow of electrons.
I=q/t

Is This Answer Correct ?

24 Yes

9 No

Question { ONGC, 14285 }

what is mean impedance?

Answer

the ratio of voltage/current in case of ac supply is known
as impedance.
z=r+j(xl-xc)
where xland xc are inductive and capacitive reactance
respectively.

Is This Answer Correct ?

45 Yes

7 No

Question { 9219 }

why we use to transmit the power in three phases intead of
single phase ?

Answer

1.in case a fault occurs in a line ,unlike single phase the
continuity of power supply will not be affected i.e the
other two lines of 3 phase will not get affected.
2.single phase loads can also be operated by connecting it
between line and neutral.

Is This Answer Correct ?

7 Yes

5 No

Question { 10027 }

defination of generator

Answer

the machine which converts mechanical energy into electrical
energy.

Is This Answer Correct ?

7 Yes

1 No

Question { 5973 }

howmany types of compresor is there? and how to calculate
compresor capacity?

Answer

reciprocating type:it is of 2 types,single stage and
multistage compressor.

rotary type :it includes axial flow compressor and
centrifugal compressor

Is This Answer Correct ?

5 Yes

0 No

Question { 9480 }

wt is the function of transformer?

Answer

transformer is a device that is used to transfer energy from
one circuit to another without any change in frequency

Is This Answer Correct ?

8 Yes

1 No

Question { 6215 }

state application of relay in transmission line?

Answer

in case any fault occurs in the transmission line, it is
used to isolate the healthy side from the faulty side i.e it
is used to protect the line from total damage.

Is This Answer Correct ?

4 Yes

1 No

Question { 10760 }

why use squareroot in flow measurment by dp transmitter?

Answer

its because the flow rate is proportional to square root of differential pressure.

Is This Answer Correct ?

4 Yes

0 No

sindhu