Interview Questions Answers in Electrical Engineering

Questions / { vijay balu raskar }

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Answers / { vijay balu raskar }

i want to know is it possible to generate usefull power by
coupling generator with motor & supply gives to motor by
battery source then generator generates power. remove the
battery source given to the motor & feed the supply from
some of the generated power supply to the motor & motor
runs continously. generator generate power contnously.is it
possible ?

Answer

No,never.its impossible.because, total supply is zero. As battary create some kind of electricity. It is very less for motor to run.

Is This Answer Correct ?

0 Yes

2 No

Question { 4868 }

. Is there a simple method to measure the horsepower of a
small motor (1-3 hp) for a non-technical person

Answer

Yes, it is very easy to measure by non-technical person by force or pressure handling capacity of the motor which is practically done in many rural non technical persons.
Also, we can calculated or measured by wattmeter for measurment.
1HP = 746 Wattmeter
and by multiplying we will get more.

Is This Answer Correct ?

1 Yes

1 No

Question { HAL, 7536 }

Is it possible to use AC supply insted of DC supply in trip
coil operation? if not, why?

Answer

Main reason is property of Inductance.

Is This Answer Correct ?

1 Yes

0 No

Question { Siemens, 9702 }

how mach PF mainten in DG

Answer

Yes, power factor is 0.85 lagging or more than this. Also, based on operating loads.Because, power factor is the ratio of active power to the appearant power.

Is This Answer Correct ?

0 Yes

1 No

Question { 7166 }

Why cant we connect the motor output to generator and then
generator output to motor ?

Answer

Generation of electricity is done by using generator. Generator makes electricity as per number of rotations. Higher the number of rotations high will be generation. If we connect motor output the generator then speed of the generator is low as compare with motor and usually output of generator. Motor required high starting current / we can say torque. Hence, we can't.

Is This Answer Correct ?

0 Yes

0 No

Question { 5815 }

how to improve power factor correction?

Answer

Power factor is ratio of active power to appearant power. we have to use capacitor bank to improve power factor.Also, removing inductive loads. As per power factor error.

Is This Answer Correct ?

1 Yes

0 No

Question { Reliance, 9599 }

WHAT IS DIFFRENCE BETWEEN 3 PHASHE AND 1 PHASHE

Answer

1 phase means it carry currents by 0 degree phase shift and 3 phase means it contains 3 phases which is 120 degree apart from each other.

3 Phases carry currents equally in each phases by 120 degree apart.

Is This Answer Correct ?

25 Yes

1 No

Question { 3747 }

What is the problem if we connect a weak capacitor to the
system? is that profitable or Loss?

Answer

It's not profitable but loss. Capacitor is used for stable performance. If capacitor is weak then it will effect to the system.Like capacitor bank, it is used for to improve power factor and ironically performance.

Is This Answer Correct ?

5 Yes

0 No

Question { 8839 }

Why is DC use instead of AC for protection and control
circuits?

Answer

DC is constant & continuous source. For protection & control it is suitable. Also, having quick responce without disturbance & variation. In ac opposite of dc.

Is This Answer Correct ?

2 Yes

1 No

Question { Cushman Wakefield, 9607 }

What Factors should we consider while synchronizing two DG Sets?

Answer

Power factor, Voltage and frequency should be same.

Is This Answer Correct ?

3 Yes

4 No

Question { 8350 }

why transformer are not used in D.C SUPPLY

Answer

AC able to generate varying flux because of variation property.
DC unable to generate flux because of constant property.

generated Flux have to travel from primary core to secondary core which is not possible in the DC mode.

Due to this reason, DC are not used in the transformer.
But, if we use it then transformer will burn as per rating of DC voltage.

Is This Answer Correct ?

2 Yes

1 No

Question { 5572 }

In the transformer, in which form we see the losses of
transfprmer ?

Answer

There are Two type of losses in the transformer:-
1) Copper Losses
and
2) Iron Losses or Core losses

Losses are in the form of Heat and electrical bills are going high.

Is This Answer Correct ?

2 Yes

0 No

Question { 7855 }

what is difference between fuse and circuit breaker?

Answer

Difference between fuse and CB is tripping process and main difference, CB is highly sensible than Fuse.

Is This Answer Correct ?

0 Yes

0 No

Question { 8544 }

in a transmission line if the load is suddenly increased in
the receiving end of the system the phase shift will ?

Answer

As power flows along a transmission line, there is an electrical phase shift, which increases with distance and with power flow. As this phase shift increases, the system in
which the line is embedded can become increasingly unstable during electrical disturbances.

Simply, load suddenly increases phase shift will increases.

Is This Answer Correct ?

9 Yes

1 No

Question { 16533 }

what is disadvantages of high power factor

Answer

Power factor should be Unity.
If higher or lower than this then losses are varies.
Losses increases with power factor value.

Is This Answer Correct ?

2 Yes

6 No