Interview Questions Answers in Mechanical Engineering, Electrical Engineering

Questions / { abid ali khattak }

Questions Answers Category Views Company eMail

What is the deff betwen Two stroke engine & Four stroke engines. Difine Theoretcally & Practically.

11 Mechanical Engineering 13655

Supose we have one 220v A.C fan.if we provide 220v D.C what will be happen?

13 Electrical Engineering 23211

What is the deffrence between Siemens S7-300 & S7-400 PLC?

ADC,

4 Electrical Engineering 30916

Which Programming software are use for Allen bradley PLC's?

ADC,

16 Electrical Engineering 22601

Answers / { abid ali khattak }

Question { century, 6135 }

in 50 mw generator if field is open in full load running
condition what happen and for protection which relay used?

Answer

Usually we are using a loss of excitation rely. Which
always getting a sense from the field excitation circuit
continueslly during the runing condition of Generator.

Is This Answer Correct ?

9 Yes

0 No

Question { 6579 }

how do find power factor in practically and what it means?

Answer

For the practically experiment of power factor we need to
connect the two type of same Wattage AC load with the
circuit. 1- inductive load. 2- Resistive load. and then we
need to be measured the current of both laod. We will find
that the inductive load getting more current then resistive
load.( lagging & Leading)
Beacause of inductance which induced in the inductive load.
which always oppose the provided EMF.

Is This Answer Correct ?

12 Yes

3 No

Question { ABB, 69631 }

Why DC excitation is used for alternators? Why cant it be AC?

Answer

As you well known the DC is direct current which doesn't
change its direction. therfore we always using the DC
excitation for Generation due to continues induced magnatic
field for proper excitation.

Is This Answer Correct ?

131 Yes

43 No

Question { NTPC, 48570 }

identify the components of the tube light and explain how
they function???wat is inside the fluroscent tube???how it
works???

Answer

Fluroscent consit on: Element, Fluroscent powder and gas.
Working Principle: When we apply the voltage to the
furoscent tube through starter. its creat a suffeciant
current and the gas which inside the tube make short the
element, which located both end of tube light.

Is This Answer Correct ?

32 Yes

37 No

Question { Sail, 61392 }

why dc power can not be used in transformer?

Answer

Because of Meutial.induction.and sign wave frequency
induction.

Is This Answer Correct ?

14 Yes

38 No

Question { 6567 }

what is the differnce between ac and dc?

Answer

AC: means in electrical terminology (Alternating current.
its change its direction continueslly.
DC: means in electrical terminology (Direct current). its
doesn't change its direction.

Is This Answer Correct ?

12 Yes

0 No

Question { 8617 }

WHY DIODE IS CONNECTING ACROSS SWITCHES

Answer

Mostly Diode is using in Electrical Circuits across
switches for reverse supply protection. means for reverse
conduction control.

Is This Answer Correct ?

17 Yes

1 No

Question { ABC, 6538 }

From, which load current range ( upper - lower limit
current)can Air circuit breaker used for in electrical
circuit.

Answer

we can use the air circuit breakers for 2amps upto 2,000
amps.as per the british standard.

Is This Answer Correct ?

0 Yes

1 No

Question { JSW, 27467 }

why transformer is giving some humming noise .....?

Answer

due to the eddy current losses. Because whenever we provide
the power supply to the transformer emmidiatly flux run in
the core.hence due to the silicone immitted core the
insulation between one layer to another layer is becomes
lettle and the fulx will go high which is becomes vibration
and giving the noise. Which we can observed nearby the
transformer.

Is This Answer Correct ?

7 Yes

23 No