Interview Questions Answers in Electrical Engineering

Questions / { thowsif }

Questions Answers Category Views Company eMail

Why use only DC supply to charge batteries why not AC Supply??

APC, Emerson,

3 Electrical Engineering 6542

Answers / { thowsif }

Question { TCS, 19710 }

Explain types soft starters?

Answer

Delta Primary & Star Secondary &

Delta Primary & Delta Secondary

This two arrangemetns are imposible....

Is This Answer Correct ?

2 Yes

7 No

Question { 6100 }

How silicon gel sucks moisture in the transformer, its have
any small exaust fan behind silicon gel.

Answer

Silicon gel is an good absorber of Moisture,their is no fan
in breather of the tansformer.

Is This Answer Correct ?

6 Yes

0 No

Question { HAL, 22911 }

How many no of flip-flops are required to get 16 bit counter

Answer

One Filp Flops can used for Count of 4 Bits,

So For 16 Bits,total no of F/F Required is 16/4=4 No's.

Is This Answer Correct ?

4 Yes

2 No

Question { Bhel, 32100 }

HOW TO FIND OUT 1. LINE CURRENT, 2. PHASE CURRENT IN AN
ALTERNATOR / TRANSFORMER WHICH IS FEEDING A I)STAR LOAD ii)
DELTA LOAD, USING A CLAMP METER.

NORMALLY WHEN WE USE CLAMP METER IN A DG SET THEN WHAT DO
WE GET?? PHASE CURRENT OR LINE CURRENT.

Answer

In Star System Line Current = Phase Current

In Delta System Line Current = Root 3 Times the Phase
Current.

It Only a Line Current not the Phase Current.

Is This Answer Correct ?

13 Yes

2 No

Question { apspdcl, 42136 }

What is effect of power factor on change in voltage

Answer

In a AC Ckts, P=V*I*Pf(Single Phase)

i.e, Voltage= P/I*Pf

As the Pf incereases the Voltage will Decrease.

Is This Answer Correct ?

42 Yes

16 No

Question { 20397 }

what is the diffrence between kav and kvar?

Answer

KVAR=KW*Power Factor

KVAR-Reactive Power

KW-Active Power.

Is This Answer Correct ?

7 Yes

9 No

Question { Badve, 95916 }

what should be distance between two electrical earthing pit
as per i.e.e

Answer

As per IEE Rule it should be minimum 5 Meters...

Is This Answer Correct ?

13 Yes

20 No

Question { 9533 }

which transmission is cheaper ac or dc?

Answer

DC Transmision is Cheaper & most efficient than AC.

Is This Answer Correct ?

5 Yes

3 No

Question { Essar, 7925 }

in 3-phase transformer which type of transformet is used in
output side?

Answer

Step Down Transforme...It is Delta-Star..

Is This Answer Correct ?

5 Yes

3 No

Question { BARC, 35071 }

Why transformer is not rotating?

Answer

Transformer is a static device which transfers voltage from
one circuit to another circuit without changing the
frequency(changes the voltage level).

Thier is no generation or Converation of Energy,So thier is
no need to cut the magnetic field as in case of Motor or
Generator to prdouce the Energy...

Is This Answer Correct ?

3 Yes

15 No

Question { 8800 }

Can without battery on line UPS,off line UPS or Invertor
works please brief.

Answer

For the Operation UPS Battery is Essential,

UPS Will work without a Battery also,but in event of Power
Faulure it will not supply the power to the load as thier
is No Backup Power..

Is This Answer Correct ?

10 Yes

2 No

Question { 16599 }

why we are using star connection and delta connection?
difference?

Answer

In Star is used for 3 Phase 4 Wire System &

Delta is used for 3 Phase 3 Wire System.

Difference:-
In Star Line Voltage is Root 3 times the Phase Voltage.
In the Simple term in Delta only R,Y&B Wires..

In Delta Line Voltage is Equal to the Phase Voltage.
In the Simple term in Delta its R,Y,b & N, 4 Wire System..

Is This Answer Correct ?

28 Yes

42 No

Question { Emerson, 4532 }

What is High Frequency Grounding????

Answer

High Frequency Grounds to reduce or eliminate high
frequency transients by achieving
a common ground reference for all equipment within a
contiguous area.

Is This Answer Correct ?

0 Yes

0 No

Question { Emerson, 7310 }

What is TVSS Protection???

Answer

Transient Voltage Surge Suppressors(TVSS)
for equipment, panel and motor protection,UPS's
applications are specifically
designed to provide long life, even
under the most adverse over-voltage
conditions.

The purpose of a TVSS is to eliminate or reduce damage to
data processing equipment
and other critical equipment by limiting transient (surge)
voltages and currents (surges) on
electrical circuits. These transients or surges may come
from inside a facility, or may be
injected into a facility from the outside.

Is This Answer Correct ?

15 Yes

0 No

Question { 6344 }

what is the charging battery current of 80 kva UPS/100AH
bocket make battery.

Answer

For 100AH Rocket ES-12-100 Battery the Maximum Charging
Current is 25A..

Pls find the following link FYI,

http://www.way-india.com/rocket_battery_specs.html

How many number of Batteries do u hv for ur 80KVA UPS?????

Is This Answer Correct ?

0 Yes

1 No