Electrical Engineering Interview Questions

While connecting bulb in Series/Parallel,there is any difference in glowing

4586

When we use air circuit breaker, it has O/L protection ,time delay SC protection, Instataneous SC protection & ground fault protection. They all have some setting range. But what is the suitable/allowable setting for the above protection which will be safe for the equipment? For example-O/L protection setting have a range of (0.4,0.45,0.5,0.55,0.6,0.65,0.7,0.8,0.9,1.0)xIn Time delay SC protection have a range of (1.25,1.5,2,3,4,6,8,10,12)xIn Time delay setting is 0.02,0.1,0.2,0.3,0.4 Instataneous setting is fixed to 20xIn Gound fault setting is given 100A,300A,600A,900A,1200A This setting are for 2500A ACB. So what will be the basic allowable setting for the above protection? is there any formulae to calculate this<

1596

Why the meters sonnected to metering core of CT are not damagedon event of a fault??? Explain the phenomena??

4003

Does the isolator has a making capacity????????

4298

How to determine earth fault level to set relay for a normal distribution system of 11 kV , 100 A load????????

TCS,

3412

why is the number of turns different in current and potential coils of wattmeter..?

2688

Why the Transformer connection is changing in different transformer?(Like Star & Delta,Delta & Delta,Star & Star,Delta Star) From that connection where it is used?

5970

1)What will happen when 240 VDC supply is connected to 240VAC supply(DC supply +ve is connected to phase of AC supply & DC supply is to neutral of AC supply). 2)Also what will happen when 240 VDC supply is connected to 240 VAC supply in reverse polarity as of Sr. No 1.

3876

What will happen when more than one star neutral points at same voltage level are connected to earth by metallic conductor?

TCS,

3257

What is the unit of inertia constant of rotating machines? Which has more inertia constant between turboalternator and hydroaltermanor and why?

15423

Why CT secondary should not left open??????????

5877

for a 11kv transmission line what capacity of CTs & PTs are required?

9247

what is method for testing CT

DCM,

1535

Can the efficiency of transformer be measured with the help of wattmeter readings taken at primary and secondary side? Support the answer.

3623

Classical power system stability was mainly focussed on rotor angle stability but modern power system stability has more focus on voltage stability.Why?

6081

Un-Answered Questions { Electrical Engineering }

Define bibo stability.

582

Draw a SLD of DG distribution up to main LT panel?

8760

Which capacitor is preferred for high voltage and frequency?

520

How to protect a Dosing pumps/any sensitive equipment (single phase) from surge protection inside a food factory.

1215

Operation of isolators.

1374

I am going to appear for the RRB Chennai junior Engineer online exam. Please send me the previous exams question papers (also solved) to my mail id: rrkhandhar@yahoo.com

1450

What is the height of DA, DAL, DB, DC & DDE tower?

1626

how to calculate earth fault relay current and CBCT ratio

7639

HOW TO DESIGN THE body EARTH cable(Copper Conductor) size for 60KVA UPS?

1483

is there any device that works properly accept relay, it may be fuse but if i want fuse of 33kv 300 amp it is avaliable, pls give me details

1498

Application Comparison between 22KV (UE)and 33KV (E) system. Are we allowed to use 33KV (E) cable in lieu of 22KV (UE) cable. What are the technical disadvantages.

1748

CALCULATE THE TOTAL VOLTAGE DROP AND SELECT THE CABLE SIZE IN MM-SQARE FOR A PANEL-262KW AT 110 METER FROM THE SOURCE SUPPLY , SUPPLY VOLTAGE 240/415

2160

Which motor will you choose which can operate in both lagging as well as leading power factors?

571

Application Comparison between 22KV (UE)and 33KV (E) system. Are we allowed to use 33KV (E) cable in lieu of 22KV (UE) cable. What are the technical disadvantages.

2200

what is differant beetween overload current and phase current?

1713