Electrical Engineering Interview Questions

how much cable size required for 70 kilowatt load.

299

how to find out cable size if load is 2800 watts, 230 volts AC supply and load distance is 1800 meters

295

How to find out damper winding failure for synchronous machine?

244

How to calculate MCB Breaking capacity.

173

What is making & breaking current ???

JLL,

283

Where can i get practical knowledge of solar system?

272

What is contract demand in solar system?

336

Explain the operation of grid connected central solar inverter ?

350

My load is 1635 KW. & current pf is 0.884, I have to improve it for 0.99.Please suggest what KVAR value is needed?

286

how to select correct size of power cable for inverter duty motor

155

What's voltage?

431

What value of resistance required between Saftey earth and instrunment earth , maximum and minimum values required

521

What is the safety of UPS?

465

What does the letter CTNM in negative phase sequence relay means?

351

1 HT service how many LT Service

605

Un-Answered Questions { Electrical Engineering }

I have an existing old MCCB. ABB Model SACE, the rating are: Ue = 660 volts, Iu =1250 Amps, 3 poles, Ith (max) =800 amps at 45 deg C. I need a circuit breaker for my 3 phase motors, 380 volts 60 hz. the supplier required the minimum ampacity of the breaker to be 911 amps. can i use this breaker with rating of Iu =1250 amps but Ith = 800amps maximum?

1040

Why sometime AVR and sometime Booster coil is used in Alternator? what is the diferance between AVR & Booster coil due to which they are selected

1837

We have 750KVA DG set, we want to introduce REF relay with 1250/1A,CL PS,Current transformers.The lead distance of 2.5mm copper flexible cable from CT to relay is around 5mtrs.We would like to know the knee point votage(VK) & IM calculion for CT's

770

What is the name of the winding from which the supply is taken for load connections?

3

dg started in plc mode and load taken later one battery terminal connection will be disconnected by loose connection what will happen for dg and shall we connect battery terminals while dg in load time?

860

what is meant by 3rd hormonics ?

807

What is the difference between 2 wires RTD's and 3 wires RTD's.Kindly explain the wiring diagram.

1004

In Indian Household, generally we receive 220V AC single phase supply. But AC has 2 phases, +ve & -ve. So in +ve half cycle current is flowing...so what happens in the -ve half cycle?? Please illustrate.

988

Why derating factor os applied on Cables?

873

What is the effect on Power factor and capacitor when your company load is more than 70 % of welding transformer

632

What is Bolted fault?

951

why lightning arrestor are made in two stack of insulator but why not cvt

863

what is under coal gassification?

1023

Explain the experiment on ward leonard method of a speed control on a dc shunt motor with an suitable circuit diagram.

1452

why Lightning arrestor are made by 2 seperate stack of inslutor but why cvt are in single stack of insulator.

924