Electrical Engineering Interview Questions

What is master trip relay? How does it work?

4139

What is the difference between PLC & DCS?

1160

What is the instrument to check the rotating diode fuse of alternator in running conditions?

1100

why in dc generator field rheostate kept in maximum position?

2691

What is Harmonics how it is produced and what is the method to control the same

1112

Why dc voltage used to excite alternator field in stead of ac?

4548

why voltage rating of transformers are in multiples of 1.1?

3335

what should be distance between phase to phase in 415v system?

NTPC,

4165

can we correct the p.f.of ac generator?

3536

What is the effect of impedance on the heat losses in case of AC system??? Does heat losses really depends on the impedance or depends only on resistive component only..??

3113

In a poly phase circuit if clamp on meter shows same load on three phases and their sum on neutral then why we use three and a half core cable or maximum the same size of core as that of phase?

1904

how to determine kilowatts (real power) is used in energy meter? is it apparent power effect the disk rotation?

1922

When will you multiply and devide with derating factors to the actual value while sizing the cable?

809

why we are used armed coble for wiring of 3phase motor?

3013

how to improve my communication skills

5429

Un-Answered Questions { Electrical Engineering }

how to calculate cable size in diffrent loads?

973

What should be the voltage between Neutral and Ground in secondary side of the step down transformer (230 V to 110 V) with no load condition?

955

what is the size of ht cable of 33kv ht line and transformers ratings are 1 Mva and 5mva.please send formula also.

268

what is is the potential diffrence between two phase ?

3705

what is the difference between switchgear and circuit breakers and is there any difference between outdoor and indoor switchgear and circuit breakers , and how would you differentiate between switch yard and substation and grid station . thanks

857

what happen if the supply is given to the stator of the 3phase induction motor with out assembling the rotor ?

834

if the armature current in a dc generator is ac ( sinusoidal ) why doesnt the sjhape af armature mmf a sinusoidal (ni) ? armature mmf in case of a dc machine is triangular.

853

Briefly define and explain the following different types of Pulse Amplitude Modulation (PAM) with some examples. i) 2-PAM ii) 4-PAM iii) 8-PAM iv) 16-PAM v) Quadrature Amplitude Modulation (QAM)

961

how to calculate the surge level of surge suppressors related to the SF6 cicuit breakers?

863

why we use two slope(differential & restraining) in differential relay.but in busbar protection differential we are using only one slope?please explain

1007

Is there any problem about which the drive (inverter) doesn't show/display the alarm and/or fault but instead of this , it doesn't work ? I want to know that could there be any kind of problem in the drive when the drive doesn't display the alarm and/or fault ?

848

Explain the following and how these are working with PLC Unit 1 I/O Module Card 2 Adaptor Card 3 Ribbon Adaptor 4 I/O bus 5 I/O Devices

530

I have a small system with two motors that are running on 380 vac, 60 hz. These motors are expensive and I usally get them from Brazil. I am adding another motor to the system, but I want to purchase a 480 vac, 60 hz motor to use. It will be on a VFD that is rated fro 380 thru 480. Is this posible and will I have to use a larger motor and derate it?

840

How to calculate no of Lighning arrestors are required for protecting 50mX 50m*20m cubical building and locations of LA?

837

what is the physical connection of a analog i/p to a analog i/p module (ab plc)and through a analog o/p module(ab plc) to a analog o/p . and how all the process control by scada

845