Electrical Engineering Interview Q&A :

 

 

 

 

 

Congratulations on landing that interview! Now that you have landed a plum job, you still need to make a success out of the interview  in order to get your dream job. For engineers in general an interview consists of a non technical round followed by a technical round. As you well know, engineers are supposed to have a good knowledge on the core of their discipline – because most engineering jobs are core jobs where you can end up performing poorly if your fundamentals are shaky. As an electrical engineer you are expected to be cognizant with your fundamentals like  Power Electronics Devices and Power Systems.

What is a Control System?

Ans : If a system is designed in such a manner that output quantity or variable is controlled by input quantity then such a system is defined as Control System.

 

What are the Different Types of Control Systems ?

 

Ans : There are primarily two types of  Control Systems – Open Loop Control System and Closed loop Control System. Open Loop Control Systems are systems in which Output Quantity has no effect ( feedback)  on  the performance of Input Quantity. Closed Loop System is one in which Output Quantity influences the performance of Input Quantity.

Define electron in outer orbit?

Ans : It is known as valence.

What are the various kinds of cables used for transmission of electricity?

Ans : Mainly 3 types of cables are used based on thermal capacity – Low tension cables, transmits voltage upto 1000 volts, High Tension cables that transmits voltage upto 23000 volts and Super Tension cables transmits from 66kv-132kv voltage.

What does the different colours on wires indicate?

Ans : Black wire is used commonly for power supply in all circuits. This is also known as hot or live wire. Red wire is a secondary live wire used in 220 volt circuit and used to interconnect. Blue and Yellow wire : These wires are used to carry power but not for wiring outlets of  common plug in electrical devices but for live wire pull through conduct in devices like fans, switched outlets etc. White and Gray wires are used as neutral wires that carry unbalanced load to the ground.Green wires, connected to grounding terminal in an outlet box to the ground bus bar within an electric panel.

How do you decide the size of electrical wire?

Ans : Wires are sized by the American Wire Gauge System which measures the wire capacity. Generally smaller the wire, higher the capacity.

Difference between a Generator and Alternator?

Ans ; The generator has a stationary magnetic field with a rotating conductor whereas alternator has a stationary conductor and a rotating magnetic field.

Why are AC Systems preferred over DC Systems?

Ans ; AC system are preferred to DC systems due to the following reasons –  firstly, AC voltage  is easier to maintain for transmission and distribution. Secondly, pnat costs for AC transmission are much lower. Thirdly whenever a fault occurs in an system the AC system can be quickly switched off as the sine wave current will naturally tend to zero at some point making the current easier to interrupt.

 

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